Double Stars - Orbits

A detailed description of the project, the data sources, additional websites and how you can contribute visual observations and photographs of double stars to the project are summarized in our introduction.

Double Star Lists:

Complete List (Index)

Sketches (Index)
Photographs (Index)

Orbits (Index)

Double/Multiple Stars	483
Visual Observations	1228
Sketches	205
Photographs	24
Observers	15
	Werner E. Celnik, Berthold Fuchs, Sarah Gebauer, Christopher Hay, Gerd Kohler, Karsten Kopp, Winfried Kräling, Jens Leich, Stefan Loibl, Mark McCarthy, René Merting, Uwe Pilz, Jörg S. Schlimmer, Frederik Wanink, Robert Zebahl

m₁

m₂

Year

Coordinates (J2000.0)

HO208

8^m.2

9^m.8

1.1"

186°

2016

Peg

00^h01^m29.19^s / +30°44'08.70"

Mark McCarthy

Fremont (California/USA)

508mm (333x)

Light orange stars, split with 333x. WDS calls it physical and even provides an orbit with a 649-year period, but they do not share parallax ranges (-54%), in spite of a very close 154 AU weighted separation, 1.63/1.15 Msol, the radial velocity delta (15.51) greatly exceeds the escape velocity (6.18) -- so these are not gravitational

BU733, 85 Peg

5^m.8

8^m.9

0.4"

12°

2015

Peg

00^h02^m10.18^s / +27°04'55.60"

Mark McCarthy

Fremont (California/USA)

508mm (667x)

85 Peg. With apodising mask. Difficult, see a brightening with averted vision and foveal coaxing, but does show as faint star briefly. My PA is ENE, which is slightly incorrect. 26.28 year period, this one is widening for apastron in 2035

STF3056

7^m.7

8^m.1

0.7"

143°

2018

And

00^h04^m40.09^s / +34°15'54.70"

AB-C

7^m.1

10^m.1

26.3"

4°

2017

AB-D

7^m.1

10^m.6

95.2"

238°

2020

10^m.1

10^m.6

113.1"

227°

2015

René Merting Drachhausen (Germany)	76mm (29x)	AB-C: bei 29x ist nördlich von AB eine ganz schwache Komponente erkennbar, gut getrennt - AB wirkt leicht gelblich, C eher kupfer-grau
Sarah Gebauer Germany	100mm (73x)	die Komponenten AB erscheinen als ein Stern, C liegt nördlich davon und ist wesentlich schwächer und Komponente D, die ähnlich hell wie C erscheint, liegt westlich von AB gesehen
René Merting Drachhausen (Germany)	320mm (45x)	AB-C: bei 45x ist Komponente C im Norden gut abgesetzt von AB zu erkennen - Helligkeitsunterschied 2-3 Größenklassen - AB ist weiß-gelblich, C wirkt kupfer-grau

STT547

9^m.0

9^m.2

5.9"

191°

2021

And

00^h05^m41.03^s / +45°48'43.30"

René Merting Drachhausen (Germany)	100mm (32x)	bei 64x klare Trennung - ein relativ schwaches Pärchen - zurück auf 32x stehen beide dichter zusammen und können knapp getrennt werden
Uwe Pilz Leipzig (Germany)	105mm (144x)	Der nahe gelegene ß997 konnte nicht getrennt werden

STF3060

9^m.3

9^m.7

3.4"

136°

2020

Peg

00^h05^m55.56^s / +18°04'34.40"

Mark McCarthy Fremont (California/USA)	317mm (553x)	Very close, ~3", equal brightness, pretty faint.
Mark McCarthy Fremont (California/USA)	508mm (205x)	Light orange stars, near equal, well split. [Spectral class F8 (yellow-white)]. WDS physical with a 3804-year period. There is 79% overlap of their parallax ranges, a very close 129 AU weighted separation, 0.75/0.71 Msol, and the radial velocity delta (0.69) is far less than the escape velocity (4.48). so these are gravitational

STF3062, V640 Cas

6^m.4

7^m.3

1.5"

6°

2020

Cas

00^h06^m15.81^s / +58°26'12.50"

Robert Zebahl Leipzig (Germany)	152mm (129x)	Nice view, clearly split, but tight with visible difference in brightness.
Mark McCarthy Fremont (California/USA)	152mm (175x)	: A nice double-double with STF 3057, near equal and closely split
Frederik Wanink Itterbeck (Germany)	254mm (460x)	leicht
Mark McCarthy Fremont (California/USA)	317mm (277x)	Light yellow and a more orange yellow B, 3-4", 1 delta mag. PC (70.07 L.Y.)
René Merting Drachhausen (Germany)	320mm (320x)	erst bei 320x ist Komponente B knapp getrennt nördlich von A zu erkennen - beide Sterne sind relativ hell und haben relativ große Beugungsscheibchen, so dass die Trennung nur knapp zu sehen ist - nicht wirklich schön, wenn man in den Nächten vorher mit einem Refraktor Doppelsterne beobachtet hat

★

STF2

6^m.7

6^m.9

0.9"

15°

2019

Cep

00^h09^m20.18^s / +79°42'52.40"

Uwe Pilz Leipzig (Germany)	105mm (198x)	Schneemann-Figur. Abstand 0“91
Mark McCarthy Fremont (California/USA)	152mm (175x)	Light orange stars, very tight, hairline split, near equal mag. Physical with a 540-year period it is to slowly widen. 22% parallax overlap, only 82 AU weighted separation, 2.16/2.10 solar mass
Frederik Wanink Itterbeck (Germany)	254mm (640x)	getrennt

BU1026

7^m.2

8^m.5

0.4"

325°

2018

Cas

00^h12^m08.05^s / +53°37'26.10"

Mark McCarthy

Fremont (California/USA)

508mm (533x)

Split with seeing, 2 delta mag, fairly difficult, PA WNW. Currently 0.345" it will tighten and have a northerly PA by 2040

★

STF13

7^m.0

7^m.1

1.0"

49°

2018

Cep

00^h16^m14.02^s / +76°57'03.00"

Mark McCarthy

Fremont (California/USA)

152mm (175x)

Equal white stars, hairline split. Nice! Physical with a 1245-year period. 69% parallax range overlap, 173 AU weighted separation, 2.63/2.47 Msol

★

AC1

7^m.3

8^m.3

1.9"

291°

2020

And

00^h20^m54.10^s / +32°58'40.90"

Robert Zebahl Leipzig (Germany)	102mm (125x)	Very attractive, relatively close with a clearly visible difference in brightness. In the immediate vicinity a brighter star shines in a lovely orange. Very nice contrast!
Uwe Pilz Leipzig (Germany)	105mm (200x)	orange. Leuchtend gelber Stern in 5' Abstand
Mark McCarthy Fremont (California/USA)	152mm (175x)	Around half a delta mag, nice and close split. Physical with a 525-year period. At apastron

★

BU394

8^m.5

8^m.8

0.8"

279°

2018

Cas

00^h30^m45.56^s / +47°31'47.50"

Mark McCarthy

Fremont (California/USA)

317mm (553x)

Very fine, pop split with seeing, near equal.

STT12, lam Cas

5^m.3

5^m.6

0.1"

220°

2019

Cas

00^h31^m46.32^s / +54°31'20.30"

Mark McCarthy Fremont (California/USA)	317mm (553x)	Lambda Cas: Maybe out of round? Marginal
Mark McCarthy Fremont (California/USA)	508mm (667x)	Lam Cas. Very bright, through the speckle pattern I can see elongation with subtle notch with B maybe to the west? [Correct!] Two other stars in field. Short period, 245 year period but it's whipping around A at the moment, 0.112" now, will make a quarter turn by 2037 but still be nearly the same impossible separation.

VYS2, V547 Cas

10^m.6

12^m.2

3.5"

186°

2020

Cas

00^h32^m29.43^s / +67°14'08.80"

Mark McCarthy

Fremont (California/USA)

508mm (333x)

V547 Cas. Faint, very fine pair, seen at 205x and had a better look at 333x. Wide, ~4" slightly reddish faint stars. SkyTools brought this up as a short period pair, however it won't make a significant change in my time. It turns out A is also a pair, MCY 1 Aa-Ab, 10.8/12.5 0.5" with a period of only 15.59 years -- discovered by one D.W. McCarthy (no relation!) in 1989 during the first results of the Steward Observatory Infrared Speckle Camera using their 2.3 meter telescope. The Ab star has a mass of only 0.18 of the sun. I think it is gettable visually with the Challenger on a good transparent night, or with the Lick Great Refractor if I ever have the good fortune to observe with it

★★

eta Cas, 24 Cas

STF60

3^m.5

7^m.4

13.6"

326°

2020

Cas

00^h49^m06.29^s / +57°48'54.70"

STF60

3^m.5

11^m.4

225.0"

260°

2000

STF60

3^m.5

12^m.8

189.4"

354°

2011

STF60

3^m.5

10^m.2

75.6"

126°

2015

STF60

3^m.5

11^m.5

378.3"

276°

2000

STF60

3^m.5

9^m.5

419.7"

259°

2012

STF60

3^m.5

8^m.4

701.1"

355°

2012

SMR2

3^m.5

11^m.6

90.3"

73°

2012

SMR2

3^m.5

12^m.3

237.1"

262°

2012

Robert Zebahl Leipzig (Germany)	70mm (57x)	AB: Easy to split with big difference in brightness. Fainter component appeared deep orange to slightly red colored, brighter component tends to be more slightly yellowish.
René Merting Drachhausen (Germany)	100mm (32x)	AB: bei 32x ist Komponente A so hell, dass B trotz des augenscheinlich großen Abstandes von 13,4" nur knapp getrennt zu sehen ist - Komponente A ist gleißend hell-gelb, B dürfte mindestens 3 Größenklassen schwächer sein und wirkt dadurch dumpfer
Uwe Pilz Leipzig (Germany)	105mm (53x)	AB: leicht
Uwe Pilz Leipzig (Germany)	105mm (288x)	kein Sternentstehungsgebiet!
Sarah Gebauer Germany	150mm (54x)	AB: bei 54x erst nur einen Stern gesehen, doch da, ganz schwach darunter doch die wesentlich schwächere, zweite Komponente entdeckt
Robert Zebahl Leipzig (Germany)	152mm (30x)	AB: 2021-09-11: Light yellow & red-brownish.
Winfried Kräling Marburg (Germany)	152mm (175x)
Mark McCarthy Fremont (California/USA)	317mm (553x)	AB: Nice yellow pair. A is a red tainted yellow, B is cleaner.
René Merting Drachhausen (Germany)	320mm (72x)	AB: bei 72x ein echt fetter Farbkontrast, Komponente A ist gleißend hell und zitronengelb, B zeigt sich knallig orange - beide Sterne sind gut getrennt voneinander zu beobachten - sehenswert

★

BU232

8^m.5

8^m.8

0.9"

256°

2018

Cas

00^h50^m25.10^s / +50°37'49.60"

AB-C

8^m.5

10^m.1

24.5"

300°

2018

Mark McCarthy Fremont (California/USA)	203mm (533x)	AB: Nice, well split, near equal. Part of a triple, the next one much wider in same PA and two delta mag. [AB-C is 10.06 24.5"]
Mark McCarthy Fremont (California/USA)	317mm (553x)	AB: Neat near equal orange and yellow. Split with seeing, 1".
Mark McCarthy Fremont (California/USA)	317mm (553x)	AB-C: C 2 delta mag fainter than B, about 25" separated, is the +1 star with BU232AB

BU1099

6^m.1

6^m.6

0.2"

9°

2010

Cas

00^h56^m46.94^s / +60°21'46.30"

Mark McCarthy

Fremont (California/USA)

508mm (889x)

Obvious elongation but no notching, PA seems NNE, in a lot of diffraction. 83.1-year period, currently 0.157", it will make more than a quarter turn and widen to 0.2" by 2038. Burnham discovered in 1889 with the Lick 36-inch at 0.2" and says it's a "close and difficult" pair

HLD4

9^m.0

9^m.5

0.4"

50°

2016

Cas

00^h57^m35.79^s / +54°23'44.80"

Mark McCarthy

Fremont (California/USA)

508mm (533x)

Yellowish stars, nicely split, a near equal. [this pair is widening, will get a little easier, was 1" at discovery in 1881 -- Holden, Lick director.]

STF79, 164 And

6^m.0

6^m.8

7.9"

195°

2018

And

01^h00^m03.56^s / +44°42'47.70"

Robert Zebahl Leipzig (Germany)	55mm (25x)	Beautiful double star, relatively tight with visible difference in brightness.
René Merting Drachhausen (Germany)	320mm (45x)	ein wunderschöner Doppelstern für 45x - im Umfeld fallen zwei relativ helle Sterne sehr dicht stehend auf - B ist eine halbe Magnitude schwächer und strahlt zwar auch weiß wie A, aber etwas schmutziger
Mark McCarthy Fremont (California/USA)	508mm (205x)	164 And. Dual white headlights, slight mag difference. Physical

★

MAD1

7^m.7

9^m.1

0.9"

0°

2020

And

01^h00^m35.58^s / +47°19'14.60"

Mark McCarthy

Fremont (California/USA)

508mm (533x)

Exceptionally fine split with 333x, obvious with 533x, getting really nice airy disks. ~2 delta mag, <1", pale yellow A and very light green B. Physical pair with a 925 year period.

★

A2901

7^m.1

7^m.8

0.4"

64°

2018

Cas

01^h01^m30.15^s / +69°21'30.70"

Mark McCarthy Fremont (California/USA)	152mm (285x)	Seems a very subtle out of round, but not certain. Physical with a 1517-year orbit, will not significantly widen in my lifetime. Discovered at 0.2", 0.4" now. No Gaia data
Mark McCarthy Fremont (California/USA)	317mm (885x)	Elongated to notched with seeing

STT21

6^m.8

8^m.1

1.3"

176°

2020

And

01^h03^m01.54^s / +47°22'34.10"

Robert Zebahl Leipzig (Germany)	102mm (160x)	2020-11-02: The double star appears clearly elongated, but with no visible notch.
Uwe Pilz Leipzig (Germany)	120mm (180x)	weiß
Mark McCarthy Fremont (California/USA)	508mm (333x)	Nice pale yellow bright stars, ~2 delta mag, needed 333x clearly resolve, ~1". Physical pair with 450 year period

STT515, phi And, 42 And

4^m.6

5^m.6

0.5"

114°

2021

And

01^h09^m30.12^s / +47°14'30.60"

Robert Zebahl Leipzig (Germany)	102mm (280x)	2020-11-04: Seeing 3-4/5; In no way separable or detectable as a double star.
Uwe Pilz Leipzig (Germany)	120mm (180x)
Robert Zebahl Leipzig (Germany)	152mm (300x)	2020-11-06: Seeing 3/5; Not detectable as a double star.
Mark McCarthy Fremont (California/USA)	508mm (677x)	Phi And. I get elongation in the speckle matter, but no better resolution. Bright 0.52" pair

★

BU235

Aa-Ab

7^m.5

7^m.8

0.8"

143°

2018

Cas

01^h10^m34.31^s / +51°00'47.80"

Frederik Wanink Itterbeck (Germany)	254mm (640x)	Mehrfachsystem
Mark McCarthy Fremont (California/USA)	508mm (333x)	Amazing system with five faint pairings, but the main attraction is Aa-Ab, near equal bright A, hairline at 205x and and a nice clean split at 333x, light yellow stars, slight magnitude difference. Seeing giving me nice round disks. Terrific. Physical pair with a 278 year period. Amazingly, Burnham discovered this with his 6-inch

STT28 & STTA14 & BU1359

STT28

7^m.5

8^m.8

0.9"

296°

2006

Cep

01^h19^m07.19^s / +80°51'42.60"

STTA14

AB-C

7^m.6

6^m.7

127.6"

24°

2003

BU1359

6^m.7

11^m.6

70.2"

154°

2015

Christopher Hay Seeheim (Germany)	7x45	STTA14 (AB-C): Handheld. AB-C well separated.
Christopher Hay Seeheim (Germany)	10x42	STTA14 (AB-C): AB-C: Sweeping the field on the lookout for S405, STTA14 ist immediately striking as double, AB wide apart from C.
Christopher Hay Seeheim (Germany)	15x60	STTA14 (AB-C): AB-C: Wide pair, strong presence in 3.3° FOV. Northern component (C) clearly brighter. Attractive triangle of stars 1.5° to the south.
Christopher Hay Seeheim (Germany)	180mm (200x)	STT28 (AB): AB: Component B flashes out in good moments. PA estimated at 295° without prior knowledge. A physical double at a distance to us of 510 light years. Observed 1 March 2021, current separation 0.846" according to Stelledoppie.

BU4

7^m.1

8^m.9

0.6"

114°

2018

Psc

01^h21^m19.23^s / +11°32'12.30"

Mark McCarthy

Fremont (California/USA)

152mm (175x)

Very subtle out of roundness. There is another very faint wide B (AC, 7.12/13.60 29.3"). Discovered at 0.5" with his 6-inch, so Burnham must have had a great night. WDS says physical, but not Gaia data on the primary

★

STF115

7^m.1

7^m.3

0.5"

156°

2020

Cas

01^h23^m21.27^s / +58°08'35.60"

Mark McCarthy Fremont (California/USA)	317mm (553x)	Peanut, near equal. in nearly the same FOV with Detla Cas, V 465 pretty orange star, and NGC 457, a loose moderately rich open cluster
Mark McCarthy Fremont (California/USA)	508mm (533x)	Wonderful split, more than hairline, white stars, near equal. Nice airy disks. Physical with 222 year period, Struve discovered at 0.7" approaching apastron

V773 Cas

BU870

6^m.3

8^m.7

0.6"

332°

2010

Cas

01^h44^m17.96^s / +57°32'11.80"

GUI2

6^m.3

16^m.0

18.3"

57°

2015

ARN55

6^m.3

9^m.9

160.5"

45°

2003

Mark McCarthy Fremont (California/USA)	317mm (553x)	AD: Very wide separation 1 delta mag. physical double. This is the AD pair of a more complicated system. AB = V773 Cas = BU 870 which is 6.29/8.68 0.3", AC = GUI 2, 6.29/16.00 16.8".
Mark McCarthy Fremont (California/USA)	317mm (553x)	AD: Picking up a pinpoint in A's diffraction, very faint with seeing, <1", 3-4 delta mag, white. Marginal.
Mark McCarthy Fremont (California/USA)	508mm (1067x)	AB: Elongated at 667x, with 1067x it is a clear elongation with the B star sticking out like a stump, but not notched. It is now near periastron, and will widen rapidly to 0.448" by 2030. 184.9 year period. Need to go back and make a sketch, since it will be on the opposite side of the A star in 2030

STF158

9^m.0

9^m.4

2.2"

272°

2018

Tri

01^h46^m44.07^s / +33°09'45.50"

Mark McCarthy Fremont (California/USA)	203mm (205x)	Nice split, pretty wide considering low magnification. Orange-yellow stars about half delta mag
Karsten Kopp Köln (Germany)	600mm (180x)	Doppelstern noch gut zu trennen. Der Helligkeitsunterschied beträgt knapp eine Magnitude und der etwas hellere Stern leuchtet gelblich und der schwächere orange gelb.

HO311

8^m.2

7^m.8

0.4"

178°

2018

Ari

01^h51^m13.34^s / +24°39'08.00"

Mark McCarthy

Fremont (California/USA)

508mm (1067x)

Nice clear split with seeing, more near equal but there is a noticeable magnitude difference, white stars

BU260

8^m.8

9^m.0

1.1"

261°

2018

Ari

01^h53^m14.21^s / +15°26'00.30"

Mark McCarthy

Fremont (California/USA)

203mm (533x)

Fine pair, well split, half delta mag

BU513, 48 Cas

4^m.7

6^m.7

0.6"

320°

2013

Cas

02^h01^m57.55^s / +70°54'25.40"

Mark McCarthy Fremont (California/USA)	152mm (285x)	Overlapping disks at all powers, 1 delta mag. Burnham says: "This most interesting binary was discovered with the 18.5-inch, but at that time it was easily seen with the 6-inch. It is now (1898) a very difficult object, and only measurable with a large aperture under the best conditions." 1.0" at discovery, it is now 0.4" and found to have a 61.14-year period and will continue to tighten until the 2040s. I don't find Gaia data on the secondary
Mark McCarthy Fremont (California/USA)	317mm (553x)	Searched around the swollen, shimmering bright A star disk and felt there was a faint close B trying to resolve in the first diffraction at 553x. Apodizing mask cleaned up the image but no B resolved

alpha Psc, 113 Psc, Alrischa, Kaitain, Okda

STF202

4^m.1

5^m.2

1.9"

264°

2019

Psc

02^h02^m02.80^s / +02°45'49.40"

PWL1

4^m.1

8^m.2

404.9"

63°

2006

PWL1

4^m.1

8^m.6

434.5"

335°

2006

Winfried Kräling Marburg (Germany)	102mm (178x)	AB
Uwe Pilz Leipzig (Germany)	105mm (88x)	AB: der hellere Stern ist weiß

★

STF208, 10 Ari

5^m.8

7^m.9

1.3"

349°

2018

Ari

02^h03^m39.26^s / +25°56'07.60"

Uwe Pilz Leipzig (Germany)	105mm (200x)	helle Stelle im ersten Ring
Mark McCarthy Fremont (California/USA)	317mm (553x)	~2 delta mag, ~1" very nice. ~1 disk split. Nice!

★★★

gamma And, 57 And, Alamak

STF205

A-BC

2^m.3

5^m.0

9.5"

63°

2021

And

02^h03^m53.92^s / +42°19'47.50"

BAR22

2^m.3

15^m.0

27.9"

245°

1898

STT38

5^m.3

6^m.5

0.3"

120°

2021

Robert Zebahl Leipzig (Germany)	63mm (42x)	A-BC: Easy to split with quite large difference in brightness.
Christopher Hay Seeheim (Germany)	71mm (32x)	Fine split. A is mandarine orange. BC has trouble displaying its colour due to the overpowering light of A, but in good moments is clearly blue. A-BC is a physical double at a distance to us of 393 light years. BC is also physical, with a relatively short period of 63 years for C to circle B and a very tight periastron. Unobservable in 2013 at periastron with 0.1". Since then the angular separation has been widening rapidly and will reach 0.4" in 2029. B-C will then become observable in large amateur telescopes for three decades, after which C will fall quickly back to B.
René Merting Drachhausen (Germany)	76mm (29x)	A-BC: bei 29x äußerst knapp getrennt - Komponente A strahlt buttergelb, BC schmiegt sich im Nordosten an
Uwe Pilz Leipzig (Germany)	105mm (52x)	A-BC: einfach
Uwe Pilz Leipzig (Germany)	120mm (128x)	A-BC
Robert Zebahl Leipzig (Germany)	152mm (100x)	A-BC: Very easy. A: orange, BC: rather white.
Christopher Hay Seeheim (Germany)	180mm (110x)	A very strong pair in 0.6° FOV with powerful colour contrast, A yellow, BC ice blue.
René Merting Drachhausen (Germany)	320mm (45x)	A-BC: bei 45x ein knapp getrenntes Pärchen - Komponente A knallgelb mit einem Anhängsel nordöstlich - Komponente BC strahlt 3 Größenklassen schwächer - bei 144x wirkt BC grün-weiß, bei 45x war der Eindruck noch leicht gelblich
Mark McCarthy Fremont (California/USA)	508mm (667x)	BC: Component of STF 205, of which A is a brilliant orange and BC bright blue. In BC I can only see elongation through the speckle at 667x and 1067x. Short 62.63 year period which will get "easier" to about 0.2" by 2045
Mark McCarthy Fremont (California/USA)	508mm (1067x)	BC: I spent a good long while on this one, and tried hard to nail down the position angle. At 1067x, both with and without an apodising mask, but both times with a #80A light blue filter, which did seem to calm the diffraction a little, I had a clear view of the elongation with a strong sense of the weaker end being to the East or to the ESE. I also tried a 78% central obstruction mask, and while the diffraction became a grid, and the disks much smaller, I could clearly see the same elongation and weaker end, though at a much smaller scale. To my delight the current orbital solution puts the PA at 120.6-degrees, 0.179" separation, so I think I have detected it. I can't wait until 2033 when this becomes an easy pair!

Winfried Kräling Marburg (Germany)	127mm	A-BC: Aufnahme vom 11.09.2020 am 127/1200mm Refraktor mit Barlowlinse (~2.5x) Weit getrennt, Komponente A: goldgelb bis orange, Komponente BC: weißlich blau
Werner E. Celnik Rheinberg (Germany)	150mm	A-BC

★★★

STF227, iota Tri, 6 Tri

5^m.3

6^m.7

4.0"

68°

2019

Tri

02^h12^m22.28^s / +30°18'11.10"

Robert Zebahl Leipzig (Germany)	70mm (57x)	At 44x even separable with a clear difference in brightness, whereby the companion is almost outshone by the primary component. At 57x easy to separate. Primary component shines in bright orange, companion slightly orange. Beautiful sight together with STF232 in one field of view!
Uwe Pilz Leipzig (Germany)	105mm (88x)	weiß und blau
Christopher Hay Seeheim (Germany)	180mm (110x)	Well separated. Primary yellowish, secondary light blue. When 6 Tri drifts out of 0.6° FOV, STF232 drifts in. 6 Tri is a physical double at a distance to us of 291 light years.
Mark McCarthy Fremont (California/USA)	203mm (205x)	6 Tri. Yellow A, white b, pretty. Wide, about two delta mag
Frederik Wanink Itterbeck (Germany)	254mm (200x)	Helligkeitsunterschied deutlich
Karsten Kopp Köln (Germany)	600mm (180x)	Doppelstern ist noch gut zu trennen und der Helligkeitsunterschied ist mit gut 1,5 mag schon sehr auffällig. Der hellere Stern erstrahlt schön gelblich, der schwächer weiß. In den Momenten der wirklich ruhigen Luft, ein sehr schöner Doppelstern

★

STF234

8^m.7

9^m.4

0.6"

222°

2012

Cas

02^h17^m23.00^s / +61°21'06.50"

Mark McCarthy

Fremont (California/USA)

317mm (885x)

Light orange star, definitely elongated, maybe notched, but no convincing split. Tough little Struve.

HO216

7^m.9

9^m.4

1.4"

6°

2018

Tri

02^h27^m00.99^s / +31°17'17.30"

Robert Zebahl

Leipzig (Germany)

120mm (150x)

2021-12-10: Under these moderate conditions at 100x to 150x in no way separable.

A2329

9^m.4

9^m.6

0.6"

109°

2020

Cet

02^h27^m45.86^s / +04°25'55.90"

Mark McCarthy

Fremont (California/USA)

508mm (1067x)

Split at 533x but used barlow to confirm the PA accurately since this is a short period pair. Nicely split orange stars, half delta mag. Seeing it now at nearly the furthest extent of its orbit, it will become more difficult with time. The pair is a "mere" 55.91 lightyears away

★★

iota Cas, STF262 & CHR6

CHR6

Aa-Ab

4^m.6

8^m.5

0.6"

42°

2010

Cas

02^h29^m03.96^s / +67°24'08.70"

STF262

4^m.6

6^m.9

2.9"

230°

2017

STF262

4^m.6

9^m.1

6.7"

117°

2015

STF262

4^m.6

8^m.5

210.9"

60°

2016

Robert Zebahl Leipzig (Germany)	55mm (27x)	Only the D component was well visible. The components B & C were not visible even at magnifications up to 167x. The sky was clearly brightened (Bortle 7).
Robert Zebahl Leipzig (Germany)	70mm (120x)	Components A, B and C pretty close together, D far apart. Component B appeared slightly elongated on the first diffraction ring of the primary component. Rewarding!
René Merting Drachhausen (Germany)	100mm (142x)	AB: bei 142x zeigt sich Komponente B im SW mit gut einem Drittel das Abstandes AC, Helligkeitsunterschied 1.5 bis 2 Größenklassen AC: bei 64x getrennt, schöner Farbkontrast, Komponente A ist weiß mit einem Stich ins Gelbe, C leicht bräunlich AD: bei 32x extrem weiter Abstand zwischen A und D, Helligkeitsunterschied mehr als 2 Größenklassen (laut Stelle Doppie sogar 3.85 mag)
Uwe Pilz Leipzig (Germany)	105mm (200x)	Dreifachstern lohnend
Sarah Gebauer Germany	150mm (160x)	bei 160x sind die Komponenten AC getrennt, B leider nicht, die schwache Komponente C versinkt fast im Strahlen der hellen Komponente A, ein sehr reizvoller Anblick! Von Komponente D wusste ich während der Beobachtung noch nichts, sie taucht unter den Feldsternen der Zeichnung auch auf
Robert Zebahl Leipzig (Germany)	152mm (129x)	Component D easy to see even at lowest magnification. Component C is also easily visible at 49x. At 69x the component B is indicated, at 100x clearly visible. C appears slightly grey-bluish and obviously fainter than B. Grand sight at 129x!
Mark McCarthy Fremont (California/USA)	508mm (1067x)	CHR6 (Aa-Ab): This is a component of Iota Cas, STF 262 (which is a really pretty triple). CHR 6 at 1067x and seeing through the speckle image, I get elongation with a suspected blunter end which I assume is the B side, PA to the north [it's actually to the south -- my general orientation is correct but mis-interpret the brighter end]. Physical with 47 year period, currently at periastron and will tighten to 0.2" by 2036

STF295, 84 Cet

5^m.8

9^m.7

3.9"

302°

2016

Cet

02^h41^m14.00^s / -00°41'44.40"

Robert Zebahl Leipzig (Germany)	102mm (160x)	Quite easy at a moderate distance, whereby the companion appeared rather faint and was best visible with averted vision.
Uwe Pilz Leipzig (Germany)	105mm (144x)	trotz diesigem Himmel bei 144x indirekt erkennbar. Schwieriger bei 200x
Robert Zebahl Leipzig (Germany)	152mm (129x)	Easy. The quite dim companion is immediately visible in moderate distance clearly outside of the first diffraction ring despite few, high clouds. The primary component appeared white-yellowish.

STF296, theta Per, 13 Per

4^m.2

10^m.0

21.2"

306°

2020

Per

02^h44^m11.99^s / +49°13'42.40"

4^m.2

11^m.1

94.8"

244°

2002

10^m.0

11^m.1

88.2"

232°

2007

René Merting

Drachhausen (Germany)

76mm (57x)

AB: bei 29x ist B relativ dicht nordwestlich von A erkennbar - Trennung ordentlich - B ist sehr schwach
AC: bei 57x wird C im Südwesten von A sichtbar, noch schwächer als B und deutlich weiter entfernt

★

A2906 & STF314

A2906

7^m.3

8^m.8

0.3"

115°

2018

Per

02^h52^m52.03^s / +52°59'50.60"

STF314

AB-C

7^m.0

7^m.3

1.6"

316°

2018

Robert Zebahl Leipzig (Germany)	152mm (129x)	STF314 (AB-C): Beautifully separated, quite close together. Difference in brightness visible, but rather small. Easy to find and bright. Very nice.
Frederik Wanink Itterbeck (Germany)	254mm (460x)	STF314 (AB-C): ähnlich hell
Mark McCarthy Fremont (California/USA)	317mm (553x)	A2906 (AB): This is the brighter of the STF 314 pair. I have a feeling it is slightly elongated but nothing certain.
Mark McCarthy Fremont (California/USA)	317mm (553x)	STF314 (AB-C): near equal brightness, AB more yellow yellow-white of the two, ~2 disk separation

BU525

7^m.5

0.5"

276°

2019

Ari

02^h58^m53.11^s / +21°37'03.90"

Mark McCarthy

Fremont (California/USA)

317mm (553x)

Star is decidedly not round but does not show shape other than a stretching.

★

STF333, eps Ari

5^m.2

5^m.6

1.4"

210°

2020

Ari

02^h59^m12.73^s / +21°20'25.60"

Uwe Pilz Leipzig (Germany)	120mm (250x)
Mark McCarthy Fremont (California/USA)	203mm (205x)	Eps Ari: Beautiful split of white stars, less than 1 delta mag, a little more than 1". Very nice pair. Physical with a 1215 year period

★

STF346, 52 Ari

6^m.2

0.5"

256°

2016

Ari

03^h05^m26.69^s / +25°15'18.70"

AB-C

5^m.5

10^m.8

5.1"

358°

2005

AB-D

5^m.5

13^m.3

102.1"

83°

2013

AB-E

5^m.5

12^m.8

133.5"

192°

2014

Mark McCarthy Fremont (California/USA)	203mm (333x)	AB: What a great set! The closest are a near equal pair of white stars, elongated with a slight notch, There's a faint C ~5" and slight more than a right angle in PA. Interesting set. Physical with 227 year period
Mark McCarthy Fremont (California/USA)	317mm (553x)	AB-C: Bright yellow-white AB, orange C. ~4-5 delta mag, 5-6" PA to N. Did not notice AB 0.5"

BU1030

7^m.8

9^m.7

0.8"

102°

2016

Ari

03^h10^m06.57^s / +21°44'49.50"

Mark McCarthy

Fremont (California/USA)

203mm (333x)

Good clean split, slight magnitude difference, small pair. Really good. Physical with 571 year period

STF360

8^m.0

8^m.3

2.9"

125°

2019

Per

03^h12^m09.59^s / +37°13'03.30"

Robert Zebahl Leipzig (Germany)	70mm (67x)	Pretty faint double star. At 57x barely separable with almost touching diffraction disks. The components seemed similarly bright. At 67x still very close together, at 100x easy to separate.
Robert Zebahl Leipzig (Germany)	152mm (69x)	Split, but close together, similarly bright. The double star appears overall slightly orange compared to the surrounding stars.

★★

STT51

8^m.5

8^m.7

0.6"

353°

2019

Per

03^h12^m57.08^s / +44°17'14.70"

Mark McCarthy

Fremont (California/USA)

317mm (553x)

Very fine clean split at the finest moments, which is once every 10 seconds. 0.5", equal mag.

HU544

6^m.7

8^m.2

1.7"

103°

2018

Per

03^h15^m48.70^s / +50°57'21.20"

Robert Zebahl Leipzig (Germany)	70mm (133x)	Clearly seen as figure '8' with noticeable difference in brightness.
Uwe Pilz Leipzig (Germany)	105mm (196x)	klebt am ersten Ring
Uwe Pilz Leipzig (Germany)	105mm (260x)	im ersten Ring
Robert Zebahl Leipzig (Germany)	152mm (129x)	Wonderfully separated in equally beautiful star surroundings! Clear difference in brightness visible. To the east there is a brighter star, which shines yellowish-orange. HU544 itself seems rather cool in color.

A2345

9^m.7

10^m.6

1.1"

176°

2013

Tau

03^h27^m32.03^s / +19°11'13.40"

Mark McCarthy

Fremont (California/USA)

508mm (333x)

The faint companion is just split with seeing, around 1 delta mag, very tight <1". Physical with a 959-year period. The PA is currently precisely to the south

BU787

7^m.4

11^m.9

5.2"

293°

2016

Per

03^h34^m12.97^s / +48°37'02.90"

Mark McCarthy

Fremont (California/USA)

203mm (121x)

Very nice, white and very large delta mag B, but seen plainly with low magnification. Physical, 655.8 year period

★★★

STF412, 7 Tau

6^m.6

6^m.9

0.8"

351°

2019

Tau

03^h34^m26.62^s / +24°27'52.10"

AB-C

5^m.9

9^m.9

22.4"

53°

2014

Uwe Pilz Leipzig (Germany)	105mm (260x)	AB: A-B länglich
Christopher Hay Seeheim (Germany)	180mm (110x)	No definite elongation of AB seen at 110x, seeing is poor. But nice pinprick of light wide off to NE, seems bluish, this is the C component. AB-C is physical at 429 light years distance from us, and so is A-B, so this is a physical triple system. Very easy to find 3° due west of the Pleiades.
Mark McCarthy Fremont (California/USA)	508mm (333x)	AB: Exciting 2+1 set. AB is brilliant near equal white, nice close split <1". C is a much fainter wider star. I also cleanly split AB with the 8-inch mask, but the dark gap was narrower. Physical with a 522.16-year period

BU533

7^m.5

7^m.7

1.0"

222°

2018

Per

03^h35^m37.81^s / +31°40'48.70"

Robert Zebahl Leipzig (Germany)	152mm (225x)	At 129x clearly elongated, notched. At 225x just so separable with similarly bright components.
Mark McCarthy Fremont (California/USA)	152mm (285x)	Excellent! Near equal light yellow-orange stars, hairline at 175x and close clean split at 285x. Burnham discovered with the 18.5-inch Dearborn refractor at 0.4". WDS has medium confidence of binarity with a 463-year period, currently coming off apastron. However there is no shared parallax range (-12%), despite only 103 AU weighted separation and 1.63/1.68 Msol. This may turn out not to be binary

STF425

7^m.5

7^m.6

1.9"

59°

2018

Per

03^h40^m07.24^s / +34°06'59.30"

Robert Zebahl

Leipzig (Germany)

152mm (129x)

Beautifully separated, relatively close together, very little difference in brightness.

★★

BU536 & S437, SAO76169

BU536

8^m.1

9^m.4

1.1"

178°

2016

Tau

03^h46^m16.00^s / +24°11'23.50"

S437

AB-C

8^m.1

7^m.7

38.8"

308°

2017

BU536

7^m.7

12^m.9

18.3"

5°

2015

Christopher Hay Seeheim (Germany)	10x42	S437 AB-C: A fine, compact pair at the centre of the Pleiades. Not physical, in contrast to AB.
Christopher Hay Seeheim (Germany)	71mm (13x)	S437 AB-C: Well separated. The most double-starish pair in the whole of the Pleiades at this power.
Christopher Hay Seeheim (Germany)	76mm (20x)	S437 AB-C: Well separated. Component C is slightly orange.
Christopher Hay Seeheim (Germany)	180mm (200x)	BU 536: AB seems to plop apart in good moments, but remains uncertain. S437 AB-C: C is brown-orange, AB blue-white.
Mark McCarthy Fremont (California/USA)	203mm (333x)	BU536 (AB): Wow what a great pair. B is a clean split ~1" right next to A, approximately 1 delta. More amazing to see than I can describe. Aitken had a measure of 0.15" in 1899.70. Burnham discovered with the 18.5-inch at 0.4" and notes "It is important that the close pair should be watched and measured in the near future." Physical, 885.64 year period, now widening

STF443

8^m.2

8^m.8

6.6"

55°

2020

Per

03^h47^m02.11^s / +41°25'38.10"

8^m.2

11^m.4

106.2"

331°

2002

Robert Zebahl

Leipzig (Germany)

102mm (28x)

AB: 2020-11-08: Nicely separated, relatively close together with little difference in brightness.

STT65

5^m.7

6^m.5

0.4"

202°

2017

Tau

03^h50^m18.91^s / +25°34'46.70"

Mark McCarthy Fremont (California/USA)	178mm (333x)	Notched snowman, B is a little bluish to white A, can tell orientation, short period with PA to the SW. 61.2-year period, it will soon be at apastron. Given it's nearly edge-on orbit, I won't see significant change, except for a slightly better split, in my time
Mark McCarthy Fremont (California/USA)	203mm (533x)	For this one I used an 8-inch mask on my 20-inch telescope, since the star brightness washed out the image in full aperture. It appeared as a very tight pair, hairline split, and around 1 delta mag. I estimated the PA to the south. Approaching apastron, and won't make significant change in my lifetime in spite of the 61.2-year period

STT66

8^m.1

8^m.5

1.0"

146°

2018

Per

03^h52^m04.69^s / +40°47'50.70"

Robert Zebahl Leipzig (Germany)	102mm (187x)	2020-11-08: Already at 125x visible as figure '8'. Seeing was not good enough for higher magnifications.
Mark McCarthy Fremont (California/USA)	317mm (270x)	light orange equal magnitude, split with seeing, close ~1"

STF483

7^m.4

9^m.3

1.6"

53°

2018

Per

04^h04^m07.10^s / +39°30'35.00"

Mark McCarthy

Fremont (California/USA)

317mm (270x)

Yellow-orange star, very close, 1", 2 delta mag.

STT531, 50 Per

7^m.3

9^m.7

2.7"

353°

2018

Per

04^h07^m34.35^s / +38°04'28.30"

7^m.3

8^m.8

225.1"

217°

2015

Robert Zebahl Leipzig (Germany)	102mm (125x)	AB: 2020-11-08: Clearly separated, relatively tight, fairly large difference in brightness. Primary component appeared white-yellowish with faint companion.
Mark McCarthy Fremont (California/USA)	317mm (270x)	AB: AC is a finder split. The fainter of these has another star split 4", 2-3 delta mag., this is the AB pair.

★

omicron 2 Eri, 40 Eri, STF518

A-BC

4^m.4

9^m.3

82.7"

102°

2019

Eri

04^h15^m16.32^s / -07°39'10.30"

9^m.5

11^m.2

8.2"

330°

2019

Winfried Kräling Marburg (Germany)	102mm (178x)
Uwe Pilz Leipzig (Germany)	105mm (244x)	A ist gelblich. B fiel sofort ins Auge, auch bei 144x. C war extrem schwierig. A musste außerhalb des Gesichtsfeldes stehen, aber auch dann war er nur indirekt sichtbar. Dann aber überraschte der verhältnismäßig große Abstand B-C. ~ A ist ein Hauptreihenstern ähnlich der Sonne. B ist ein weißer Zwerg, einer der hellsten am Himmel. C ist ein Roter Zwerg, davon gibt es nicht viele in der Reichweite kleiner Instrumente. Insgesamt hat man drei Zwergsterne auf einen Blick: Einen gewöhnlichen (=Hauptreihen-) Zwerg, einen weißen und einen roten.

Berthold Fuchs

Wiesbaden (Germany)

130mm

A-BC: Triplesystem with a white Dwarf

../projects/double-stars/berthold-fuchs/photographs/Keid.png

HO328

7^m.4

9^m.1

0.4"

358°

2016

Tau

04^h17^m01.22^s / +19°40'32.60"

Mark McCarthy

Fremont (California/USA)

317mm (553x)

Very faint, very close ~0.8", emerges with seeing, hair split. Marginal

★

STF520

8^m.3

8^m.4

0.6"

83°

2019

Tau

04^h18^m14.55^s / +22°48'24.60"

Mark McCarthy

Fremont (California/USA)

317mm (553x)

Faint elongated to overlapping disks.

STT82

7^m.3

8^m.6

1.2"

324°

2020

Tau

04^h22^m44.10^s / +15°03'22.10"

Mark McCarthy

Fremont (California/USA)

317mm (553x)

Very close, 0.8" 1.5 delta mag, PA to N/NW.

STT81, 56 Per

5^m.8

9^m.2

4.2"

13°

2017

Per

04^h24^m37.46^s / +33°57'34.90"

Mark McCarthy

Fremont (California/USA)

317mm (270x)

56 Per. Pretty yellow and slight red pair, 2 delta mag.

HU1080

6^m.8

8^m.4

0.2"

266°

2016

Tau

04^h28^m59.78^s / +16°09'32.70"

Mark McCarthy

Fremont (California/USA)

508mm (533x)

Used 533x & 667x. I could detect elongation at 533x, and significant notching with 667x, enough to tell which was A & B and the position angle, which I put at nearly E-W (B is tightly WSW currently). Physical with a 40.752-year period, it is widening and reaches apastron in 2029, so maybe I'll get a clean split and a more accurate PA estimate at that time

STF554, 80 Tau

5^m.7

8^m.1

1.4"

15°

2021

Tau

04^h30^m08.60^s / +15°38'16.20"

Mark McCarthy

Fremont (California/USA)

317mm (553x)

1" 2 delta mag, PA N. Nice!

★★

STF572

7^m.4

7^m.2

4.5"

188°

2021

Tau

04^h38^m29.58^s / +26°56'25.60"

Christopher Hay Seeheim (Germany)	42mm (12x)	Slightly elongated. PA seen definitely without prior knowledge, confirmed in 3-inch.
Robert Zebahl Leipzig (Germany)	70mm (57x)	Clearly separated, easy with beautiful color contrast: A slightly orange, B white.
Christopher Hay Seeheim (Germany)	76mm (83x)	Well separated, very even matched pair.

COU2031

6^m.9

7^m.8

0.0"

28°

2011

Per

04^h46^m26.92^s / +42°20'54.20"

Mark McCarthy

Fremont (California/USA)

508mm (1067x)

A badly misshaped star, elongated, SSE PA, but nothing really clear, very small scale. Physical with a 20.58 year period, it will close to periastron rapidly in the next 5 years, and really not be detectible visually until it returns to apastron in the late 2030s

BU552

6^m.4

8^m.9

0.9"

275°

2020

Ori

04^h51^m49.92^s / +13°39'18.70"

Mark McCarthy

Fremont (California/USA)

508mm (533x)

Light yellow A and light orange B, well separated when seeing stills and the stars form airy disks, short period pair with a 97.7 year period. This will continue increasing to apastron in 2030 and beyond, though the PA will remain about the same -- I think in the future it will be splittable in lower magnifications, which is how I would notice any change. Burnham writes: "This pair was discovered with the 18.5-inch, but in looking over the old observing books used with the 6-inch, I find that on December 14, 1874, this star was noted as 'possibly a close pair'â€¦There seems to be something singular about the appearance and difficulty of this pair at times with larger apertures. It was not noted as difficult at the time of the observation in 1877. in 1890 it was a hard star with the 36-inch and on two nights in 1892, under favorable conditions, I failed to see it double at all."

STT92, 5 Aur

6^m.0

9^m.5

4.1"

285°

2017

Aur

05^h00^m18.35^s / +39°23'40.90"

Uwe Pilz Leipzig (Germany)	105mm (160x)	schwierig
Uwe Pilz Leipzig (Germany)	105mm (288x)	Nur bei sehr hoher Vergrößerung überhaupt zu trennen, schwierig

★

STF645 & BU1047

STF645

A-BC

6^m.0

9^m.1

11.3"

29°

2017

Tau

05^h09^m45.06^s / +28°01'50.20"

BU1047

9^m.1

9^m.7

0.3"

88°

2013

Uwe Pilz Leipzig (Germany)	105mm (88x)	STF645 (A-BC)
Mark McCarthy Fremont (California/USA)	317mm (270x)	STF645 (A-BC): White and grey, 2 delta mag, wide. BC is BU 1047 0.3" near equal, but not seen
Mark McCarthy Fremont (California/USA)	508mm (667x)	BU1047 (BC): Component of STF 645. Awesome flex on Struve. Near equal BC stars suspected at 533x, hairline split at 667x. A really fine little blue pair near bright white A. Physical with a 32.1-year period, it is at apastron now and will get impossibly close in the 2030s, becoming visually detectible again in the later part of that decade. Burnham discovered in 1889 with the Lick 36-inch, and recorded 0.4" separation

STF648

8^m.1

8^m.9

5.0"

64°

2020

Aur

05^h10^m59.19^s / +32°02'19.50"

Robert Zebahl Leipzig (Germany)	55mm (40x)	At 40x tight with obviously fainter component.
Robert Zebahl Leipzig (Germany)	70mm (33x)	Separated, but tight with noticeable difference in brightness.
Uwe Pilz Leipzig (Germany)	105mm (144x)	beide Komponenten gelb
Mark McCarthy Fremont (California/USA)	317mm (270x)	Light orange, half delta mag, wide.

STT517

6^m.8

7^m.0

0.7"

244°

2019

Ori

05^h13^m31.55^s / +01°58'03.70"

Uwe Pilz Leipzig (Germany)	105mm (144x)	Es erforderte einige Mühe zu sehen, welches der hellere Stern ist,
Mark McCarthy Fremont (California/USA)	203mm (333x)	Consistently split but images are bloated by poor seeing, yellowish white stars, <1", near equal

Winnecke 2, WNC2

A-BC

6^m.9

7^m.0

3.1"

159°

2020

Ori

05^h23^m51.32^s / -00°51'59.80"

Robert Zebahl Leipzig (Germany)	70mm (44x)	Double star appeared elongated.
René Merting Drachhausen (Germany)	100mm (64x)	bei 64x ein extrem eng stehendes wunderschönes Pärchen zweier gleich heller gelber Sterne - keine 8 mehr, beide sind schon getrennt - bei 107x kommt etwas mehr Luft zwischen beide, aber sie scheinen auch ein wenig Farbe zu verlieren
Robert Zebahl Leipzig (Germany)	120mm (150x)	Clearly split with nearly equally bright components.
Mark McCarthy Fremont (California/USA)	203mm (333x)	Nice near equal, light yellow-white stars, well split. nice pair [BC is A 847 7.67/7.84 0.3" and could have been gotten on a better night!]
Mark McCarthy Fremont (California/USA)	508mm (533x)	Easy and obvious pair, bright 7th mag stars ~3". [This was a first try at the short period list but I missed the object, which is A 847 BC, 7.67/7.84 0.3" -- need to try again.]

A848

6^m.9

7^m.9

0.3"

179°

2016

Ori

05^h25^m31.08^s / -00°32'38.20"

Mark McCarthy

Fremont (California/USA)

203mm (533x)

Suspect elongation at 333x, at 533x I get a snowman, very definite with seeing. White stars, noticeable mag difference

STF728, 32 Ori

4^m.4

5^m.8

1.3"

44°

2017

Ori

05^h30^m47.06^s / +05°56'53.30"

Uwe Pilz Leipzig (Germany)	105mm (288x)	sauber getrennt, Beugungsscheiben berühren sich gerade
Mark McCarthy Fremont (California/USA)	203mm (333x)	32 Ori White and off white pair, 1.5 delta mag, ~1.5". Nice and very clean with seeing

★

STF742

7^m.1

7^m.5

4.1"

275°

2019

Tau

05^h36^m26.38^s / +21°59'35.10"

Located about 0.5 degree east of Messier 1.

Christopher Hay Seeheim (Germany)	76mm (83x)	Just split. A little difficult. Suprisingly more difficult than STF572 about 15° to the northwest, although the numbers are very similar and the two systems are standing at identical elevation above horizon. At 40x STF742 is no longer definitely split, but M1 half a degree to the west is strong in 2° FOV by way of compensation.
Robert Zebahl Leipzig (Germany)	102mm (62x)	Beautifully separated, relatively tight with well visible difference in brightness. Points directly toward Messier 1 and can be observed with it in one field of view. Very nice!
Robert Zebahl Leipzig (Germany)	120mm (48x)	Nice, evident double near Messier 1. Easy to split with almost equally bright components.
Robert Zebahl Leipzig (Germany)	152mm (69x)	At 49x just so, at 69x easily separable. The fainter component appeared a little warmer in terms of color. Great view together with Messier 1 in the field of view.
Robert Zebahl Leipzig (Germany)	200mm (80x)	Nice double star with nearly equally bright components.
Mark McCarthy Fremont (California/USA)	203mm (333x)	Well separated, ~1 delta mag white stars. Physical with 2959-year period

STF749

6^m.5

1.1"

324°

2019

Tau

05^h37^m08.84^s / +26°55'28.30"

6^m.5

10^m.5

181.6"

299°

2011

Robert Zebahl Leipzig (Germany)	70mm (133x)	AB: I had the impression that in the correct position angle, without knowing that angle during observation, a minimal elongation could be detected. But observation is borderline and too doubtful.
Mark McCarthy Fremont (California/USA)	203mm (333x)	AB: Lovely near equal pair, close around 1", like distant headlights, slightly blue-green white color. Physical with 773.2358-year period
Mark McCarthy Fremont (California/USA)	317mm (277x)	AB: Hair-split, equal brightness white stars. Nice.

STF774, zeta Ori, 50 Ori, Alnitak

1^m.9

3^m.7

2.4"

167°

2017

Ori

05^h40^m45.52^s / -01°56'33.30"

1^m.9

9^m.6

58.5"

10°

2017

Robert Zebahl Leipzig (Germany)	70mm (128x)	AB: Big difference in brightness. I could see the fainter component near the first ring of the Airy pattern of the brighter component.
Winfried Kräling Marburg (Germany)	102mm (178x)	AB
Uwe Pilz Leipzig (Germany)	105mm (288x)	AB: sauber getrennt, Beugungsscheiben berühren sich gerade
Mark McCarthy Fremont (California/USA)	203mm (333x)	AB: Alnitak. Easy, 2 delta mag,~2", white
Mark McCarthy Fremont (California/USA)	317mm (207x)	AC: Alnitak:AC is a very faint star widely separated outside of the main star's glare.
Mark McCarthy Fremont (California/USA)	317mm (207x)	AB: about 2" and 1.5 delta mag.

BU1052

6^m.7

8^m.2

0.7"

183°

2020

Ori

05^h41^m40.34^s / -02°53'47.30"

Mark McCarthy

Fremont (California/USA)

508mm (533x)

Suspected at 333x, easily split with 533x & apodising mask, light orange stars approximately 1.5 delta. Short period with 105.692-year period. Burnham discovered with the 36-inch at 0.7". Currently at apastron, close to the discovery separation, it will be difficult to notice change in the next 20 years, but after 2050 it will close rapidly

BU560

7^m.8

8^m.2

1.7"

124°

2019

Aur

05^h47^m24.87^s / +29°39'26.90"

Robert Zebahl Leipzig (Germany)	70mm (100x)	Clearly visible as a double star with overlapping diffraction disks (figure '8') and small difference in brightness.
Robert Zebahl Leipzig (Germany)	152mm (129x)	Separated with very little difference in brightness, relatively tight. Overall easy.

STT119

8^m.1

8^m.9

0.7"

354°

2019

Ori

05^h47^m54.88^s / +07°57'37.50"

Mark McCarthy

Fremont (California/USA)

508mm (333x)

Suspect elongations with 8" 533x & 20" 533x, but image not good enough. But I got a nice clean split with apodizing mask, nearly perfrect disks. Orange stars well split, <1", about 1 delta mag

STF795, 52 Ori

6^m.0

1.0"

221°

2019

Ori

05^h48^m00.21^s / +06°27'14.50"

Sarah Gebauer Germany	150mm (125x)	bei 125x und 250x nicht getrennt im April 2020
Mark McCarthy Fremont (California/USA)	317mm (553x)	Bright white, near equal magnitude, near touching disks hairline split
Mark McCarthy Fremont (California/USA)	508mm (533x)	52 Ori. Close but well split, near equal, ivory white. with apodising mask

STF3115

6^m.5

7^m.5

0.9"

337°

2017

Cam

05^h49^m04.64^s / +62°48'29.60"

Frederik Wanink

Itterbeck (Germany)

254mm (640x)

gerade eben trennbar mit schwarzem Zwischenraum

../projects/double-stars/frederik-wanink/sketches/STF3115.jpg

★★

BU1053

6^m.9

8^m.8

1.9"

0°

2019

Aur

05^h53^m28.64^s / +37°20'20.70"

Robert Zebahl Leipzig (Germany)	70mm (133x)	Border observation! Companion is temporarily visible in the correct position angle as an extremely dim brightening of the first diffraction ring of the primary component.
Mark McCarthy Fremont (California/USA)	317mm (270x)	Nice!! Blazing white and close but nicely split light blue B, 2 delta mag.

STT124

6^m.1

7^m.4

0.6"

299°

2018

Ori

05^h58^m53.23^s / +12°48'29.80"

Mark McCarthy Fremont (California/USA)	317mm (170x)	Seeing not good. Bloated yellow star with bluish B just attached to the edge, like a wart. B is very faint, small.
Mark McCarthy Fremont (California/USA)	317mm (553x)	Briefly split in the best moments, 1 second out of 10. A star yellow-white and small, hard blue B.

STT545, 37 Aur, theta Aur

2^m.6

7^m.2

4.2"

304°

2019

Aur

05^h59^m43.24^s / +37°12'45.90"

Robert Zebahl Leipzig (Germany)	70mm (57x)	At 57x nothing seen at first sight. At 133x the much fainter component was visible after a short time as a tiny star in the correct position angle. With this knowledge, the observation at 57x was also successful, even if one has to look very closely. The challenge here is not so much the angular distance as the large difference in brightness.
Uwe Pilz Leipzig (Germany)	105mm (200x)	blauweiß. Wegen der etwas unruhigen Luft und des Helligkeitsunterschiedes nicht einfach.
Mark McCarthy Fremont (California/USA)	178mm (222x)	Brilliant white A and light orange B, which is very much fainter and on the outside of A's third diffraction ring. A is causing a lot of diffraction in average to poor seeing. Physical with a 473 year period, it is now near apastron and will hang there for the rest of my lifetime

J335

8^m.4

9^m.5

1.1"

270°

2019

Ori

06^h04^m08.29^s / +11°00'57.00"

Mark McCarthy

Fremont (California/USA)

203mm (205x)

White A, B resolves with seeing, hairline split and two delta mag. Tough at this aperture

STT132

7^m.2

9^m.6

1.8"

332°

2012

Aur

06^h08^m11.68^s / +37°58'57.90"

Mark McCarthy

Fremont (California/USA)

317mm (270x)

White A and slightly red B. Fine pair. 2 delta mag.

KUI24

6^m.3

7^m.2

0.3"

144°

2014

Ori

06^h14^m28.59^s / +17°54'22.80"

Mark McCarthy

Fremont (California/USA)

508mm (667x)

Bright white, olive shape is the best I can see. Physical with 260-year period, it will tighten to invisibility the next 15 years

BU1008, eta Gem, 7 Gem, Propus

3^m.5

6^m.2

1.8"

258°

2020

Gem

06^h14^m52.69^s / +22°30'24.60"

Uwe Pilz Leipzig (Germany)	105mm (260x)	Aufhellung im ersten Ring
Uwe Pilz Leipzig (Germany)	105mm (288x)	sehr schwierig
Robert Zebahl Leipzig (Germany)	152mm (225x)	Already comparatively easy at 180x. The faint companion can be seen well as a quite distinct, slightly elongated, partly round brightening. At 225x and above it becomes easy and immediately apparent, even if the diffraction rings of the primary component are not permanently visible due to the seeing. The primary component was shining in a bright orange.
Mark McCarthy Fremont (California/USA)	203mm (333x)	Propus. Yellow A and blue-yellow B, 2 delta mag, 1.5" very nice

STF881, 4 Lyn

6^m.1

7^m.7

0.7"

149°

2020

Lyn

06^h22^m03.57^s / +59°22'19.50"

Frederik Wanink

Itterbeck (Germany)

254mm (640x)

schwierig wegen Helligkeitsunterschied

STF932

8^m.3

8^m.5

1.6"

305°

2019

Gem

06^h34^m21.57^s / +14°45'08.30"

Robert Zebahl Leipzig (Germany)	70mm (150x)	Unfortunately a nearby lamp bothered me. I could see the double star at least elongated.
Mark McCarthy Fremont (California/USA)	203mm (333x)	Very neat near equal white stars, well split

★★★

AGC1, 9 CMa, alpha CMa, Sirius

-1^m.5

8^m.4

11.2"

67°

2020

CMa

06^h45^m08.92^s / -16°42'58.00"

Uwe Pilz Leipzig (Germany)	105mm (198x)	mit ADV, ohne nicht trennbar. Eindeutig
Robert Zebahl Leipzig (Germany)	120mm (150x)	2021-03-02: Used magnifications from 86x to 200x using a Baader yellow filter. The diffraction disk was relatively good visible, but the diffraction rings were noticeably in movement (Seeing 3/5).
Jörg S. Schlimmer Germany	127mm (136x)	not split
Mark McCarthy Fremont (California/USA)	203mm (368x)	Small disk formed on diffraction spike at correct separation and PA (Feb. 2016)
Mark McCarthy Fremont (California/USA)	317mm (443x)	A faint yellow-orange disk, to the edge of Sirius A's diffraction and just below my spider's diffraction spike. I let Sirius pass beyond the field stop, and for an instant there was Sirius B, clearly separated, before it too passed beyond the field stop.

Jörg S. Schlimmer

Germany

305mm

hard to split with CMOS Camera

../projects/double-stars/joerg-schlimmer/photographs/Sirius_20210224_res_best45_bear.jpg

A122

8^m.9

9^m.4

0.4"

24°

2016

Gem

06^h45^m27.02^s / +29°21'59.80"

Mark McCarthy

Fremont (California/USA)

508mm (533x)

Nice light orange stars, hairline split with indifferent seeing, PA to the SW. Slight magnitude difference. Physical with 102.3-year period, I have the PA reversed in my estimate, it's to the NE -- still can claim it though. It is coming off apastron and will close slightly in the next 20 years. Aiken discovered in 1900 with the Lick 36-inch also at 0.4" -- 118 years since, so it has made a little more than one revolution

★★★

STF948, 12 Lyn

5^m.4

6^m.0

1.9"

65°

2020

Lyn

06^h46^m14.15^s / +59°26'30.10"

5^m.4

7^m.0

8.9"

309°

2019

Robert Zebahl Leipzig (Germany)	55mm (27x)	AC: Components A/B and C well separated, but tight. Significant difference in brightness. The fainter C companion appeared slightly orange, the brighter one white-bluish.
Robert Zebahl Leipzig (Germany)	55mm (167x)	AB: Components A and B separated, whereby the Airy disks slightly overlap. The difference in brightness was well visible.
Robert Zebahl Leipzig (Germany)	63mm (140x)	AB: Components A and B split with almost no space in between. The difference in brightness was visible.
Robert Zebahl Leipzig (Germany)	70mm (22x)	AC: Well split, relatively close together with significant difference in brightness.
Robert Zebahl Leipzig (Germany)	70mm (133x)	AB: Both components A + B clearly split, whereby the diffraction rings where merged together. A very nice view together with component C. I sketched this triplet, which reflects my impression well. Unfortunately, the distance and position angle are not particularly well observed. Also the difference in brightness I didn't noticed during my observation.
Robert Zebahl Leipzig (Germany)	102mm (129x)	At 28x the pair AC is nicely separated without any problems. The close pair AB is already recognizable at 86x as a clear figure '8', at 125x wonderfully separated. The components A & B appear yellowish. Very nice view together with STF 946 in one field of view!
Uwe Pilz Leipzig (Germany)	105mm (88x)	im selben Feld mit STF 946
Robert Zebahl Leipzig (Germany)	152mm (129x)	At 49x the pair AC is beautifully separated with a significant difference in brightness. At 100x, the close pair AB is also separated, although still very close together. A slight difference in brightness is noticeable. At 129x, the view is magnificent. The two bright components A & B present themselves yellowish, the fainter component C rather greyish. STF 948 can be well observed in a field of view with the neighbouring double star STF 946. Both show a nice overall scenery.
Mark McCarthy Fremont (California/USA)	178mm (148x)	AB: Gorgeous triple star, pale yellow A and B, and 1 delta blue C. really stunning. AB physical with a 733-year period

STT157

7^m.2

9^m.2

0.6"

161°

2018

Mon

06^h47^m47.56^s / +00°20'24.50"

Mark McCarthy

Fremont (California/USA)

317mm (277x)

Yellow A, widely separated from blue B. 2 magnitude difference. Did not notice 0.8" separation in A

★

STF958

6^m.3

4.5"

77°

2019

Lyn

06^h48^m12.29^s / +55°42'15.10"

Robert Zebahl Leipzig (Germany)	70mm (33x)	Clearly split, equally bright, close together. Nice view.
Robert Zebahl Leipzig (Germany)	102mm (62x)	Very nicely split. Both components appear similarly bright and white-yellowish.
Mark McCarthy Fremont (California/USA)	178mm (148x)	Near equal dull white typical Struve. Not much to look at but it's physical with a 2023 year period, with not much movement now but will whip around the A star pretty quickly when it reaches periastron 150 years from now

A2731

8^m.2

9^m.5

1.3"

67°

2016

Mon

06^h48^m39.38^s / +07°37'20.40"

Mark McCarthy

Fremont (California/USA)

178mm (205x)

Excellent pair, around 2 two delta mag, more than 1" separated, very fine, dull white A and light yellow B. Physical with a 247 year period

★

STF982, 38 Gem

4^m.8

7^m.8

7.3"

145°

2018

Gem

06^h54^m38.63^s / +13°10'40.10"

Robert Zebahl Leipzig (Germany)	55mm (27x)	At 27x pretty tight with much fainter component. At 71x clearly separated with clear difference in brightness. Brighter component appeared slightly yellowish, the weaker one slightly bluish.
Robert Zebahl Leipzig (Germany)	70mm (33x)	Easy to separated with noticeable difference in brightness. The fainter component appeared slightly orange, the brighter one rather white.
Uwe Pilz Leipzig (Germany)	105mm (130x)	recht attraktiv
Mark McCarthy Fremont (California/USA)	203mm (333x)	38 Gem. Light yellow A and blue B, quite wide, very pretty. AC much wider separation much fainter not noticed
Mark McCarthy Fremont (California/USA)	317mm (553x)	Bright orange and slightly red star, 2-3 delta mag.
Mark McCarthy Fremont (California/USA)	317mm (553x)	Pretty yellow and orange, 2 delta mag, wide separation

STF981

8^m.7

9^m.0

0.9"

119°

2016

Gem

06^h55^m28.54^s / +30°09'42.30"

Mark McCarthy Fremont (California/USA)	317mm (553x)	Very close orange pair, equal magnitude. Clean split, ~1".
Mark McCarthy Fremont (California/USA)	508mm (333x)	Very finely split, white stars, nearly 1 delta mag. Appeared as a rod at 205x. Physical with a 1089.7-year period. Discovered in 1831 at 3.7", near apastron, it has narrowed considerably since

STT159, 15 Lyn

4^m.5

5^m.5

0.7"

237°

2020

Lyn

06^h57^m16.60^s / +58°25'23.00"

Uwe Pilz Leipzig (Germany)	105mm (200x)	nicht getrennt im April 2020
Frederik Wanink Itterbeck (Germany)	254mm (640x)	relativ einfach

A1061 & STF1000

A1061

8^m.9

9^m.1

0.6"

42°

1999

Gem

06^h59^m21.15^s / +25°14'00.20"

STF1000

AB-C

8^m.1

9^m.0

22.1"

67°

2016

René Merting Drachhausen (Germany)	100mm (32x)	STF1000 (AB-C): bei 32x ein bequem getrenntes Pärchen - Komponente AB kühlweiß - Komponente C im Osten ist eine dreiviertel Größenklasse schwächer und grauweiß
Sarah Gebauer Germany	100mm (73x)	STF1000 (AB-C): sieht fast so aus, als hätte die westliche Komponente einen Gelbstich, bei 73x weit und deutlich getrennt
Robert Zebahl Leipzig (Germany)	152mm (30x)	STF1000 (AB-C): 2022-02-27: At 30x quite conspicuous, medium bright double star with nice separation. AB appears pale yellowish, the color of the slightly fainter companion C cannot be defined. The color impression remains even at 92x.

STT163

7^m.2

8^m.2

0.2"

115°

2011

Mon

07^h01^m09.85^s / +11°46'28.70"

Mark McCarthy

Fremont (California/USA)

317mm (553x)

Not perfectly round AB, a faint bluish haze in the diffraction to the south. Marginal

BU573

7^m.2

7^m.8

0.8"

311°

2018

Mon

07^h01^m49.89^s / -10°52'56.30"

Uwe Pilz Leipzig (Germany)	105mm (144x)
Uwe Pilz Leipzig (Germany)	105mm (247x)	schwach gekerbt

★

A2462

9^m.2

9^m.0

0.2"

246°

2020

Gem

07^h02^m37.42^s / +15°58'26.50"

Mark McCarthy

Fremont (California/USA)

508mm (1067x)

Short period list. Notched, noticeable magnitude difference, B star pointed in direction of apex of right triangle it forms with two other eighth magnitude stars. Light orange stars

STF1037

7^m.2

7^m.3

0.8"

304°

2019

Gem

07^h12^m49.08^s / +27°13'30.20"

Uwe Pilz Leipzig (Germany)	105mm (260x)	eingekerbt
Uwe Pilz Leipzig (Germany)	105mm (288x)	bei 200x trennbar, beide gelb
Mark McCarthy Fremont (California/USA)	178mm (205x)	Hairline split at 205x but went to 533x to get clear view of it to drift through the field to tell PA. Slight magnitude difference. Really nice looking pair, masked down to 7-inches to get clean disks. Physical with a 118.35-year period, it will close rapidly and become undetectable during the 2030s, widening again in the 2040s
Frederik Wanink Itterbeck (Germany)	254mm (640x)	leichter, gleich hell

STT170

7^m.4

7^m.7

0.6"

283°

2020

CMi

07^h17^m38.51^s / +09°17'31.50"

Mark McCarthy

Fremont (California/USA)

203mm (333x)

Notched, near equal at 333x. At 667x, hairline split very easy to see, near equal white stars

STF1066, delta Gem, 55 Gem

3^m.5

8^m.2

5.5"

229°

2018

Gem

07^h20^m07.39^s / +21°58'56.40"

Robert Zebahl Leipzig (Germany)	55mm (71x)	Large difference in brightness. The fainter component was well separated, but just a very tiny star.
Robert Zebahl Leipzig (Germany)	102mm (160x)	Easy to separate with relatively large distance. The companion appeared as a tiny, faint star.
Winfried Kräling Marburg (Germany)	102mm (178x)
Uwe Pilz Leipzig (Germany)	105mm (200x)	Nicht gesehen, wahrscheinlich ist der Begleiter zu schwach für leicht diesigen Himmel
Uwe Pilz Leipzig (Germany)	105mm (288x)	erster Ring in SSW heller, zweiter nur an dieser Stelle sichtbar
Mark McCarthy Fremont (California/USA)	178mm (205x)	Bright light yellow A and much fainter light orange B, wide about 6". Physical
Mark McCarthy Fremont (California/USA)	317mm (553x)	Wasat = Delta Geminorum: Pretty white-yellow and red-orange pair, PA to west, ~4".

★★★

STF1110, alpha Gem, 66 Gem, Castor

1^m.9

3^m.0

5.4"

53°

2020

Gem

07^h34^m35.86^s / +31°53'17.80"

1^m.9

9^m.8

71.6"

164°

2020

1^m.9

10^m.1

179.8"

221°

2017

Christopher Hay Seeheim (Germany)	20x60	AB: Handheld in reclining chair, binoculars with internal stabilisation. 16 April 2022 (5.5" angular distance according to database): Distinctly elongated, like a rectangle at the transition to a figure-8.
Christopher Hay Seeheim (Germany)	26x42	AB: 13 May 2022 (5.5" angular distance according to database). Moon four-fifths full a few degrees north of Spica in Virgo. 70mm binoculars stopped down to 42mm aperture. Directly after looking the Moon I was able to split Castor AB definitely. Could hold this for a full minute, only then did the split start to become uncertain. Repeated the observation several times, found the split to be definite each time.
Christopher Hay Seeheim (Germany)	32x70	AB: 13 March 2022 (5.5" angular distance according to database): Moon only 6° away and two-thirds full in the middle of Gemini. After concentrated observation of the Moon I slewed quickly to Castor to exploit the heightened acuity provided by viewing the bright Moon. Castor clearly split with fine black between A and B. After a while the split became more difficult but could still be held. Followed this up with the same eyepiece previously used in the achromatic 70/400 binoculars now placed in 71/400 fluorite apochromatic telescope, thus again yielding 32x. Again A and B split after observation of the Moon, but harder to hold with the mono apochromat than with the bino achromat.
Christopher Hay Seeheim (Germany)	36mm (33x)	AB: 16 April 2022 (5.5" angular distance according to database): With Käsemann (KSM) polarising filter at 33x two kissing Airy disks which seem to move apart in good moments, but this is uncertain. Without filter at 33x just a squat figure-8 far removed from separation. With polarising filter at 40x definite separation, fine first diffraction ring of component A. Without filter a stretched figure-8 with no separation. At 50x clear and stable separation with and without filter. Best view at 66x, a ghostly pair in pitch-black FOV, the first diffraction rings of A and B merging, that of B very faint. With a Baader Neodymium filter the positive effects are similar to those of the KSM polarising filter, but the clarity of separation is not quite as great as with the polarising filter.
Robert Zebahl Leipzig (Germany)	55mm (27x)	AB: At 27x slight difference in brightness visible. Double star appeared as '8'. At 38x clearly split, but tight.
Robert Zebahl Leipzig (Germany)	63mm (26x)	AB: Experiment to determine the smallest magnification to separate Castor. I observed on 2022-05-09, 2022-05-11 & 2022-05-18. At 26x and 30x easily seen as a double star, but not clearly separable due to outshining. At 70x of course easily separated. Stopped down to 30mm aperture, Castor appeared partially separated at 26x, but very barely. The right viewing position at the eyepiece was important. At 30x with 30mm aperture, Castor was cleanly separated, but extremely tight. Following a hint from Christopher Hay, I also used a red filter from Baader to avoid outshining at full aperture. Now also a separation at 26x was possible, whereby the components were extremely close to each other. For me a magnification of 26x seems to be the minimum to separate Castor cleanly, if the brightness of the components is reduced sufficiently.
Robert Zebahl Leipzig (Germany)	70mm (44x)	AB: At 44x the double star appeared as an '8'. At 100x clearly split with noticeable difference in brightness. Both components appeared white.
Christopher Hay Seeheim (Germany)	76mm (50x)	AB: 18 February 2021: At 23x oval-elongated with clear position of component A. At 50x finely split. At 83x best sight with first diffraction rings slightly overlapping. At 100x nice pattern of the Airy disks and the overlapping first and second diffraction rings of both components.
René Merting Drachhausen (Germany)	100mm (107x)	AB: bei 32x wirkt der Stern leicht länglich - bei 107x stehen die beiden Sterne schön eng mit überlagernden Beugungsscheibchen, die Komponenten sind dennoch getrennt erkennbar - Komponente B im Osten ist eine halbe Magnitude schwächer - ganz schwacher Farbkontrast
Uwe Pilz Leipzig (Germany)	105mm (144x)	AB: blauweiß-weiß
Winfried Kräling Marburg (Germany)	127mm (250x)	AB: 13.03.2017: Beide Komponenten gelblich mit geringem Helligkeitsunterschied, bereits bei V=60x getrennt.
Mark McCarthy Fremont (California/USA)	178mm (205x)	AB: Castor. A is a very pale yellow and B is yellow-green, 2 delta mag, very bright, pretty wide, some fainter stars about. Physical with a 459.8-year period
Christopher Hay Seeheim (Germany)	180mm (200x)	AB: Two fat spotlights in space. Component B seems greenish at first sight (using a first-class reflector free of chromatic aberration), and certainly has a different hue than component A. The second diffraction rings of A and B meet.

Frederik Wanink

Itterbeck (Germany)

254mm

../projects/double-stars/frederik-wanink/photographs/Castor.jpg

★★

STF1126

6^m.5

7^m.0

0.9"

176°

2019

CMi

07^h40^m06.99^s / +05°13'51.90"

Uwe Pilz Leipzig (Germany)	105mm (288x)	beide gelb. Es war schwierig, die hellere Komponente zu erkennen. Direkt neben Prokyon.
Mark McCarthy Fremont (California/USA)	317mm (553x)	Wow, very close <1" hair-split, near equal brightness

HO247

7^m.7

9^m.2

0.5"

257°

2012

Gem

07^h46^m07.95^s / +21°07'19.20"

Mark McCarthy

Fremont (California/USA)

508mm (533x)

Clean split with seeing, 1 delta mag, fairly bright pair. I found the apodizing mask worked better than the 8-inch mask, gave more resolving power. The 8-inch was only snowman

WRH15, 82 Gem

6^m.8

7^m.3

0.3"

28°

2016

Gem

07^h48^m33.65^s / +23°08'27.50"

Mark McCarthy

Fremont (California/USA)

508mm (1067x)

82 Gem. I see an elongated misshape, PA to the NNE, but not firm. Physical with a 580-year period. R.H. Wilson

★

BU101, 9 Pup

5^m.6

6^m.5

0.4"

307°

2019

Pup

07^h51^m46.31^s / -13°53'52.80"

Mark McCarthy

Fremont (California/USA)

508mm (1067x)

9 Pup. Elongated to notched, orientation correct, light orange. Very tough. [B is coming off it's furthest orbit and will be exceptionally difficult in 10 years, but easier in 15 years]

STT182

7^m.8

7^m.9

0.9"

9°

2017

CMi

07^h52^m42.12^s / +03°23'02.20"

Mark McCarthy Fremont (California/USA)	203mm (333x)	Compact white pair, more near equal than Sky Tools says, white, easy split
Mark McCarthy Fremont (California/USA)	317mm (553x)	Very close, ~1", near equal brightness white.

★

STT185

7^m.1

7^m.3

0.4"

22°

2020

CMi

07^h57^m16.39^s / +01°07'37.30"

Mark McCarthy

Fremont (California/USA)

508mm (1067x)

Without the apodizing mask I get a clean split with seeing but constant split with the mask. Light orange stars, noticeable mag difference

★

BU581

8^m.5

8^m.8

0.4"

226°

2018

Cnc

08^h04^m23.10^s / +12°17'23.80"

Mark McCarthy Fremont (California/USA)	317mm (553x)	Light orange near equal, very small, elongated to notched.
Mark McCarthy Fremont (California/USA)	508mm (1067x)	With apodizing mask. Beautiful clean split, almost wide, light orange stars, slight mag difference. There is a third 2x fainter star further out, might be plus one. Wow. [3rd is AB-C, 8.46/11.78 5.5"]

STF1187

7^m.2

8^m.0

3.1"

21°

2020

Cnc

08^h09^m30.45^s / +32°13'18.80"

Robert Zebahl Leipzig (Germany)	70mm (57x)	Split. Components very tight with noticeable difference in brightness.
Mark McCarthy Fremont (California/USA)	178mm (205x)	White stars, a little more than 1 delta mag, wide about 4". Physical with a 1385.156-year period
Mark McCarthy Fremont (California/USA)	317mm (553x)	Yellow and orange, 1 delta mag, 5"
Karsten Kopp Köln (Germany)	600mm (180x)	Noch gut zu trennender Doppelstern mit leichtem Helligkeitsunterschied. Komponente A leuchtet gelblich weiß und Komponente B gelb.

★★★

zeta Cnc, 16 Cnc

STF1196

5^m.3

6^m.2

1.2"

2°

2020

Cnc

08^h12^m12.79^s / +17°38'51.20"

STF1196

AB-C

4^m.9

5^m.8

6.0"

64°

2020

STF1196

5^m.3

5^m.8

6.2"

62°

2020

HUT1

Ca-Cb

6^m.2

7^m.1

0.3"

8°

2020

Robert Zebahl Leipzig (Germany)	70mm (133x)	The wide pair AB-C is already separable at 22x. The pair AB shows at 133x two clearly overlapping diffraction disks with small difference in brightness, but without any notch.
Christopher Hay Seeheim (Germany)	71mm (32x)	AB-C: Finely split. AB yellowish. Substantial delta-mag.
Robert Zebahl Leipzig (Germany)	102mm (86x)	AB-C: Easy to separate. A: light grey, B: pale orange.
Stefan Loibl Rosenheim (Germany)	102mm (164x)	AB-C clearly split, AB obviously elongated but not split
Uwe Pilz Leipzig (Germany)	105mm (288x)	weißblau-gelb-gelb
Robert Zebahl Leipzig (Germany)	120mm (67x)	AB-C: Evident difference in brightness, easy to split. Both components of similar color.
Robert Zebahl Leipzig (Germany)	120mm (200x)	AB: Very tight. The Airy disks were still touching. Slight difference in brightness. Extremely beautiful triple star!
Winfried Kräling Marburg (Germany)	127mm (250x)	08.04.2018: Sehr schön, 3-fach Stern, A = weißgelb, B = weißgelb, C = weißgelb
Sarah Gebauer Germany	150mm (83x)	AB-C: bei 83x sind AB-C sauber getrennt, laut Atlas 2020 6,1'' Abstand, die Komponenten A und B mit 1,1'' lassen sich nicht trennen, viele schöne Feldsterne dabei
Christopher Hay Seeheim (Germany)	180mm (200x)	AB: Hair-fine split. A and B both yellowish-white. C wide from AB, bluish-white, nice colour contrast to AB.
Frederik Wanink Itterbeck (Germany)	254mm (200x)	AB-C: AB (1,1") nicht bemerkt
Mark McCarthy Fremont (California/USA)	317mm (553x)	Ca-Cb: not quite round, oval/olive shaped. It is the AB-C of STF 1196.
Mark McCarthy Fremont (California/USA)	317mm (553x)	AB: Triple, all near equal magnitude, yellow-white. AB ~0.8", hair split.
Mark McCarthy Fremont (California/USA)	317mm (553x)	AC: Triple, all near equal magnitude, yellow-white. AC ~6", wide split.
Karsten Kopp Köln (Germany)	600mm (257x)	AB: Die Komponenten AB-C bei etwas größerem Helligkeitsunterschied einfach zu trennen und auch schön anzusehen. Sterne erstrahlen weißlich gelb. Komponente AB war nicht zu trennen.

★

A1746, 24 Cnc

8^m.5

0.2"

4°

2007

Cnc

08^h26^m39.82^s / +24°32'03.70"

Mark McCarthy

Fremont (California/USA)

508mm (1067x)

Component of STF1224. I see a very subtle notched elongation, PA SSW, noticeable mag difference. Physical with a 21.78-year period, it is a nearly circular orbit and near periastron, it's apastron will be in 2029 at 0.16"

HU714

Ba-Bb

9^m.8

10^m.1

0.8"

313°

2012

Cnc

08^h26^m56.47^s / +32°11'47.30"

Mark McCarthy

Fremont (California/USA)

508mm (533x)

Nicely split with seeing, 0.5-1.0 delta mag, 0.5" separation. Short period of 195.5 years, it is at apastron now and will remain there the rest of my lifetime

★

A551, LO Hya

7^m.0

7^m.1

0.4"

63°

2018

Hya

08^h28^m29.16^s / -02°31'01.60"

Mark McCarthy

Fremont (California/USA)

508mm (1067x)

LO Hya. With apodizing mask. Easy split, noticeable half delta mag. Another fainter star further out likely +1 [The +1 is STF 1233 AB-C, 6.42/10.49 18.3". AB at furthest extent of orbit, will tighten considerably the next 20 years]

AG154

9^m.6

9^m.8

2.7"

1°

2019

Cnc

08^h36^m55.78^s / +23°14'49.10"

Mark McCarthy

Fremont (California/USA)

508mm (533x)

HO Cnc. Near equal well separated, light orange stars

★★★

11 Hya, epsilon Hya

SP1

3^m.5

5^m.0

0.2"

241°

2018

Hya

08^h46^m46.51^s / +06°25'07.70"

STF1273

AB-C

3^m.5

6^m.7

2.9"

311°

2020

STF1273

AB-D

3^m.5

12^m.5

18.1"

201°

2017

STF1273

AB-E

3^m.5

10^m.8

340.5"

2°

2015

STF1273

AB-F

3^m.5

10^m.4

406.5"

265°

2015

Robert Zebahl Leipzig (Germany)	70mm (133x)	AB-C: Not split. Although a slight brightening was visible in the first diffraction ring, it could also have come from slight coma of the refractor.
Sarah Gebauer Germany	100mm (200x)	AB-C: ist ein heller Stern vom Hydra-Kopf, nicht zu trennen, vermutlich, weil die Komponente AB zu hell strahlt
Robert Zebahl Leipzig (Germany)	102mm (160x)	AB-C: 2020-03-27: The much fainter companion is well visible as an almost round knot directly at the diffraction ring of the primary component. Very nice sight. The seeing was mediocre (3/5).
Uwe Pilz Leipzig (Germany)	105mm (200x)	AB-C: bei 144x schwierig
Robert Zebahl Leipzig (Germany)	152mm (150x)	AB-C: 2020-03-27: The companion is immediately visible as a tiny star close to the primary component. Due to the chromatic aberration of the achromat, there is a slight tendency to outshine. Nevertheless a nice view. The seeing was mediocre (3/5).
Mark McCarthy Fremont (California/USA)	508mm (533x)	AB-C: Epsilon Hya A is bright orange-yellow, B is much fainter and a little blue, ~3". [SP 1 AB is 3.49/5.00 0.2" not seen]

★

A2552

9^m.1

8^m.5

0.3"

208°

2018

Hya

08^h48^m40.30^s / +00°56'31.00"

Mark McCarthy

Fremont (California/USA)

508mm (533x)

Wow fine split. Pale yellow A and blue B, about one delta mag. Nice split, amazing [82.4 year period]

VDK3

9^m.9

10^m.1

1.0"

199°

2020

Cnc

08^h50^m42.33^s / +07°51'52.40"

Mark McCarthy

Fremont (California/USA)

508mm (410x)

With apodising mask. A surprise short period find. Light orange stars -- they are carbon, HP Cnc. About 1 delta mag, more than 1" separation. Seeing is bloating the stars a bit, but can recorded the PA by drift, it follows a S-N line. J. Vanderdonck, who has three discoveries to his name in the WDS. Physical with a 223.9709-year period, it will make a quarter turn by 2040

STF1282

7^m.6

7^m.8

3.5"

279°

2019

Lyn

08^h50^m44.28^s / +35°04'15.40"

Robert Zebahl

Leipzig (Germany)

70mm (57x)

Clearly separated, but close together with very little difference in brightness. The double star forms an acute-angled triangle together with two other stars.

A1584

9^m.0

7^m.7

0.6"

94°

2018

UMa

08^h53^m08.05^s / +54°57'11.00"

Mark McCarthy

Fremont (California/USA)

508mm (333x)

Tight white stars, seeing is not very good but can still split it. It has a noticable magnitude difference, however I need to guess which one is A. I am able to estimate PA by drifting it across the field. [My PA is in the correct line but my A and B are reversed.] 70.89-year period, it is now at apastron and will make a very small turn in its arc by 2040

★

STF1291, 57 Cnc

6^m.1

6^m.4

1.5"

310°

2019

Cnc

08^h54^m14.65^s / +30°34'45.80"

AB-C

5^m.5

9^m.2

54.6"

204°

2015

Robert Zebahl Leipzig (Germany)	70mm (133x)	AB: Immediately apparent as a double star. Diffraction disks overlapping slightly ('8'). Difference in brightness visible.
Uwe Pilz Leipzig (Germany)	105mm (144x)	gelb
Sarah Gebauer Germany	150mm (125x)	AB: sowohl bei 83x als auch bei 125x knapp vorm Trennen
Mark McCarthy Fremont (California/USA)	203mm (205x)	AB: 57 Cnc. Very nice pair, strong orange yellow colors, ~1 delta mag, bright, nice close split

AG338

9^m.0

9^m.2

2.1"

164°

2020

Cnc

08^h54^m41.52^s / +16°36'39.70"

Mark McCarthy

Fremont (California/USA)

508mm (148x)

IK Cnc. White stars, near equal, well split. Physical with a 1790-year period. A is TOK 196 0.2", not attempted, with just a 15-year period, need to go back!

STF1280

8^m.8

9^m.1

3.5"

359°

2020

UMa

08^h55^m24.82^s / +70°47'39.20"

8^m.8

12^m.4

398.4"

88°

2015

9^m.1

12^m.4

398.5"

88°

2015

Robert Zebahl Leipzig (Germany)	70mm (67x)	AB: 2021-04-03: Rather faint double star with components still pretty close together and little difference in brightness.
René Merting Drachhausen (Germany)	100mm (72x)	AB: ein knapp getrenntes Sternpaar - beide Sterne sind annähernd gleich hell und strahlen rein weiß - bei 144x eine ordentlichere Trennung, Komponente A im Süden strahlt in einem wärmeren Weiß

iota UMa, 9 UMa, Talitha

HJ2477

A-BC

3^m.1

9^m.2

2.4"

90°

2017

UMa

08^h59^m12.45^s / +48°02'30.60"

HU628

9^m.9

10^m.1

0.9"

206°

2017

Robert Zebahl Leipzig (Germany)	152mm (300x)	A-BC: 2020-04-24: The seeing (3/5) was not good enough for a split.
Mark McCarthy Fremont (California/USA)	508mm (213x)	A-BC: Iota UMa = Talitha. Using 25mm occulting bars with barlow, no mask, putting the bright star's diffraction spikes under the bars, I can see the hard point of the B star, brighter & closer than Procyon B outside of A's glare. One other field star. [HJ 2477's period is 2735 years. The short period is BC is HU 628 9.90/10.10 0.9" 39 year period -- how in the world did he see that?]

STF1300

9^m.5

9^m.7

5.0"

178°

2020

Cnc

09^h01^m17.48^s / +15°15'56.80"

Mark McCarthy

Fremont (California/USA)

508mm (148x)

Very light orange stars, one more white than the other, well separated, near equal. Physical with 878-year period

★★

STF1306, sigma 2 UMa, 13 UMa

4^m.9

8^m.8

4.4"

346°

2020

UMa

09^h10^m23.53^s / +67°08'03.30"

4^m.9

10^m.3

197.8"

148°

2003

Robert Zebahl Leipzig (Germany)	70mm (100x)	AB: Companion almost permanently visible as elongated, non-condensed brightening of the first diffraction ring of the primary component at the correct position angle.
Christopher Hay Seeheim (Germany)	76mm (20x)	AB, April 2021: No luck with AB at all magnifications from 83x to 167x. AC: Component C very faint and quite distant, not really seeming to belong.
Mark McCarthy Fremont (California/USA)	80mm (150x)	AB: Suspected very close unequal white stars. 920-year period, slowly widening
Uwe Pilz Leipzig (Germany)	105mm (144x)	AB: sehr schwierig bei 88x

★★

STF1321

7^m.8

7^m.9

16.9"

99°

2019

UMa

09^h14^m22.79^s / +52°41'11.80"

7^m.8

14^m.5

145.7"

64°

2010

7^m.8

11^m.9

136.4"

129°

2015

Robert Zebahl Leipzig (Germany)	16x70	AB: 2020-07-05: Very nice view, striking, easily separable. A slight difference in brightness is visible. At first glance the double star appeared noticeably orange compared to the surrounding stars, on closer look a color difference of the two components was visible: orange & rather white.
Robert Zebahl Leipzig (Germany)	70mm (22x)	AB: 2020-04-11: At 22x pretty wide pair with equally bright components. Striking colors: slightly orange & white-bluish, but it was a bit difficult to assign the colors to the components. At 44x slightly better color perception.
Robert Zebahl Leipzig (Germany)	70mm (31x)	AB: 2020-04-19: Together with STF1312 in one field of view. At 22x very nice sight, easy to separate, attractive separation. Immediately apparent. A color difference is visible: dark yellow, orange. Also beautiful to see at 44x. Best view at 31x.
Christopher Hay Seeheim (Germany)	71mm (32x)	AB: April 2021: Well split, matched pair. Both orangish. With 180mm at 200x a wide, even, strong pair. Component A is noticeably slightly brighter. Both of identical pale mandarine-orange colour, rather captivating.

STF1332

7^m.9

8^m.1

5.9"

29°

2019

Cnc

09^h17^m19.21^s / +23°39'09.80"

Christopher Hay Seeheim (Germany)	100mm (44x)	Clearly split, a little tighter and much less striking than nearby STF 1311 (two degrees to NSW). STF 1332, at a distance to us 233 light years, has the benefit of a documented orbit, while STF 1311, 190 light years distant, is a common proper motion pair. Hence two physical pairs reasonably close both in the plane of our sky and in actual space.
Mark McCarthy Fremont (California/USA)	203mm (333x)	Near equal wide pair, ~5", maybe half delta mag

★

STF3121

7^m.9

8^m.0

0.5"

210°

2019

Cnc

09^h17^m53.45^s / +28°33'37.70"

Mark McCarthy Fremont (California/USA)	508mm (533x)	IP Cnc Split at 533x, used 1067x to recheck orientation. With apodizing mask. Light yellow-orange stars, nice and clean split, very slight mag difference. Real nice
Mark McCarthy Fremont (California/USA)	508mm (533x)	IP Cnc. Light yellow-orange stars, 1 delta mag, clean well split. 34.17-year period, it's coming off apastron and will make a quarter turn by 2030. PA to the NE

★

HO43

9^m.3

9^m.5

0.6"

98°

2017

Cnc

09^h18^m36.25^s / +20°48'49.40"

Mark McCarthy

Fremont (California/USA)

508mm (410x)

Fine white stars, not quite 1 delta mag, very nice clean split. Wow. Physical with 358.6-year period, it will widen a couple tenths in the next 20 years

★

STF1334, 38 Lyn

3^m.9

6^m.1

2.6"

224°

2019

Lyn

09^h18^m50.64^s / +36°48'09.30"

Uwe Pilz Leipzig (Germany)	60mm (198x)	Aufhellung im ersten Ring
Robert Zebahl Leipzig (Germany)	63mm (140x)	Fainter companion only seen as permanent brightening on the first diffraction ring.
Christopher Hay Seeheim (Germany)	71mm (32x)	Figure-8 with clear positions and delta-mags of components. Bluish-white.
Uwe Pilz Leipzig (Germany)	105mm (288x)	gelb, trennbar bei 66x
Mark McCarthy Fremont (California/USA)	178mm (205x)	Very bright light blue A and 3 delta magnitude greenish B, close, about 3" separation. Physical with 2782 year period
Christopher Hay Seeheim (Germany)	180mm (113x)	Clean split, large delta-mag. Separation ca. 1.5 times that of nearby STF1333.

STF1338

6^m.7

7^m.1

1.2"

314°

2020

Lyn

09^h20^m59.40^s / +38°11'17.90"

Mark McCarthy

Fremont (California/USA)

508mm (333x)

Wonderful light yellow stars, near equal, ~1" separation

STT201

8^m.5

9^m.5

1.4"

206°

2017

Leo

09^h23^m54.55^s / +27°53'54.90"

Mark McCarthy

Fremont (California/USA)

203mm (205x)

Extremely fine split, with seeing only, finest of the night, significant mag difference, just above 1" separation

★★

STF1348

7^m.5

7^m.6

2.0"

314°

2018

Hya

09^h24^m28.48^s / +06°21'01.80"

Robert Zebahl Leipzig (Germany)	70mm (100x)	2020-04-10: At 67x clearly elongated, at 80x clearly visible as figure '8'. At 100x a very small difference in brightness was to be guessed, at 133x visible. Near the double star STF 1355.
Uwe Pilz Leipzig (Germany)	105mm (144x)	Im selben Aufsuchfeld wie stf1355, ähnliche Erscheinung
Mark McCarthy Fremont (California/USA)	203mm (333x)	Very pretty half delta mag, ~2" pair, white. Sharp despite low declination

A2477

7^m.5

9^m.2

0.5"

5°

2016

Leo

09^h24^m31.21^s / +18°08'29.10"

Mark McCarthy

Fremont (California/USA)

178mm (410x)

Notched elongation, slight magnitude difference, light yellow stars. Physical with a 250 year period in a nearly circular orbit (we see it face-on)

A222

9^m.1

9^m.4

0.4"

5°

2017

Leo

09^h26^m02.33^s / +28°39'01.50"

Mark McCarthy

Fremont (California/USA)

508mm (667x)

Suspect it at all powers up to 667x, where I get a persistent clean split through the seeing. Light orange stars, 1 delta, PA just east of north. 155.08-year period, it will only cross the north line to head west by 2030

★★

STF1355

7^m.7

7^m.8

1.8"

357°

2018

Hya

09^h27^m16.69^s / +06°13'59.00"

Robert Zebahl Leipzig (Germany)	70mm (100x)	2020-04-10: At 67x clearly elongated, equally bright. At 80x detectable notch. At 100x and 133x clearly visible as figure '8'. Near the double star STF 1348.
Uwe Pilz Leipzig (Germany)	105mm (144x)	Im selben Aufsuchfeld wie stf1348, ähnliche Erscheinung
Mark McCarthy Fremont (California/USA)	203mm (333x)	Light yellow pair, near equal, very nice, ~2"

HU1128, 11 LMi

4^m.8

12^m.5

7.1"

59°

2016

LMi

09^h35^m39.50^s / +35°48'36.40"

Mark McCarthy

Fremont (California/USA)

317mm (553x)

11 LMi: Very faint A & extremely faint B, wide separation. From the orbital chart this is approaching maximum elongation now (May 2017), by 2143 it will be 1". Only 39 light years away.

★

STF1362

7^m.0

7^m.2

4.9"

125°

2017

Dra

09^h37^m56.18^s / +73°04'49.50"

Robert Zebahl

Leipzig (Germany)

70mm (31x)

2020-04-21: At 22x extremely tight, but separable. At 31x very fine separation. Both components appeared white. Very nice sight! At 57x well separated, similarly bright. One component appeared white-yellowish with a hint of orange, the other more white.

STF1374

7^m.3

8^m.7

2.8"

312°

2019

LMi

09^h41^m21.88^s / +38°57'01.90"

Robert Zebahl Leipzig (Germany)	70mm (100x)	2020-04-01: Separable at 67x, but difficult due to the bright primary component. Clearly separable at 80x and higher magnifications with a significant difference in brightness. The companion stands close to the primary component and appears as a tiny star. Nice view.
Robert Zebahl Leipzig (Germany)	120mm (168x)	At 50x elongated, at 75x seen as '8'. At 168x clearly split with obviously fainter component.
Mark McCarthy Fremont (California/USA)	508mm (333x)	Pretty orange-yellow stars, ~2 delta mag, ~3 separation
Karsten Kopp Köln (Germany)	600mm (180x)	Doppelstern ist gut zu trennen, mit klarem Helligkeitsunterschied. Beide Sterne erstrahlen weißlich.

HO369

8^m.0

9^m.8

0.3"

284°

2020

LMi

09^h51^m09.34^s / +36°29'20.80"

Mark McCarthy

Fremont (California/USA)

508mm (1067x)

With 533x I can tell this is not single, but the elongation is too tentative. At 1067x the best I can manage is elongated notched, with seeing. Seeing and transparency are not good enough

★

STF1381

8^m.9

9^m.2

0.8"

187°

2017

UMa

09^h51^m15.22^s / +60°37'00.10"

Mark McCarthy

Fremont (California/USA)

178mm (205x)

Finest split with seeing, very small scale at this magnification, light orange star, very significant magnitude difference. Physical with a 1787.6479-year period, this is actually one to watch because it is rapidly nearing periastron and will tighten over the next couple of decades

★

STT208, phi UMa

5^m.3

5^m.4

0.4"

315°

2019

UMa

09^h52^m06.36^s / +54°03'51.40"

Uwe Pilz Leipzig (Germany)	105mm (260x)	länglich, schwierig
Mark McCarthy Fremont (California/USA)	178mm (333x)	Tough in poor seeing and transparency. Bright white A, significant delta magnitude, B's PA a little north of west. There are three stars in a wide triangle in the field, B points to base line. Physical with 104.6-year period, it will widen slightly and will reach apastron by 2040
Christopher Hay Seeheim (Germany)	180mm (290x)	4 April 2021 (0.43" angular distance according to database at time of observation): At 200x seems oval. At 290x definite elongation and clear position angle. My personal record for double-star detection and PA perception with the seven-inch telescope.

STF1389

9^m.1

9^m.5

2.4"

290°

2019

Leo

09^h52^m26.17^s / +26°58'53.80"

Mark McCarthy

Fremont (California/USA)

178mm (205x)

White stars, around 1 delta mag, well separated. Physical with a 1454-year period

AC5, gam Sex

5^m.4

6^m.4

0.5"

38°

2019

Sex

09^h52^m30.47^s / -08°06'17.70"

Mark McCarthy

Fremont (California/USA)

508mm (533x)

Gamma Sex: I get a split with seeing of nearly equal orange yellow stars, only momentarily

STF1394

8^m.9

9^m.8

4.5"

250°

2019

UMa

09^h57^m14.57^s / +45°54'10.10"

Mark McCarthy

Fremont (California/USA)

178mm (205x)

White stars, >1 delta mag, wide about 5". Physical

HU874

6^m.9

7^m.9

0.2"

288°

2019

Leo

10^h11^m38.19^s / +13°21'18.70"

Mark McCarthy

Fremont (California/USA)

508mm (1067x)

34 Leo. A notched elongation is the best I could see, not resolved well. Slight mag difference but really too hard to tell A from B. My PA estimate is off 90-degrees. This is rapidly closing and will be at periastron by the middle of 2022, opening again and should be better detectable again by 2029 when it will be 0.208". 17.962-year period

STT213

8^m.6

9^m.8

1.1"

125°

2019

Leo

10^h13^m08.88^s / +27°25'10.50"

Mark McCarthy Fremont (California/USA)	178mm (333x)	Very tough at this aperture, I suspected it at 205x but can more consistently see it with 333x. A is a light orange star and B splits but is very tight, needed averted vision at first but it brightens and holds with foveal coaxing, but it s very faint indeed. Physical with a 192-year period, it's now at apastron and will stay there a while
Mark McCarthy Fremont (California/USA)	317mm (277x)	Bright yellow A, ~2 magnitudes fainter B, very wide separation.

STT215

7^m.2

7^m.5

1.5"

176°

2019

Leo

10^h16^m16.05^s / +17°44'24.60"

Robert Zebahl Leipzig (Germany)	70mm (133x)	Appeared partly separated, partly as '8'. Brightness seemed to be equal.
Uwe Pilz Leipzig (Germany)	105mm (288x)	trennbar bei 120x
Mark McCarthy Fremont (California/USA)	317mm (277x)	very close split (1.7" separation) near equal bright white stars
Mark McCarthy Fremont (California/USA)	508mm (333x)	Near equal light yellow stars, ~1.5"

★

STF1423

9^m.4

10^m.1

0.7"

308°

2018

Leo

10^h19^m10.64^s / +20°33'48.10"

Mark McCarthy Fremont (California/USA)	317mm (553x)	Tough! Elongated to hairline split.
Mark McCarthy Fremont (California/USA)	508mm (533x)	Split with seeing, light orange A and very faint, ~3 delta mag B, very close, within diffraction ring <1"

★★

STF1424, gamma Leo, 41 Leo, Algieba

2^m.4

3^m.6

4.7"

127°

2020

Leo

10^h19^m58.35^s / +19°50'29.40"

Christopher Hay Seeheim (Germany)	20x60	Handheld in reclining chair, binoculars with internal stabilisation. 14 May 2022 (4.7" angular distance according to database): Pear-shaped. Strong orange-lemon yellow, a fruity affair. PA estimated 140° without prior knowledge, a good enough match, considering the low magnification, to the database figure of 127° ascertained post-observation.
Christopher Hay Seeheim (Germany)	44x100	21 May 2022 (4.7" angular distance according to database): Hairfine split, slightly difficult due to bloated stars in these achromatic (not apochromatic) binoculars. Both components orange, with secondary going into yellow. Thin cloud moving through tightens up the star images and makes the split much clearer. Clearest shortly before clouds become so dense as to swallow the pair.
Christopher Hay Seeheim (Germany)	36mm (50x)	21 May 2022 (4.7" angular distance according to database): At 40x deeply notched, at 50x tenuously split, at 66x cleanly and clearly split.
Robert Zebahl Leipzig (Germany)	55mm (38x)	At 38x split, but very tight with noticeable difference in brightness. At 56x and higher beautiful view of both components, which seemed to have similar colors.
Robert Zebahl Leipzig (Germany)	55mm (59x)	Very nice unequal double. A appeared yellow-orange, B rather white-bluish.
Christopher Hay Seeheim (Germany)	60mm (58x)	At 25x Algieba is already very elongated. At 58x a sliver of dark between the components, with clear brightness difference. At 70x split becomes more stable, but view not so pleasing as at 58x. Both components display vivid orange.
Robert Zebahl Leipzig (Germany)	70mm (100x)	At 67x still a relatively close pair, but well separated with quite a clear difference in brightness. At 100x easy to separate and visible color difference: A yellowish to slightly orange, B white-yellowish.
Robert Zebahl Leipzig (Germany)	102mm (125x)	Very nicely separated with wonderful contrast in brightness and color. Primary component slightly orange, companion yellowish.
Stefan Loibl Rosenheim (Germany)	102mm (164x)	very bright double star, slight colour contrast
Uwe Pilz Leipzig (Germany)	105mm (120x)	schon bei 37x sehenswert; trennbar bei 55x; orange-blauweiß
Robert Zebahl Leipzig (Germany)	120mm (66x)	At 48x easily seen as double star. It appeared as '8'. At 66x pretty tight with visible difference in brightness.
Winfried Kräling Marburg (Germany)	127mm (250x)	08.04.2018: merklicher Helligkeitsunterschied, A = gelb-orange, B = gelb-orange
Sarah Gebauer Germany	150mm (83x)	bei 83x sauber getrennt, ein leichter Farbunterschied (Weiß und helles Gelb) sichtbar
Mark McCarthy Fremont (California/USA)	317mm (277x)	Algieba: Bright yellow and yellow-orange pair, 1 delta mag, 4-6"
René Merting Drachhausen (Germany)	320mm (240x)	bei 240x sehe ich zwei ordentlich getrennte Sterne (naja, nicht wirklich Sterne, sondern wild zappelnde Glitzerbällchen) - Komponente A strahlt in einem zarten Gelb, B ist weiß - zurück auf 144x sehe ich nur ein Stäbchen mit leichter Einschnürung, so wild tanzen die Sterne
Mark McCarthy Fremont (California/USA)	508mm (333x)	Algieba. Very bright, A is yellow-orange and B is a blazing white orange, like a fire

★

STF1426

8^m.0

8^m.3

0.9"

313°

2018

Leo

10^h20^m32.32^s / +06°25'47.60"

AB-C

7^m.3

9^m.4

7.6"

9°

2018

René Merting Drachhausen (Germany)	100mm (107x)	AB: bei 213x in guten Momenten als Stäbchen erkennbar AB-C: bei 107x ist nördlich vom Hauptstern AB eine gut 2 Größenklassen schwächere Komponente erkennbar - AB ist weiß, C ist grau
Robert Zebahl Leipzig (Germany)	102mm (160x)	AB-C: Quite large angular distance and therefor easy to separate. The C component was pretty faint.
Robert Zebahl Leipzig (Germany)	102mm (160x)	AB: At first glance elongated, on closer look visible as '8'.
Stefan Loibl Rosenheim (Germany)	102mm (164x)	AB-C easily split, A-B not detectable as double
Uwe Pilz Leipzig (Germany)	105mm (288x)	A-B länglich, C weit
Mark McCarthy Fremont (California/USA)	203mm (333x)	AB: Split with seeing, white, very close, near equal. Part of plus one, a two delta mag not far away

★★

STT216

7^m.4

10^m.3

2.3"

231°

2016

Leo

10^h22^m43.81^s / +15°20'39.70"

Mark McCarthy Fremont (California/USA)	317mm (277x)	A white and bright (7.3), B red & much fainter (10.3), a close split (2").
Mark McCarthy Fremont (California/USA)	508mm (333x)	Yellow and very much fainter orange B, 1 delta mag, ~4" separated

★

STF1429

9^m.1

9^m.3

0.8"

155°

2017

Leo

10^h25^m01.79^s / +24°36'44.10"

Mark McCarthy Fremont (California/USA)	317mm (553x)	Very tough. Faint, need averted vision to brighten and sharpen. Elongated to clean split in the best moments with seeing, near equal magnitude
Mark McCarthy Fremont (California/USA)	508mm (533x)	Elongated to hairline at 333x, split at 533x. Light orange stars, near equal

★

STT217

7^m.8

8^m.6

0.8"

151°

2019

Leo

10^h26^m53.01^s / +17°13'09.90"

Mark McCarthy

Fremont (California/USA)

508mm (333x)

Just split cleanly, ~1 delta mag, yellow-tinged white stars. Nice close pair

★

STF1439

8^m.3

8^m.9

1.4"

73°

2019

Leo

10^h30^m06.42^s / +20°48'04.30"

Mark McCarthy

Fremont (California/USA)

508mm (333x)

Very clean images, light yellow-orange stars, ~1 delta mag, well split, very pretty

★

STF1454

9^m.0

11^m.0

1.3"

358°

2016

LMi

10^h38^m11.10^s / +26°36'24.80"

Mark McCarthy

Fremont (California/USA)

317mm (553x)

Quite tough: averted vision only, very tight, similar magnitude, when seeing stills.

STF1457

7^m.7

8^m.2

1.9"

334°

2019

Sex

10^h38^m43.14^s / +05°44'02.90"

René Merting Drachhausen (Germany)	100mm (142x)	bei 107x sehe ich in guten Momenten eine Stäbchen, manchmal auch schon leichte Einschnürungen - bei 142x zeigt sich das Sternpaar deutlich als 8 und mit etwas Geduld auch getrennt - B steht im NO und ist eine halbe Größenklasse schwächer - bei 213x dann eindeutige Trennung
Mark McCarthy Fremont (California/USA)	508mm (333x)	Attractive bright sunny yellow pair, more than 2" separation, slight mag difference

A2768

6^m.9

8^m.4

0.6"

238°

2019

Sex

10^h42^m37.53^s / +03°34'58.90"

Mark McCarthy Fremont (California/USA)	317mm (277x)	Feels like a not round disk, but uncertain.
Mark McCarthy Fremont (California/USA)	508mm (533x)	34 Sex. Surprisingly difficult. Light orange A and a very small 2 delta mag pin prick appears within the first diffraction ring, so about 0.5" separation. Very tough. With seeing only

A2771

9^m.2

9^m.7

0.6"

112°

2018

Sex

10^h44^m38.71^s / +05°29'55.00"

Mark McCarthy

Fremont (California/USA)

508mm (533x)

Elongated with 333x but a good clean split with 533x. Stars settle to fine points with seeing , ~1 delta mag, ~0.5" separation

STT228

8^m.2

8^m.9

1.7"

170°

2017

Leo

10^h47^m16.93^s / +22°34'32.00"

Robert Zebahl Leipzig (Germany)	70mm (133x)	2021-04-21: Slightly elongated.
Mark McCarthy Fremont (California/USA)	508mm (533x)	With fine focus, split with seeing, ~1 delta mag, ~1" separation. Pretty tough needed 533x to split, elongated at 333x

★★

STT229

7^m.6

7^m.9

0.7"

256°

2020

UMa

10^h48^m02.55^s / +41°06'35.80"

Mark McCarthy

Fremont (California/USA)

317mm (553x)

Just wider than a thin hair split of equal white stars, ~8th mag. 0.63"! in 40 years it will be 0.2"

A2373

8^m.8

0.2"

228°

2011

Leo

10^h52^m02.94^s / +16°05'44.00"

Mark McCarthy

Fremont (California/USA)

508mm (889x)

Just split hairline at best moments, touching disks otherwise, 1 delta mag, very tough. In my notes I put the PA to the NNE, but this is a reversal of what is listed as SE. 100.26-year period, 0.218" now, it will make a barely perceptible arc to the south in the next couple of decades

STF1500

7^m.9

8^m.3

1.2"

301°

2019

Leo

11^h00^m02.02^s / -03°28'16.50"

Mark McCarthy

Fremont (California/USA)

178mm (205x)

Very fine white stars, ~1 delta, ~1.5". Physical with a 680-year period

★

UC2059 & HDS1574 & COU1422

HDS1574

Aa-Ab

7^m.6

11^m.1

0.3"

99°

2019

UMa

11^h01^m45.73^s / +36°40'41.60"

UC2059

7^m.5

10^m.7

46.6"

46°

2015

COU1422

Ba-Bb

11^m.2

11^m.5

0.7"

47°

2016

Mark McCarthy Fremont (California/USA)	317mm (553x)	UC2059 (AB): Pretty well separated, 1.5 delta mag, not remarkable as I hoped given the odd designation.
Mark McCarthy Fremont (California/USA)	762mm (1219x)	COU1422 (Ba-Bb): Cou 1422 is a pair of 11th magnitude stars very close to UC 2059 -- best I could get of Cou 1422 was an elongation with the seeing. Tried 1219x without improving the elongation.

★

A1590

8^m.9

9^m.6

1.5"

328°

2017

UMa

11^h03^m27.91^s / +54°31'33.00"

Mark McCarthy

Fremont (California/USA)

178mm (205x)

Light orange A and blue-green B, >1" separation, half delta mag. Physical with 163-year period, it's not at apastron and won't make significant change for several decades

★★

BU1077, alpha UMa, 50 UMa, Dubhe

2^m.0

5^m.0

0.8"

342°

2017

UMa

11^h03^m43.84^s / +61°45'04.00"

2^m.0

7^m.2

384.5"

206°

2020

Christopher Hay Seeheim (Germany)	7x45	AC: AC: Very wide apart but still feel as if belonging together. A golden-yellow, C seems blue, a very attractive pair. A, B and C are a physical triple system at a distance to us of 123 light years. This is incidentally almost exactly the same distance to us as SMA75 AB, a further wide binocular pair in UMa.
René Merting Drachhausen (Germany)	18x70	AC: Dubhe oder Alpha Ursae Majoris - hm, naja - C zeigt sich im Süden in Riesenabstand zum intensivgelbem A - Komponente C wirkt dagegen wie eine graue Maus und der Helligkeitsunterschied ist so enorm, dass er nicht abschätzbar ist
Christopher Hay Seeheim (Germany)	36mm (8x)	A wide pair but still appearing visually to belong together. Component A is a creamy gold-white. Component C is pale blue, but the colour impression fades after looking for a while. In parallel observation with 3-inch at 32x and 7-inch at 67x I see no particular colour of C, an interesting difference to observation with one-and-a-half-inch. I take a look with 7x42 binoculars and the blue impression is there again, as always with binoculars of all kinds.
Robert Zebahl Leipzig (Germany)	70mm (22x)	AC: 2020-04-07: Very wide, uneven & inconspicuous pair. A appeared white-yellowish, for C I could not detect any color.
Uwe Pilz Leipzig (Germany)	120mm (120x)
Robert Zebahl Leipzig (Germany)	152mm (43x)	AC: 2022-04-12: Very wide and uneven pair. Component A shines in a bright, brilliant orange, companion C looks rather white.
Robert Zebahl Leipzig (Germany)	152mm (200x)	AB: 2022-04-12: At magnifications between 200x and 400x, there was nothing even close to a double star to be seen. The air was simply too turbulent.

★★

HO378

8^m.2

9^m.1

1.1"

234°

2020

UMa

11^h04^m57.29^s / +38°24'38.20"

Mark McCarthy

Fremont (California/USA)

317mm (553x)

In a pretty cluster in the finder (~ 12 stars loose and poor, wide magnitude range, triangle shape). Pair is a fine split 1 delta mag 1", ice blue A and slightly yellow B.

STF1510

7^m.7

9^m.0

5.6"

328°

2020

UMa

11^h08^m00.06^s / +52°49'17.90"

René Merting Drachhausen (Germany)	100mm (64x)	bei 32x wirkt der Stern leicht länglich - bei 64x dann gelingt die Trennung - Komponente B hängt nordwestlich über A und ist mehr als eine Größenklasse schwächer - ein schönes enges Paar bei dieser Vergrößerung - B wirkt trotz des Größenunterschiedes nicht so schmutzig grau, wie es sonst immer ist
Mark McCarthy Fremont (California/USA)	178mm (205x)	>1 delta mag, wide pair. Physical with a 3156.3519-year period

★

STF1517 & BU1431

STF1517

7^m.5

8^m.0

0.7"

313°

2018

Leo

11^h13^m40.99^s / +20°07'43.30"

BU1431

AB-C

7^m.5

10^m.8

246.1"

97°

2015

Sarah Gebauer Germany	100mm (200x)	STF1517 (AB): die Komponenten AB und C lassen sich natürlich problemlos bei geringer Vergrößerung trennen, für A und B reichen auch 200x nicht aus (Beobachtungsversuch erfolgte ohne vorherige Recherche, denn 0,7'' schafft mein Refraktor nicht)
Robert Zebahl Leipzig (Germany)	102mm (187x)	STF1517 (AB): 2020-03-28: At 187x the double star immediately appears elongated, but without notching. On closer observation, the slight difference in brightness could be detected. Not better at higher magnifications. Observation at quite good seeing (4/5).
Uwe Pilz Leipzig (Germany)	105mm (200x)	STF1517 (AB): länglich
Robert Zebahl Leipzig (Germany)	152mm (225x)	STF1517 (AB): 2020-03-27: Clearly elongated. In some moments the double star appeared notched with a small difference in brightness. Observation at moderate seeing (3/5).
Mark McCarthy Fremont (California/USA)	317mm (340x)	STF1517 (AB): Very tight, hair split small orange stars of equal magnitude. Wow!
Mark McCarthy Fremont (California/USA)	508mm (533x)	STF1517 (AB): Touching disks with 333x, clean slit with 533x, ~0.5" separation, Yellow-orange stars, near equal

STF1516 & STT539 & HDS1603

STF1516

7^m.8

8^m.2

67.6"

103°

2017

Dra

11^h15^m11.91^s / +73°28'30.70"

STT539

7^m.8

11^m.3

6.5"

329°

2017

STT539

8^m.2

11^m.3

72.2"

287°

2015

HDS1603

8^m.2

10^m.0

0.1"

115°

1991

Christopher Hay

Seeheim (Germany)

15x45

STF1516 (AB): Handheld binoculars with internal stabilisation. Well separated. Quite evenly matched, visually strong pair. Western component slightly brighter and warmer.

★★

STF1523, xi UMa, 53 UMa, Alula Australis

4^m.3

4^m.8

2.3"

152°

2020

UMa

11^h18^m10.90^s / +31°31'45.00"

Robert Zebahl Leipzig (Germany)	55mm (83x)	2019-02-09: Already seen as '8' at 83x. At 125x the overlapping of both Airy disks was visible, but also a slight difference in brightness.
Robert Zebahl Leipzig (Germany)	70mm (100x)	2018-02-18: Very close together with similar brightness. At first glance seen as an '8', looking closer I partly split both components. Similar view also at 128x.
Robert Zebahl Leipzig (Germany)	70mm (133x)	2020-03-15: Splendid sight! Beautifully separated with almost touching diffraction disks. The rather small difference in brightness was well visible. The diffraction rings of both components coalesced.
Mark McCarthy Fremont (California/USA)	80mm (150x)	Alula australis. Slight magnitude difference, hairline split, light yellow A and darker yellow B.
Robert Zebahl Leipzig (Germany)	102mm (160x)	2020-03-16: Awesome! Bright with lovely, subtle diffraction rings. The distance between both components is a smaller than the diameter of the diffraction disk of the fainter component.
Uwe Pilz Leipzig (Germany)	105mm (288x)	Gemessen: 162°
Robert Zebahl Leipzig (Germany)	120mm (168x)	2018-02-14: Well split with slight difference in brightness.
Robert Zebahl Leipzig (Germany)	152mm (129x)	2019-02-06: Well split with visible difference in brightness. The colors of both components appeared equal.
Mark McCarthy Fremont (California/USA)	508mm (333x)	Alula Australis. Short period. Pretty orange-yellow stars, ~half delta mag, ~2" separation

STF1527

7^m.0

8^m.0

0.5"

301°

2020

Leo

11^h18^m59.91^s / +14°16'06.90"

Mark McCarthy

Fremont (California/USA)

203mm (333x)

At 205x I know something is up with this star. At 333x it is overlapping disks and notched. At 533x it is still only notched but a bit larger and hazier

STF1534

8^m.1

11^m.1

5.1"

314°

2019

Leo

11^h21^m49.34^s / +18°11'24.00"

Mark McCarthy

Fremont (California/USA)

203mm (333x)

Orange-yellow A, very faint B brightens with averted vision, but can hold direct. Wide, ~3 delta mag

★

STF1536, iota Leo, 78 Leo

4^m.1

6^m.7

2.2"

93°

2019

Leo

11^h23^m55.37^s / +10°31'46.90"

AB-C

4^m.1

11^m.1

332.1"

346°

2015

Robert Zebahl Leipzig (Germany)	70mm (133x)	AB: 2020-03-28: The companion was well visible as brightening on the diffraction ring of the primary component. Sketch see observation with my 102mm refractor.
Sarah Gebauer Germany	100mm (200x)	AB: selbst bei 200x nur manchmal getrennt, eher schwierig mit Amiciprisma
Robert Zebahl Leipzig (Germany)	102mm (125x)	AB: 2020-03-28: At 125x clearly separated. A very beautiful sight! The companion was visible as almost round brightening close to the first diffraction ring of the primary component. The diffraction ring itself appeared very fine. At 224x also a very nice sight with a clear diffraction ring and the companion, which now appeared roundish.
Mark McCarthy Fremont (California/USA)	317mm (340x)	AB: Quite close, very bright yellow white A and brownish B, split in A's diffraction ring
Mark McCarthy Fremont (California/USA)	508mm (333x)	AB: Iota Leo. Light orange A and a richer orange B, ~2 delta mag, ~2" separation

★★

STF1540, 83 Leo

6^m.5

7^m.5

28.6"

146°

2019

Leo

11^h26^m45.32^s / +03°00'47.20"

Stefan Loibl Rosenheim (Germany)	10x50	clearly split, little difference in magnitude
Christopher Hay Seeheim (Germany)	10x56	On tripod. Neat split. Attractive 6.3° FOV with a sprinkling of several 5- to 7-mag stars to the south. Tau Leo widely split directly to southeast. In 15x60 on tripod well split, component A slightly orange, forms a fine double-double with Tau Leo. 83 Leo is a physical double at a distance to us of only 58 light years.
Robert Zebahl Leipzig (Germany)	16x70	2021-03-02: Splendid sight together with the double star tau Leo as well as 82 Leo. Beautiful star field. 83 Leo very nicely separated with moderate difference in brightness. Yellowish orange & slightly orange.
René Merting Drachhausen (Germany)	18x70	ein ordentlich getrenntes und dennoch schön eng stehendes Pärchen - Komponente A ist leicht gelblich, Komponente B im SO ist eine dreiviertel Magnitude schwächer und grauweiß
Robert Zebahl Leipzig (Germany)	55mm (16x)	Wonderful double with slight color contrast in a very nice field. Together with tau Leo stunning view. Slightly unequal. A appeared white-yellowish, B rather grey-bluish.
Mark McCarthy Fremont (California/USA)	80mm (13x)	Finder split, in same field as Tau.
Mark McCarthy Fremont (California/USA)	178mm (205x)	Light orange-yellow A and light blue B, >1 delta mag, very wide. Physical with 32,000-year period. Running this through the Plot Tool with EDR3 data, it confirms it is physical, only 18 parsecs / 58 light years away (which is why it has such a high proper motion) and 520 AU separation
Mark McCarthy Fremont (California/USA)	317mm (340x)	Yellow A and reddish B wide separation.
René Merting Drachhausen (Germany)	320mm (72x)	bei 72x steht das Paar zwar weit auseinander, es wirkt aber trotzdem gut zusammengehörend - Komponente B im SO ist eine dreiviertel Magnitude schwächer

STT234

7^m.5

8^m.1

0.4"

182°

2019

UMa

11^h30^m49.91^s / +41°17'12.70"

Mark McCarthy

Fremont (California/USA)

508mm (1067x)

Surprisingly tough. Had indications of elongation at powers starting from 533x, but needed 1067x to get the clear bump, but even then it wasn't cleanly split

★

STF1547, 88 Leo

6^m.3

9^m.1

15.7"

330°

2020

Leo

11^h31^m44.94^s / +14°21'52.20"

Robert Zebahl Leipzig (Germany)	55mm (42x)	Well split with moderate distance. Primary component appeared white-yellowish. Pretty unequal pair.
René Merting Drachhausen (Germany)	100mm (32x)	bei 32x erscheint Komponente B nordwestlich von A etwas mehr als knapp getrennt ganz schwach, bestimmt 3 Größenklassen Helligkeitsunterschied - Komponente A warmweiß, B ist grau
Sarah Gebauer Germany	100mm (45x)	fein, aber gut getrennt, die südliche Komponente ist deutlich heller, die nordwestliche zeigt sich als ganz schwacher Punkt
Uwe Pilz Leipzig (Germany)	105mm (88x)	gelb und violett
Mark McCarthy Fremont (California/USA)	178mm (205x)	Very light yellow and 2 delta, very wide B. Physical, with a 3453-year period, it is also close-by at 23.33 pc
Gerd Kohler Langenzenn (Germany)	254mm (76x)	Der Doppelstern ist getrennt.Bläulich-weiß - orange-leicht rötlich. Etwas schwächerer Begleiter.
Mark McCarthy Fremont (California/USA)	317mm (340x)	88 Leonis: A favorite! Yellow and blue pair, wide
René Merting Drachhausen (Germany)	320mm (45x)	bei 45x ein schönes enges Sternpaar, ordentlich getrennt - Komponente A strahlt hellgelb, B ist deutlich schwächer und empfiehlt sich mit einem Kupferton - ein schöner Farbkontrast

★★

STT235

5^m.7

7^m.5

0.9"

43°

2017

UMa

11^h32^m20.76^s / +61°04'57.90"

Mark McCarthy Fremont (California/USA)	317mm (553x)	Nice! Yellow and orange, 1.5 delta mag, split when seeing shows perfect disks. The stars both show albedo effects, look like suns / globes with shadowing.
Mark McCarthy Fremont (California/USA)	508mm (533x)	Short period. Pretty yellow A, orange B, ~1" ~2 delta mag

★

STF1555 & HJ503

STF1555

6^m.4

6^m.8

0.7"

151°

2019

Leo

11^h36^m17.94^s / +27°46'52.70"

HJ503

AB-C

5^m.8

11^m.2

22.5"

156°

2016

Frederik Wanink Itterbeck (Germany)	254mm (640x)	STF1555 (AB): blickweise gerade eben trennbar
Mark McCarthy Fremont (California/USA)	317mm (443x)	STF1555 (AB): Nice! AB tight hair-split white pair, with fainter & wide separated AB-C in a row to the east.
Mark McCarthy Fremont (California/USA)	317mm (443x)	HJ503 (AB-C): Nice! STF 1555AB tight hair-split white pair, with fainter & wide separated C in a row to the east.
Mark McCarthy Fremont (California/USA)	508mm (553x)	STF1555 (AB): Hairline split at 333x, clear split with 533x, very close ~0.5", bright. Part of plus one

STF1553

7^m.7

8^m.2

6.2"

165°

2019

UMa

11^h36^m35.69^s / +56°08'07.30"

René Merting Drachhausen (Germany)	18x70	der Doppelstern zeigt sich länglich, aber nicht getrennt - die Einschnürung ist auch nur zu erahnen, aber man sieht auf jeden Fall, dass dort kein Einzelstern steht
Robert Zebahl Leipzig (Germany)	70mm (31x)	2020-04-19: At 22x medium bright double star with apparently similar bright components. At first sight visible as '8', on closer look separated. At 31x very fine split of the components with small difference in brightness. The two components appeared yellowish and slightly orange.
Mark McCarthy Fremont (California/USA)	178mm (205x)	White, pretty wide, 1 delta mag, typical Struve. Physical with a 1996-year period, slowly approaching apastron
René Merting Drachhausen (Germany)	320mm (45x)	bei 45x sehe ich zwei fast gleich helle Sterne ganz eng beieinander stehen, da passt sprichwörtlich kein Blatt Papier dazwischen - bei 72x Helligkeitsunterschied eine knappe halbe Magnitude - ein ganz feiner Farbunterschied, Komponente A leicht weißgelblich, B im Osten wirkt ein bisschen grau

STF1561

6^m.5

8^m.2

8.9"

246°

2019

UMa

11^h38^m44.90^s / +45°06'30.30"

6^m.5

9^m.5

176.8"

90°

2015

6^m.5

7^m.6

718.2"

76°

2015

6^m.5

12^m.1

60.7"

338°

2015

Christopher Hay Seeheim (Germany)	7x45	AD: So far apart they don't really feel as if they belong together, but what the heck. A rather interesting 5° long chain of 6-to-8-mag stars runs through FOV, starting in south with STF 1542.
Robert Zebahl Leipzig (Germany)	70mm (31x)	AB: 2020-04-19: At 22x separated, but relatively tight together with significant difference in brightness. The pair stands close to 2 medium bright stars. Both components appear white. At 31x beautiful sight, the color of the components looks slightly different: white-yellowish with darker ( slightly orange?) companion.
Robert Zebahl Leipzig (Germany)	70mm (44x)	AB: 2020-04-07: At 22x separated. The fainter companion is still very close to the primary component. At 44x beautiful sight with a clear difference in brightness. A: slightly yellowish, B: pale bluish.

★

BU603

6^m.0

8^m.5

1.0"

329°

2019

Leo

11^h48^m38.71^s / +14°17'03.20"

Mark McCarthy Fremont (California/USA)	80mm (150x)	Elongated but not split. 129-year period
Uwe Pilz Leipzig (Germany)	105mm (200x)	sehr schwierig
Uwe Pilz Leipzig (Germany)	105mm (288x)	nicht getrennt
Mark McCarthy Fremont (California/USA)	203mm (533x)	Suspected at 205x and 333x but needed higher magnification to see it. B is a very small point, with seeing, in the first diffraction ring. ~1" and ~3 delta mag

STT241

6^m.8

8^m.7

1.8"

147°

2017

UMa

11^h56^m17.24^s / +35°26'53.30"

Robert Zebahl

Leipzig (Germany)

120mm (200x)

2021-04-04: Well separated with noticeable difference in brightness.

STF1606

7^m.4

7^m.9

0.7"

143°

2019

CVn

12^h10^m47.34^s / +39°53'29.50"

Robert Zebahl

Leipzig (Germany)

120mm (200x)

2021-04-04: The double star appeared slightly elongated.

STF1608

8^m.1

8^m.3

13.6"

221°

2021

UMa

12^h11^m27.76^s / +53°25'17.50"

René Merting Drachhausen (Germany)	18x70	wie gemacht für 18x - ein Paar gleich heller Sterne, minimalst getrennt - B scheint im Südwesten zu stehen, der Stern ist nur minimal schwächer
Robert Zebahl Leipzig (Germany)	70mm (22x)	2020-04-19: Easy to find, medium bright. At 22x quite conspicuous with rather small difference in brightness. A difference in color is clearly visible: slightly orange, white-bluish. At 31x nice color contrast with a little more intensive colors: light orange & light blue.
Mark McCarthy Fremont (California/USA)	178mm (205x)	Yellow-white stars, near equal, wide. Physical with a 2236-year period, it is nearing apastron now. It's also variable star MZ UMa, which as best as I can find has a 0.02 magnitude change over a 7.96 day period
René Merting Drachhausen (Germany)	320mm (72x)	bei 72x ein schönes helles Pärchen, beide Komponenten sind gleich hell und zahncremeweiß

STF1639

6^m.7

7^m.8

1.9"

324°

2019

Com

12^h24^m26.81^s / +25°34'56.70"

6^m.7

11^m.4

91.4"

159°

2015

Robert Zebahl Leipzig (Germany)	70mm (133x)	AB: 2020-04-04: The double star is clearly elongated, with the fainter companion attached to the primary component.
Mark McCarthy Fremont (California/USA)	203mm (205x)	AB: White and slightly blue pair, close, around 3"
Mark McCarthy Fremont (California/USA)	317mm (443x)	AB: Close but well split, 1.5 delta mag, ~2.5"
Mark McCarthy Fremont (California/USA)	508mm (333x)	AB: Pretty yellow stars, ~2" separation, ~2 delta mag

STF1643

9^m.0

9^m.4

2.8"

3°

2020

Com

12^h27^m13.72^s / +27°01'29.60"

Mark McCarthy Fremont (California/USA)	317mm (553x)	Equal orange pair, ~3", PA to north.
Mark McCarthy Fremont (California/USA)	508mm (333x)	Yellow-white stars, ~3" separation, ~2 delta mag

STF1645

7^m.5

8^m.1

9.8"

156°

2017

CVn

12^h28^m04.45^s / +44°47'39.50"

Mark McCarthy Fremont (California/USA)	178mm (205x)	Slight delta, wide, pretty light yellow-white stars. WDS lists as physical, and I agree
Gerd Kohler Langenzenn (Germany)	254mm (76x)	Der Doppelstern ist getrennt. Bläulich-weiß - bläulich-weiß. Gleiche Helligkeit.
Mark McCarthy Fremont (California/USA)	317mm (277x)	Wide, bright yellowish-white pair, ~1 delta mag

Berthold Fuchs

Wiesbaden (Germany)

130mm

easy DS

../projects/double-stars/berthold-fuchs/photographs/STF%201645.png

STT251

8^m.3

9^m.3

0.7"

55°

2018

CVn

12^h29^m07.72^s / +31°23'25.40"

Mark McCarthy Fremont (California/USA)	317mm (553x)	Decidedly not round disk -- there's also a brightening in the diffraction. Marginal.
Mark McCarthy Fremont (California/USA)	508mm (667x)	Best seen at 667x, but could also see at 533x and 445x. Split, much fainter B about 1.5 delta mag, light orange A and blue B. 540.56-year period, it will reach apastron in 100 years but makes a very close periastron in 400 years

★★

WRH12, 23 Com

5^m.0

6^m.9

0.4"

8°

2020

Com

12^h34^m51.12^s / +22°37'45.10"

Mark McCarthy

Fremont (California/USA)

508mm (1067x)

23 Com. I get a definite snowman and can tell the larger from the smaller star, pointed in a certain direction in relation to a faint field star. Short Period double

STF1663

8^m.0

9^m.2

0.5"

65°

2017

Com

12^h37^m10.81^s / +21°11'52.50"

Mark McCarthy

Fremont (California/USA)

203mm (333x)

Hairline split, ~1 delta mag, tough. Light yellow-orange A

★★★

STF1670, gamma Vir, 29 Vir, Porrima

3^m.5

2.5"

4°

2020

Vir

12^h41^m39.60^s / -01°26'57.90"

Christopher Hay Seeheim (Germany)	15x60	28 February 2021 at 3" separation: Very slight elongation. PA estimated at 5° (thus only 9° off, which seems fairly precise to me considering the low power of 15x and the minimal elongation, both of which make PA estimation difficult). Intentionally flashed the eyes on the almost full Moon directly prior to observation in order to enhance acuity. Compared the sight of Porrima repeatedly with that of similarly bright Epsilon Vir (Vindemiatrix) to check whether the elongation is perhaps an artefact of the bincolulars or of my eyes, but no elongation seen there.
Robert Zebahl Leipzig (Germany)	16x70	2021-05-23: Not even close to appear as a double star. The components are just too bright, the separation too small.
Robert Zebahl Leipzig (Germany)	55mm (56x)	2019-05-18: At 38x slightly elongated. At 56x touching diffraction disks. At 71x clearly separated with very small gap.
Robert Zebahl Leipzig (Germany)	70mm (44x)	2021-05-26: At full aperture Porrima appears almost separated at 44x. The two diffraction disks are well visible. At 31x it is difficult to see any elongation at all. At 40mm aperture Porrima can be seen clearly elongated already at 31x, from 67x it appears as an '8'. At only 22x Porrima is not visible as a double star.
Robert Zebahl Leipzig (Germany)	70mm (104x)	2019-05-04: At 47x clearly visible as '8', at 73x split with almost touching diffraction disks. At 104x clearly separated, equally bright and pretty close together. The gap was smaller than the diameter of the diffraction disk.
Mark McCarthy Fremont (California/USA)	80mm (92x)	Porrima. Nice and easy, yellow-white equal stars. 169-year period
Robert Zebahl Leipzig (Germany)	102mm (125x)	2019-05-01: Extremely nice double star! Equally bright and relatively close together. Both components appeared yellowish-white.
Uwe Pilz Leipzig (Germany)	105mm (200x)	weiß-weiß, die nördliche Komponente ist eine Winzigkeit heller
Winfried Kräling Marburg (Germany)	127mm (146x)	21.04.2018: Bei V=100x erscheint dieser orangefarbene Doppelstern bereits als „8“. Bei V=146x ist Porrima voll getrennt.
Sarah Gebauer Germany	150mm (166x)	die 2,8'' entfernten Komponenten A und B konnten haarscharf bei 83x und 166x getrennt werden, beide strahlen gleich hell als ganz dichte Glanzpünktchen; Komponenten E und F wurden gesehen, C und D allerdings nicht; bei 83x waren AB ganz knapp nicht mehr voneinander getrennt
Mark McCarthy Fremont (California/USA)	178mm (205x)	Porrima. Bright near equal, dull white, well split about 4". Physical with a 169-year period, I missed my chance to witness the rapid periastron a few years ago
Mark McCarthy Fremont (California/USA)	317mm (170x)	Porrima. Very pretty yellow-white, near equal, close split at 170x. Star disks improved with apodizing mask.

COU1579

9^m.4

9^m.7

0.2"

135°

2012

CVn

12^h53^m17.33^s / +42°46'16.80"

Mark McCarthy

Fremont (California/USA)

508mm (889x)

Very tough notched elongation and instants of splits, I had difficulty sketching it and estimated PA west of north or along that line. Very small scale. Actual PA is SSE, so I had the alignment correct. It will be at periastron next year, and get to easy split by 2029 at around 0.231", at the opposite quadrant

STF1687, 35 Com

5^m.2

7^m.1

1.2"

203°

2020

Com

12^h53^m17.77^s / +21°14'42.10"

5^m.2

9^m.8

28.5"

127°

2016

Mark McCarthy Fremont (California/USA)	203mm (205x)	AC: Rich light yellow and much fainter wide blue B. Near M64. [Need to re-observe. I saw the wide AC, but not the AB which is 5.15/7.08 1.2"
Mark McCarthy Fremont (California/USA)	317mm (205x)	AC: Rich light yellow and much fainter wide blue B. Near M64. (Need to re-observe. I saw the wide AC, but not the AB which is 5.15/7.08 1.2")
Mark McCarthy Fremont (California/USA)	317mm (443x)	AC: Orange and blue, 3 delta mag, very wide separation to the east. Did not notice AB
Mark McCarthy Fremont (California/USA)	317mm (553x)	AB: 35 Com: Bright orange & fainter B, showpiece, ~1.5"
Mark McCarthy Fremont (California/USA)	508mm (533x)	AB: 35 Com. Can see the 7th magnitude B at 333x, but it's easier to resolve with 533x. Part of plus one. Bright orange A and deeper orange B

STT256

7^m.3

7^m.6

1.1"

101°

2017

Vir

12^h56^m26.59^s / -00°57'16.60"

Mark McCarthy

Fremont (California/USA)

317mm (553x)

Wide separation equal brightness white stars

78 UMa, BU1082

5^m.0

7^m.9

0.7"

141°

2019

UMa

13^h00^m43.59^s / +56°21'58.80"

Uwe Pilz

Leipzig (Germany)

105mm (260x)

nicht getrennt

STT261

7^m.4

7^m.6

2.5"

337°

2020

CVn

13^h12^m02.02^s / +32°05'07.90"

Robert Zebahl Leipzig (Germany)	70mm (57x)	2020-04-20: At 44x immediately visible as figure '8', even separable on closer look. The components appeared similarly bright. Overall rather dim. At 57x clearly split, but still very close together with a small difference in brightness.
Mark McCarthy Fremont (California/USA)	203mm (205x)	Light yellow-white equal pair, ~1.5"

RST3829 & SHJ162

RST3829

Aa-Ab

7^m.3

9^m.1

0.5"

166°

2018

Vir

13^h14^m55.72^s / -11°22'09.90"

SHJ162

7^m.1

8^m.2

114.2"

45°

2020

SHJ162

8^m.2

13^m.3

66.2"

136°

2015

René Merting Drachhausen (Germany)	100mm (32x)	SHJ162 (AB): bei 32x weit auseinander stehend - ein eigentümlicher Farbkontrast, A strahlt weiß, B kupfern
Mark McCarthy Fremont (California/USA)	317mm (340x)	SHJ162 (AB): a widely separated yellow A and orange B, 1 magnitude difference.

★

BU800

6^m.7

9^m.5

7.7"

104°

2020

Com

13^h16^m51.05^s / +17°01'01.90"

Christopher Hay Seeheim (Germany)	125mm (36x)	AB, March 2019: Clearly split in good moments, but secondary popping in and out of view in instable seeing. A physical double only 36 light years distant to us.
Mark McCarthy Fremont (California/USA)	203mm (333x)	Nice pair, A is a light but rich yellow, B is blue-white. Wide, ~2 delta mag
Mark McCarthy Fremont (California/USA)	317mm (553x)	Not difficult, orange-yellow A with bluish B, 3 delta mag. pretty wide to east.

★★

HU644

9^m.1

9^m.9

0.1"

354°

2019

CVn

13^h19^m45.58^s / +47°46'41.10"

Uwe Pilz Leipzig (Germany)	120mm (250x)
Mark McCarthy Fremont (California/USA)	317mm (443x)	Orange-red pair, near equal mag, split with seeing at 443x
Mark McCarthy Fremont (California/USA)	508mm (533x)	Quite perfect star images, light orange stars, nearly 2 delta mag, well separated, PA northwest. Grade 2, physical, 48.776-year period. It has a slightly out of round orbit from our perspective, near it's periastron now and will widen to an easy 1.584" by 2030

STF1734

6^m.8

7^m.3

1.1"

173°

2017

Vir

13^h20^m41.57^s / +02°56'31.90"

Robert Zebahl Leipzig (Germany)	70mm (104x)	Double star appeared slightly elongated without noticeable notching.
Mark McCarthy Fremont (California/USA)	203mm (333x)	Blue-white A, light orange B, half delta mag, close ~1.5". Nice!

HO260

9^m.6

9^m.9

1.7"

89°

2019

CVn

13^h23^m32.82^s / +29°14'15.00"

Mark McCarthy

Fremont (California/USA)

203mm (205x)

Close pair, nicely split ~2", ~1 delta mag, light orange stars

A1609

9^m.5

8^m.8

0.3"

87°

2020

CVn

13^h25^m48.12^s / +44°29'38.30"

Mark McCarthy

Fremont (California/USA)

508mm (889x)

Notched elongation with the fainter end PA just south of east, very difficult, with seeing only. 44.24-year period, it is nearing periastron and won't appreciably widen, at the opposite PA, until the mid 2030s

STT266

8^m.0

8^m.4

1.9"

355°

2020

Com

13^h28^m26.68^s / +15°42'30.50"

Mark McCarthy Fremont (California/USA)	203mm (333x)	~0.5 delta mag, ~2 separation, nice looking pair
Mark McCarthy Fremont (California/USA)	317mm (553x)	Close 2" near equal white. Period of 1954.11 years. Near its closest separation now (May 2017), will be ~4" by the year 2822.

STF1752

8^m.2

9^m.9

1.0"

107°

2017

UMa

13^h28^m49.82^s / +59°55'41.70"

Mark McCarthy

Fremont (California/USA)

317mm (553x)

Orange star perhaps a little elongated, tough.

VYS6, VW Com

11^m.4

11^m.3

2.6"

55°

2018

Com

13^h32^m44.59^s / +16°48'39.00"

Mark McCarthy

Fremont (California/USA)

317mm (553x)

VW Com. Seen best with averted vision and when seeing stills. Close but pretty well split, ~2-3". Extremely faint reddish pair, PA NE.

STT269

7^m.3

8^m.1

0.3"

222°

2019

CVn

13^h32^m51.02^s / +34°54'25.80"

Mark McCarthy

Fremont (California/USA)

508mm (1067x)

Strong notch, good star images, not quite split. I saw it as a rod at 205x, and the notch increased in strength with each magnification step up. PA to SW. Physical with grade 2 orbit and 53.2-year period (having made nearly one revolution in my lifetime so far!), it is 0.297" now and is coming off apastron, it will rapidly close to undetectability by the late 2030s

A1095

9^m.0

9^m.3

0.3"

288°

2016

CVn

13^h33^m33.77^s / +29°44'16.90"

Mark McCarthy

Fremont (California/USA)

508mm (889x)

Hairline split, >1 delta mag. 187-year period, it will make a slight movement to the north in my lifetime but will be closer to periastron

STF1757

7^m.8

8^m.8

1.6"

144°

2019

Vir

13^h34^m16.38^s / -00°18'49.80"

Uwe Pilz Leipzig (Germany)	105mm (200x)	schwierig
Mark McCarthy Fremont (California/USA)	203mm (205x)	Close, ~2", a dull orange, ~1.5 delta mag.
Mark McCarthy Fremont (California/USA)	317mm (553x)	Orange-yellow, half a delta mag, pretty, ~1.5"

BU932, y Vir

6^m.3

7^m.3

0.4"

67°

2019

Vir

13^h34^m40.48^s / -13°12'51.50"

Mark McCarthy

Fremont (California/USA)

317mm (170x)

Out of round with apodizing mask

★

25 CVn

STF1768

5^m.0

7^m.0

1.6"

95°

2020

CVn

13^h37^m27.70^s / +36°17'41.40"

STF1768

5^m.0

11^m.6

214.3"

321°

2015

KZA73

5^m.0

13^m.0

335.6"

92°

2015

KZA73

5^m.0

12^m.7

371.6"

139°

2020

KZA73

5^m.0

9^m.4

437.3"

118°

2015

Robert Zebahl Leipzig (Germany)	60mm (160x)	AB: 2020-03-16: 102/1122mm ED refractor stopped down to 60mm. The diffraction ring of the primary component is virtually invisible. The companion appears only in few moments as an extremely faint, elongated brightening in the diffraction ring. Very difficult. Telescope should be in very good optical condition!
Robert Zebahl Leipzig (Germany)	70mm (160x)	AB: 2020-03-16: 102/1122mm ED refractor stopped down to 70mm. Companion only visible as a subtle, elongated, not permanently visible brightening. The diffraction ring of the primary component is only visible occasionally. Difficult. Telescope should be in good optical condition!
Robert Zebahl Leipzig (Germany)	80mm (160x)	AB: 2020-03-16: 102/1122mm ED refractor stopped down to 80mm. Companion permanently visible as elongated brightening in the diffraction ring. But the diffraction ring itself appears rather faint. Moderately difficult.
Robert Zebahl Leipzig (Germany)	90mm (160x)	AB: 2020-03-16: 102/1122mm ED refractor stopped down to 90mm. Companion quite clearly recognizable as elongated brightening in diffraction ring. Relatively simple.
Robert Zebahl Leipzig (Germany)	102mm (160x)	AB: 2020-03-16: The faint companion is immediately recognizable as a distinct, slightly elongated brightening in the diffraction ring. Easy.
Robert Zebahl Leipzig (Germany)	152mm (150x)	AB: 2020-03-19: At 150x the clearly fainter companion is visible as a roundish brightening. Due to the chromatic aberration of the achromat (152mm f/5.9) the companion is almost outshined. At 180x the companion is then well, at 225x and 300x very well visible as a tiny separated star.
Mark McCarthy Fremont (California/USA)	203mm (205x)	AB: Very tight pair, a little more than hairline split, ~2 delta mag.
Mark McCarthy Fremont (California/USA)	203mm (205x)	AB: Very tight pair, a little more than hairline split, ~2 delta mag. 8" 333x: white and dull blue, ~1", Nice!
Frederik Wanink Itterbeck (Germany)	254mm (640x)	AB: schwierig wegen Helligkeitsunterschied
Mark McCarthy Fremont (California/USA)	317mm (277x)	AB: Very pretty pale yellow and orange, 2-3 delta mag, ~2"

STF1769

7^m.9

10^m.4

1.6"

45°

2015

CVn

13^h38^m01.95^s / +39°10'41.00"

7^m.9

9^m.3

56.2"

259°

2015

7^m.9

13^m.0

149.4"

187°

2015

9^m.3

13^m.0

141.8"

165°

2015

René Merting Drachhausen (Germany)	100mm (32x)	AC: bei 32x ein weit auseinander stehendes Pärchen - B im Westen ist eine Größenklasse schwächer als die weiße Komponente A und wirkt gegen A richtiggehend blaugrau
Mark McCarthy Fremont (California/USA)	203mm (333x)	AC: Wide separated blue stars, half delta mag. 2+1 system? 1 delta mag fainter star quite more widely separated. (Sextuple system. I missed the 1.6" AB, need to re-observe. Saw the AC pair only -- the fainter star noticed may be part of the system.)

BU612

6^m.3

6^m.5

0.1"

51°

2020

Boo

13^h39^m34.68^s / +10°44'46.70"

Mark McCarthy

Fremont (California/USA)

508mm (1067x)

Lightest orange, notched elongation to snowman at best moments. Burnham discovered in 1878 with the Dearborn 18.5-inch, and in 1899 wrote: "It was very soon apparent from the measures that this was a binary system in rapid motion. In the twenty years covered by the measures, the companion has passed over an arc of 175-degrees. Glasenappâ€¦has computed an orbit from which he finds a period of 30.00 years....This represents the observations as well as could be desired, but evidently the arc was too short for any very accurate determination, and even now widely differing apparent orbits will satisfy the observed positions equally. It is probably that the measures of the next ten years will furnish sufficient data for an orbit which shall substantially correct." In the period since, there have been many measures, and a grade 1 Definitive orbit is established. WDS lists it as physical with a 22.46-year period, currently at 0.1 but will widen to 0.3" by 2030 -- I can hope for a clean split by then

STF1781, HT Vir

7^m.9

8^m.1

1.1"

198°

2020

Vir

13^h46^m06.75^s / +05°06'56.10"

Mark McCarthy

Fremont (California/USA)

203mm (333x)

White A and slightly yellow B, ~2", half delta mag

STF1785

7^m.4

8^m.2

2.6"

191°

2020

Boo

13^h49^m04.00^s / +26°58'47.70"

Mark McCarthy Fremont (California/USA)	203mm (333x)	Slightly orange-tinged white stars, near equal, well separated
Karsten Kopp Köln (Germany)	600mm (180x)	Im CLT bei 180 x Vergrößerung gut zu trennen. Leichter Helligkeitsunterschied und beider Sterne erscheinen gelborange.

STF1789

8^m.6

9^m.0

6.7"

328°

2021

CVn

13^h54^m05.19^s / +32°49'35.20"

Robert Zebahl Leipzig (Germany)	70mm (31x)	2020-04-20: At 22x clearly visible as figure '8' and almost separated. At 31x fine separation of the still close pair. A slight difference in brightness and color is visible: white-yellowish, yellowish-orange.
Mark McCarthy Fremont (California/USA)	317mm (277x)	Pretty equal magnitude white, well separated.

Berthold Fuchs

Wiesbaden (Germany)

130mm

difficult DS

../projects/double-stars/berthold-fuchs/photographs/STF%201789.png

★

STF1788

6^m.7

7^m.3

3.7"

101°

2019

Vir

13^h54^m58.20^s / -08°03'31.90"

Robert Zebahl Leipzig (Germany)	70mm (47x)	Very nice view! Pretty tight together with a moderate difference in brightness.
René Merting Drachhausen (Germany)	100mm (64x)	bei 107x zeigt sich ein schönes, knapp getrenntes Pärchen - B im Osten ist nur knapp schwächer als A - Komponente A ist weiß, B ist grau, wirkt aber auch leicht gelb gefärbt - zurück auf 64x kann ich die beiden Sterne auch schon knapp getrennt erkennen
Mark McCarthy Fremont (California/USA)	317mm (340x)	bright pair of near equal magnitude, both yellow-while color.

A1097 & STF1800

A1097

9^m.1

8^m.2

0.4"

259°

2016

UMa

14^h02^m00.60^s / +57°13'28.60"

STF1800

AB-C

7^m.8

10^m.4

28.4"

20°

2015

Mark McCarthy Fremont (California/USA)	317mm (553x)	A1097 (AB): Hair-split at best moments, half delta mag, <0.8". A fainter star likely in the system about 30" distant -- this is STF 1800 AB-C.
Mark McCarthy Fremont (California/USA)	317mm (553x)	STF1800 (AB-C): Faint star ~30" from A1097

STT277 & STF1812

STT277

8^m.7

8^m.6

0.2"

64°

2009

Boo

14^h12^m26.68^s / +28°43'02.30"

STF1812

AB-C

7^m.9

9^m.4

14.1"

108°

2016

STF1812

AB-D

7^m.9

12^m.1

72.6"

153°

2015

René Merting Drachhausen (Germany)	18x70	STF1812 (AB-C): mit etwas Geduld zeigt sich C sehr schwach und knapp abgesetzt östlich von AB - nur mit hoher Konzentration, aber machbar
René Merting Drachhausen (Germany)	100mm (20x)	STF1812 (AB-C): bei 20x ist die C-Komponente östlich knapp getrennt von AB gerade so erkennbar - bei 32x dann schön getrenntes Pärchen, C-Komponente deutlich schwächer, vielleicht 2 mag weniger
Mark McCarthy Fremont (California/USA)	203mm (205x)	STF1812 (AB-C): A 2+1 system with AB-D. Main pair 2.5 delta mag, pretty wide. The third, fainter pair about 4x the other separation.

STF1820

9^m.1

9^m.4

2.8"

123°

2019

UMa

14^h13^m00.76^s / +55°19'31.10"

René Merting

Drachhausen (Germany)

320mm (144x)

bei 72x ist ein Stäbchen mit einer angedeuteten Einschnürung erkennen - bei 144x sind beide Komponenten getrennt voneinander sichtbar - beide sind gleich hell

★

BU224

8^m.9

9^m.3

0.6"

101°

2016

Boo

14^h13^m26.94^s / +12°34'26.20"

Mark McCarthy

Fremont (California/USA)

203mm (333x)

Hairline split with seeing, light yellow-white stars, noticeable mag difference. Snowman when seeing is not stable

★★

STF1821, kappa Boo, 17 Boo, Asellus Tertius

4^m.5

6^m.6

13.8"

235°

2019

Boo

14^h13^m29.00^s / +51°47'23.80"

Christopher Hay Seeheim (Germany)	15x60	On tripod. Fine split. Attractive together with well-split Iota Boo in 3.3° FOV. Iota, Kappa, Theta were called Aselli by Johannes Bayer in the 17th century, meaning The Donkeys. The group is found easily naked-eye under a 5mag sky. Kappa Boo is Asellus Tertius, The Third Donkey. A physical double at a distance to us of 163 light years.
René Merting Drachhausen (Germany)	18x70	Komponente A strahlt so hell, dass B deutlich schwächer ganz knapp im SW von A abgesetzt sichtbar ist - Helligkeitsunterschied schätzungsweise 3 Magnituden (nur 2.09 mag laut Stelle Doppie)
Robert Zebahl Leipzig (Germany)	70mm (22x)	2020-04-24: Clearly separated with significant difference in brightness. The primary component showed a pale yellowish-orange color with a greyish companion. To the southeast there is the double star STFA 26.
Sarah Gebauer Germany	100mm (73x)	sehr schön zusammen mit STFA 26 in einem Gesichtsfeld bei 73x, dabei sehr schön getrennt
Uwe Pilz Leipzig (Germany)	105mm (144x)	weiß-grau, trennbar bei 22x
René Merting Drachhausen (Germany)	320mm (45x)	bei 45x schicker Anblick und schön zusammen im Gesichtsfeld mit sehr ähnlichen Doppelstern STTA 26 - hier aber eine knappere Trennung und B steht im Südwesten von A - ähnlicher Farbkontrast wie beim Nachbardoppelstern, A ist weiß-gelb, B ist blau-grau
Karsten Kopp Köln (Germany)	600mm (180x)	Im CLT leicht zu trennen. Beider Sterne erscheinen weißlich.

★

STF1816

7^m.4

7^m.8

0.4"

100°

2019

Boo

14^h13^m54.63^s / +29°06'19.50"

Uwe Pilz Leipzig (Germany)	105mm (88x)	gelb
Mark McCarthy Fremont (California/USA)	178mm (533x)	Notched elongation, unequal pair, seeing won't support higher magnification. Physical with 1340-year period, it is near periastron now and will remain there the rest of my lifetime
Mark McCarthy Fremont (California/USA)	317mm (553x)	Rod-shaped equal white. July 2017

★★

A1101

9^m.7

10^m.3

0.3"

221°

2020

Boo

14^h15^m50.57^s / +10°17'59.30"

Mark McCarthy

Fremont (California/USA)

508mm (1067x)

I stared for a long time and had brief instants of an elongation or bump, and even a tentative split of a star. Sketched the orientation will check the PA later [I think I have it. My orientation on the sketch is in the correct position as in relation to the AB-C & AB-D pairs.]

★

STF1825

6^m.5

8^m.4

4.2"

154°

2019

Boo

14^h16^m32.84^s / +20°07'18.70"

Mark McCarthy Fremont (California/USA)	80mm (94x)	Very fine split, >2 delta mag, white A and blue B, nice
Mark McCarthy Fremont (California/USA)	203mm (333x)	Cream white A and light blue B, wide ~5", ~2 delta mag
Mark McCarthy Fremont (California/USA)	317mm (277x)	White and orange, 3 delta mag, well split.

STF1834

8^m.1

8^m.3

1.6"

103°

2019

Boo

14^h20^m17.60^s / +48°30'25.10"

Robert Zebahl

Leipzig (Germany)

120mm (150x)

At 108x elongated, at 150x barely split with similarly bright components.

★★

STF1835 & BU1111

STF1835

A-BC

5^m.0

6^m.8

6.4"

197°

2020

Boo

14^h23^m22.74^s / +08°26'47.90"

BU1111

7^m.4

7^m.7

0.3"

25°

2020

René Merting Drachhausen (Germany)	100mm (64x)	STF1835 (A-BC): bei 32x erscheint der Stern leicht unrund, verschmiert - bei 107x präsentiert sich BC gut getrennt im Süden von A - Helligkeitsunterschied eine Größenklasse (1.75 mag laut Stelle Doppie) - bei 64x sind beide Sterne auch getrennt erkennbar, BC strahlt warmweiß
Robert Zebahl Leipzig (Germany)	102mm (62x)	STF1835 (A-BC): At 28x barely split with visible difference in brightness. At 62x easy to separate. The colors seemed similar.
Mark McCarthy Fremont (California/USA)	317mm (277x)	STF1835 (A-BC): In a line of three stars, white and slightly red B. Wide, ~6", 2 delta mag. Did not detect BC 0.3"
Mark McCarthy Fremont (California/USA)	508mm (1067x)	BU1111 (BC): Short period pair, it is a component of STF 1835. I get a nothed near equal elongation with a clear direction in relation to the A star. Very cool
Karsten Kopp Köln (Germany)	600mm (180x)	STF1835 (A-BC): Doppelstern konnte im CLT gut getrennt werden. Helligkeitsunterschied ist merklich, aber nicht extrem. Der hellere erscheint eher weißlich und der kleinere eher bläulich. Der Farbunterschied ist aber minimal.

Berthold Fuchs

Wiesbaden (Germany)

130mm

STF1835 (A-BC): close DS

../projects/double-stars/berthold-fuchs/photographs/STF%201835.jpg

HU1268

9^m.8

9^m.9

0.4"

338°

2019

Boo

14^h29^m32.75^s / +36°12'26.00"

Mark McCarthy

Fremont (California/USA)

203mm (533x)

Notched elongation, white, near equal

STF1858

8^m.1

9^m.0

3.1"

38°

2020

Boo

14^h33^m36.45^s / +35°35'08.00"

8^m.1

14^m.3

19.7"

335°

2013

8^m.1

14^m.7

36.6"

322°

2013

René Merting Drachhausen (Germany)	100mm (142x)	AB: bei 64x ein extrem dicht stehendes Pärchen, Trennung fast greifbar - bei 142x stehen die Sterne noch immer sehr eng, die Trennung ist nun aber eindeutig - Komponente B im NO ist etwas schwächer - beide Sterne leicht gelblich, hin und wieder mit Farbkontrast in Richtung orange
Uwe Pilz Leipzig (Germany)	105mm (288x)	AB: nicht getrennt
Mark McCarthy Fremont (California/USA)	203mm (205x)	AB: Nice white pair, ~1.5 delta mag, wide ~5". (Check the orbit on this one! Oh to be alive in the 3530s to see B whip around A)
Mark McCarthy Fremont (California/USA)	317mm (553x)	AC: 13th magnitude, a wide pair? Seen with averted vision, comes and goes with seeing

A347

8^m.7

8^m.4

0.5"

236°

2018

Boo

14^h36^m56.24^s / +48°13'17.90"

Mark McCarthy

Fremont (California/USA)

508mm (445x)

Near equal white stars, suspected double at 205x, easy split at 445x. Binary with 236.4-year period

★

STF1863

7^m.7

7^m.8

0.6"

63°

2018

Boo

14^h38^m00.71^s / +51°34'42.10"

Robert Zebahl Leipzig (Germany)	102mm (280x)	2021-05-16: The double star appeared elongated with an estimated position angle of 60°.
Christopher Hay Seeheim (Germany)	180mm (200x)	30 May 2021, current separation 0.65” according to Stelledoppie. No prior PA knowledge nor knowledge of relative brightnesses. Constant elongation seen. Definite determination of position of the primary within the elongation, more definite than the relative brightnesses (consulted after observation) would have led me to expect. PA estimated at 60°. In good moments fragments of a pear-shaped first diffraction ring surround the system, particularly on the side of the primary. An interesting and attractive sight.
Frederik Wanink Itterbeck (Germany)	254mm (640x)	gerade trennbar

STF1867

8^m.4

8^m.8

0.7"

355°

2017

Boo

14^h40^m44.21^s / +31°17'23.50"

Mark McCarthy Fremont (California/USA)	203mm (533x)	Hairline split best moments, noticeable mag difference
Mark McCarthy Fremont (California/USA)	317mm (553x)	0.5 delta mag, hair to figure 8 split, white.

STF1872

7^m.5

8^m.3

7.4"

50°

2019

Dra

14^h41^m00.84^s / +57°57'28.10"

7^m.5

10^m.6

75.7"

42°

2015

René Merting Drachhausen (Germany)	320mm (45x)	AB: bei 45x ist die B-Komponente nordöstlich über A erkennbar, ein Blatt Papier passt zwischen die beiden - leichter Farbunterschied - bei 72x zeigt sich ein gut getrenntes Pärchen, B ist eine dreiviertel Magnitude schwächer und blauweiß, A ist gelbweiß
Karsten Kopp Köln (Germany)	600mm (180x)	AB: Doppelstern ist gut zu trennen. Helligkeitsunterschied ist erkennbar, aber nicht besonders auffällig. Der hellere Stern erscheint weißgelblich und der schwächere gelblich.

★★

zeta Boo

STF1865

4^m.5

0.2"

278°

2020

Boo

14^h41^m08.92^s / +13°43'42.00"

H6 104

AB-C

4^m.5

11^m.0

104.3"

259°

2020

Uwe Pilz Leipzig (Germany)	105mm (88x)	AB-C
Uwe Pilz Leipzig (Germany)	120mm (250x)	AB
Mark McCarthy Fremont (California/USA)	508mm (1067x)	AB: Zeta Boo. Short period. First impression was moderately well notched overlapping disks (eg. not barely notched, but not strongly notched either). With more time observing & getting used to the image, and in moments of better seeing, the notch became more distinct. It would not separate in spite of moments of better seeing. I could also see the elongation, but only subtly notched due to the smaller scale, at 667x

STF1871

8^m.0

8^m.1

1.8"

313°

2019

Boo

14^h41^m35.50^s / +51°23'51.30"

Robert Zebahl

Leipzig (Germany)

102mm (187x)

2021-05-16: Clearly separated, but still pretty tight with similarly bright components.

STF1878, DL Dra

6^m.3

9^m.2

4.2"

314°

2019

Dra

14^h42^m03.25^s / +61°15'42.90"

Uwe Pilz Leipzig (Germany)	105mm (198x)	starke Aufhellung im ersten Ring
René Merting Drachhausen (Germany)	320mm (144x)	bei 144x sieht der Doppelstern genauso aus wie der benachbarte östlich stehende STF 1882 bei 45x - B steht knapp abgesetzt im Nordwesten von A und ist 2 Größenklassen schwächer (2.83 mag laut Stelle Doppie) - leichter Farbkontrast

★★

HU575

9^m.8

10^m.1

0.4"

284°

2017

Boo

14^h42^m33.63^s / +19°28'46.90"

Mark McCarthy

Fremont (California/USA)

508mm (1067x)

Short period. Small, faint, but definite split of these orange-red near equal stars. I sketched a clear orientation to field stars. Awesome

★

A1109

7^m.4

9^m.4

1.9"

88°

2017

Vir

14^h42^m47.60^s / +06°35'26.40"

Mark McCarthy

Fremont (California/USA)

203mm (333x)

Both stars light yellow, big magnitude difference, ~3-4 delta mag, about 2". Not difficult

STT285

7^m.8

8^m.7

0.5"

76°

2019

Boo

14^h45^m29.74^s / +42°22'56.40"

Mark McCarthy

Fremont (California/USA)

508mm (445x)

Nicely split white stars, 1 delta mag, noted the PA with drift. Short period, 88.993-year period, it is at apastron and will hang there for the next decade

STF1879

7^m.8

8^m.4

1.7"

82°

2018

Boo

14^h46^m15.58^s / +09°38'48.20"

Mark McCarthy Fremont (California/USA)	317mm (553x)	Fairly close yellow and orange-yellow, ~1 delta mag, ~3"
Karsten Kopp Köln (Germany)	600mm (180x)	Doppelstern konnte gerade so getrennt werden. Beide erscheinen weißlich.

★

STF1884

6^m.6

7^m.5

2.3"

55°

2020

Boo

14^h48^m23.37^s / +24°22'01.00"

Mark McCarthy Fremont (California/USA)	80mm (94x)	Extremely fine, 1 delta mag, notched, to overlapping disks at best moments. Physical with a 1398.2859-year period, it has a nearly edge-on orbit and is currently at the shorter of the two furthest reaches of its orbit
René Merting Drachhausen (Germany)	100mm (64x)	bei 64x ist der Doppelstern als 8 erkennbar, 107x reicht dann für die knappe Trennung - die B-Komponente im NO ist nur unwesentlich schwächer - ein sehenswertes Pärchen
Robert Zebahl Leipzig (Germany)	102mm (86x)	At 86x pretty tight and unequal. At 160x clearly split. A: white, B: slightly orange.
Mark McCarthy Fremont (California/USA)	203mm (333x)	Prototypical pair, >1 delta mag, ~3" separation, white to off white color
Frederik Wanink Itterbeck (Germany)	254mm (640x)	einfach
Karsten Kopp Köln (Germany)	600mm (180x)	Doppelstern konnte gerade so getrennt werden. Beide Sternen leuchten weißlich.

BU346

7^m.5

7^m.9

2.8"

277°

2020

Lib

14^h48^m31.71^s / -17°20'24.40"

Mark McCarthy

Fremont (California/USA)

317mm (553x)

Easy, well split, yellow-orange stars, half delta mag.

STF1883

7^m.0

8^m.9

1.0"

278°

2015

Vir

14^h48^m53.22^s / +05°57'15.90"

Mark McCarthy

Fremont (California/USA)

317mm (553x)

Strongly suspect a split / elongation in 80mm finder. In the scope it is a tight 2 delta mag orangish-white pair, ~1"

BU106, mu Lib, 7 Lib

5^m.6

6^m.6

1.9"

7°

2019

Lib

14^h49^m19.09^s / -14°08'56.30"

5^m.6

14^m.7

12.9"

294°

2000

5^m.6

14^m.1

25.7"

168°

2000

5^m.6

12^m.6

26.6"

232°

2015

Mark McCarthy Fremont (California/USA)	203mm (333x)	AB: Close, 1.5-2", half to one delta mag, off-white stars.
Gerd Kohler Langenzenn (Germany)	254mm (346x)	AB: Bläulich-weiß - bläulich-weiß. A und B haben nur einen geringen Helligkeitsunterschied.
Gerd Kohler Langenzenn (Germany)	254mm (346x)	AE: Bläulich-weiß - weiß. Stern E ist sehr schwach.
Frederik Wanink Itterbeck (Germany)	254mm (640x)	AB: getrennt, schwierig wegen Südlage

★

STF1890, 39 Boo

6^m.3

6^m.7

2.6"

46°

2020

Boo

14^h49^m41.37^s / +48°43'15.60"

Robert Zebahl Leipzig (Germany)	70mm (67x)	2020-04-01: At 44x elongated, partly notched. At 67x split, but very tight. A difference in brightness was not seen. At 133x clearly separated with little difference in brightness. A appeared pale yellow, B rather warm-white.
Robert Zebahl Leipzig (Germany)	70mm (100x)	2020-04-18: At 57x very finely separated with extremely tightly spaced components that appeared equally bright. At 100x a very nice pair with little difference in brightness. Fantastic sight! The color of the components was slightly different: creamy-white & a touch of yellow-orange.
Robert Zebahl Leipzig (Germany)	102mm (187x)	2021-05-16: Easy. Beautiful double star with slight difference in brightness. Yellowish & rather white. I estimated the position angle to 40°.
Frederik Wanink Itterbeck (Germany)	254mm (640x)	gleich hell
Mark McCarthy Fremont (California/USA)	317mm (553x)	Bright white pair, well split

★

xi Boo, 37 Boo

STF1888

4^m.8

7^m.0

5.2"

297°

2020

Boo

14^h51^m23.38^s / +19°06'01.70"

STF1888

4^m.8

13^m.8

71.3"

340°

2015

STF1888

4^m.8

11^m.7

160.8"

286°

2015

ARN11

4^m.8

8^m.7

271.5"

98°

2015

ARN11

4^m.8

9^m.2

335.4"

39°

2020

STF1888

7^m.0

13^m.8

63.9"

340°

2001

STF1888

7^m.0

8^m.7

273.5"

102°

2009

Robert Zebahl Leipzig (Germany)	70mm (44x)	AB: 2020-04-24: Beautifully separated with quite a large difference in brightness in a lovely star field. The primary component shines yellowish with a faint companion.
Mark McCarthy Fremont (California/USA)	80mm (94x)	AB: Yellow A and orange B, 2 delta mag, nice. Only 22 light years distant, it is physical with a 298-year period, and will tighten the next 30 years
Sarah Gebauer Germany	150mm (83x)	AB: die 6'' entfernten Komponenten A und B konnten mühelos bei 83x getrennt werden, Komponente E war zu sehen, C, D und F waren nicht sichtbar
Mark McCarthy Fremont (California/USA)	508mm (333x)	AB: Xi Boo. Short period. Richly colored yellow and orange stars, ~1 delta mag, ~5" separation, with several other stars in view. Very pretty
Karsten Kopp Köln (Germany)	600mm (180x)	AB: Ein recht schöner Doppelstern, wobei neben dem Helligkeitsunterschied von 2,2 mag auch die Sternfarben ein schönes Gesamtbild geben. Der hellere Stern erstrahlt gelblich weiß und der schwächere orangegelb. Hier handelt es sich auch um ein recht nahes System mit 21,9 Lichtjahren Entfernung.

Frederik Wanink

Itterbeck (Germany)

254mm

../projects/double-stars/frederik-wanink/photographs/Xi%20Bootis.jpg

★

STT287

8^m.4

8^m.6

0.6"

5°

2019

Boo

14^h51^m27.53^s / +44°55'42.60"

Mark McCarthy Fremont (California/USA)	317mm (553x)	Wow! Hair-split, ~0.7", near equal to half a delta mag.
Mark McCarthy Fremont (California/USA)	508mm (533x)	An elongated smear at 205x, split with seeing at 445x, stead split at 533x. <1", near equal white stars. Binary with 340-year period, currently tightening to periastron around 2044

★

BU31

8^m.5

10^m.3

2.0"

222°

2017

Boo

14^h52^m30.05^s / +18°44'19.50"

Mark McCarthy Fremont (California/USA)	203mm (333x)	White A and light yellow B, finely split, ~2 delta mag
Karsten Kopp Köln (Germany)	600mm (180x)	Doppelstern konnte gerade so getrennt werden. Die Distanz von 2,0 Bogensekunden und die Helligkeit beider Sterne, macht die Sichtung nicht leicht.

STT288

6^m.9

7^m.5

1.1"

160°

2019

Boo

14^h53^m23.35^s / +15°42'18.30"

Mark McCarthy Fremont (California/USA)	203mm (333x)	Consistent split, better with seeing, ~1 delta mag, ~1" separation, blue-white stars
Frederik Wanink Itterbeck (Germany)	254mm (640x)	rel. einfach
Mark McCarthy Fremont (California/USA)	317mm (553x)	Notched / figure 8 with 277x, split with 553x.
Mark McCarthy Fremont (California/USA)	317mm (553x)	Needed 553x to separate, resolved with the seeing. Near equal yellow-white, ~1" or less.

A1627

8^m.8

0.2"

200°

2016

Boo

14^h55^m46.57^s / +39°38'54.30"

Mark McCarthy

Fremont (California/USA)

508mm (889x)

Elongated at 533x, notched at 889x, stronger notch at 1334x. Light orange A, light blue B, equal magnitude. Currently 0.237", it has a 101.25-year period, seen nearly face in, and is at apastron to the SW and will make a quarter turn toward the W and tighten to <0.15" by 2041. Interestingly Gaia lacks data for these stars, so the orbit must be derived from historical measures only

HU907

10^m.2

0.2"

277°

2009

Boo

15^h00^m10.00^s / +21°28'48.80"

Mark McCarthy

Fremont (California/USA)

508mm (889x)

Very subtly notched olive, very tough. WDS says physical but Gaia lacks data on the stars

★

STF1909, 44 Boo

5^m.2

6^m.1

0.2"

138°

2020

Boo

15^h03^m47.30^s / +47°39'14.60"

Frederik Wanink Itterbeck (Germany)	254mm (640x)	2015 getrennt zu sehen (1")
Mark McCarthy Fremont (California/USA)	317mm (553x)	I Boo. Figure 8 to hair split, ~0.9". This pair shrinking separation fast, will be <0.5" in a couple of years. Only 40 LY away. (July 2017)

BU119

8^m.1

8^m.8

2.3"

274°

2019

Lib

15^h05^m31.91^s / -07°00'48.80"

Mark McCarthy

Fremont (California/USA)

203mm (333x)

Tried 667x at first but it was too much power, too dim and seeing too choppy. 333x was perfect, clean and well split ~2" near equal, slightly orange

★★

STFA27, delta Boo, 49 Boo

3^m.6

7^m.9

105.0"

78°

2021

Boo

15^h15^m30.16^s / +33°18'53.40"

Christopher Hay Seeheim (Germany)	15x45	Handheld, binoculars with internal stabilisation. Very wide. Component A is of a slight yellow-orange hue, its companion too weak (NELM in target area: 5m0) for colour impression. Nice in 4.5° FOV with Mu Boo AB, which is visibly slightly wider than Delta Boo and whose component B is slightly brighter than that of Delta Boo. Delta Boo is a physical double at a distance to us of 122 light years.
René Merting Drachhausen (Germany)	18x70	ein sehr ungleiches, weit auseinander stehendes Sternpaar - Komponente A im Westen strahlt gleißend cremegelb, die wesentlich schwächere Komponente B im Osten ist weißgrau bis bräunlich
Robert Zebahl Leipzig (Germany)	70mm (22x)	2020-04-24: Widely separated pair with large difference in brightness. Less striking. The bright primary component shines in a bright yellow.
Mark McCarthy Fremont (California/USA)	80mm (13x)	Split in 80mm finder. Very wide pair, very bright A, 3 delta mag B. Orange-yellow and blue-white B
Mark McCarthy Fremont (California/USA)	80mm (94x)	Delta Boo. Wide, large delta mag B, a 76,000-period pair!
Mark McCarthy Fremont (California/USA)	203mm (205x)	Bright star with many nearby faint stars. Didn't bother trying to figure out which are which.

Frederik Wanink

Itterbeck (Germany)

254mm

../projects/double-stars/frederik-wanink/photographs/Delta%20Bootis.jpg

STF1932

7^m.3

7^m.4

1.6"

267°

2019

CrB

15^h18^m20.19^s / +26°50'24.70"

Frederik Wanink Itterbeck (Germany)	254mm (640x)	gleich hell, getrennt
Mark McCarthy Fremont (California/USA)	317mm (553x)	Near equal yellow-white, very close but clean split, ~1.5". Nice!

★★★

mu Boo, 51 Boo, Alkalurops

CHR181, mu 1 Boo

Aa-Ab

4^m.3

0.1"

188°

2012

Boo

15^h24^m29.54^s / +37°22'37.10"

STFA28, mu 1 Boo

4^m.3

7^m.1

109.2"

171°

2020

STF1938, mu 2 Boo

Ba-Bb

7^m.1

7^m.6

2.2"

2°

2020

Christopher Hay Seeheim (Germany)	7x45	STFA28 (AB): Handheld. Wide split. A compact uneven pair. Component A is bluish-white. Rather charming in 8.6° FOV with Nu1/2 Boo, which has a gorgeous colour contrast, golden-orange and ice-blue, making it one of the strongest colour-contrast pairs in the sky for binoculars and greatly accentuating the sight of Mu Boo. In 15x45 binoculars STFA28 AB is very wide, component A bluish-white, B warmer.
Robert Zebahl Leipzig (Germany)	8x40	STFA28 (AB): Easily split with obvious difference in brightness.
Robert Zebahl Leipzig (Germany)	16x70	STFA28 (AB): 2021-06-14: Wide, relatively striking pair. Pale yellow & dark orange.
René Merting Drachhausen (Germany)	16x70	STFA28 (AB): weit getrenntes Pärchen, aufgrund der großen Helligkeitsunterschiedes schöner Farbkontrast - Komponente A im Norden gelblich, B im Süden mehr grau-braun
Robert Zebahl Leipzig (Germany)	70mm (22x)	STFA28 (AB): Evident, very wide apart and unequal. A: white-yellowish, B: grey.
Mark McCarthy Fremont (California/USA)	80mm (94x)	STFA28 (AB): Alkalurops Bright yellow-white A and bluish B, which is itself a slightly unequal close double, finely split (STF 1938 Ba,Bb) -- 256.5-year period, now coming off apastron
Robert Zebahl Leipzig (Germany)	102mm (125x)	Beautiful view! This triple system includes STFA 28 and STF 1938.
Uwe Pilz Leipzig (Germany)	105mm (288x)	ein heller 4m und zwei nahe dunkle 7m, lohnend.
Robert Zebahl Leipzig (Germany)	120mm (23x)	STFA28 (AB): Easy to split with large angular distance and noticeable difference in brightness.
Sarah Gebauer Germany	150mm (125x)	A-BC mit 109'' sind bei 125x sehr weit getrennt, es ist der Ansatz eines engen Doppelsterns zu erkennen, der sich mit 2,2'' Abstand auch bis 250x nicht auftrennen ließ
Christopher Hay Seeheim (Germany)	180mm (105x)	STF1938 (Ba-Bb): At 105x in poor seeing a kissing, evenly matched pair. At 180x clearly split despite the poor seeing, southern component (Ba) seems slightly brighter than Bb.
Mark McCarthy Fremont (California/USA)	203mm (205x)	STFA28 (AB): Bright A star does not seem round. The B star is a tight equal pair, pretty set. [Aa,Ab is CHR 181 0.1", and I'd be shocked if I actually detected it. STFA 28 is technically the bright star and the tight pair, the tight pair is Ba,Bb = STF 1938, 7.09/7.63, 2.2"]
Mark McCarthy Fremont (California/USA)	203mm (205x)	STFA28 (AB): Bright A star does not seem round (CHR181). B star is a tight equal pair (STF1938 Ba-Bb). Pretty set. STFA 28 is technically the bright star and the tight pair
Mark McCarthy Fremont (California/USA)	203mm (205x)	CHR181 (Aa-Ab): Bright A star does not seem round (CHR181). B star is a tight equal pair (STF1938 Ba-Bb). Pretty set. STFA 28 is technically the bright star and the tight pair
Mark McCarthy Fremont (California/USA)	203mm (205x)	STF1938 (Ba-Bb): Bright A star does not seem round (CHR181). B star is a tight equal pair (STF1938 Ba-Bb). Pretty set. STFA 28 is technically the bright star and the tight pair
Frederik Wanink Itterbeck (Germany)	254mm (640x)	STF1938 (Ba-Bb): 3er System, schön
Mark McCarthy Fremont (California/USA)	317mm (277x)	STFA28 (AB): Bright white star with tight yellow pair STF 1938 as its companion.
Mark McCarthy Fremont (California/USA)	317mm (553x)	STFA28 (AB): Striking. Bright star with near equal double STF 1938 paired with it. A star is a spectroscopic binary
Mark McCarthy Fremont (California/USA)	317mm (553x)	STF1938 (Ba-Bb): Near equal close but well split double also paired with STFA28
Karsten Kopp Köln (Germany)	600mm (257x)	Hier handelt es sich um ein Dreifachsternsystem, welches jetzt aber nicht durch eine besondere Färbung der Sterne auffällt. Die A - B/C Komponenten stehen noch sehr weit auseinander, wobei auch die A-Komponente um einiges heller erscheint. Die beiden Komponenten B/C sind wesentlich näher beieinander und unterscheiden sich auch kaum in ihrer Helligkeit.

HU149

7^m.5

7^m.6

0.7"

272°

2017

Dra

15^h24^m35.30^s / +54°12'46.10"

Frederik Wanink

Itterbeck (Germany)

254mm (640x)

mit Zwischenraum zu sehen

../projects/double-stars/frederik-wanink/sketches/HU149.jpg

★★

STT296

7^m.8

9^m.1

2.3"

273°

2020

Boo

15^h26^m26.56^s / +44°00'13.20"

7^m.8

12^m.7

80.7"

313°

2016

Mark McCarthy Fremont (California/USA)	203mm (205x)	AB: Very fine but well split, ~2", yellow-white A, reddish B, 2 delta mag.
Mark McCarthy Fremont (California/USA)	317mm (553x)	AB: Very beautiful, 2", 2 delta mag, with very faint third (AC) seen with averted vision widely separated.
Mark McCarthy Fremont (California/USA)	317mm (553x)	AC: Very beautiful, 2", 2 delta mag, with very faint third (AC) seen with averted vision widely separated.
Mark McCarthy Fremont (California/USA)	317mm (553x)	AB: Close near equal, 1 delta mag, white.

A1120

8^m.5

9^m.1

0.3"

334°

2018

Ser

15^h27^m18.03^s / +09°42'01.10"

Mark McCarthy

Fremont (California/USA)

508mm (889x)

Fairly strong notch but no split, not separated, snowman PA to west of north, >1 delta mag. Physical with 51.75-year period, grade 3 orbit (likely), 0.246" now. It is now coming off apastron and will close by the early 2030s, detectible visually again by 2045 or so

STF1944

8^m.3

8^m.8

0.7"

293°

2019

Ser

15^h27^m42.14^s / +06°06'04.50"

Mark McCarthy

Fremont (California/USA)

178mm (445x)

Hairline split wit seeing, significant magnitude difference, difficult. Physical with a 1030-year period, on the historical measures alone since there is no Gaia data for the secondary. It will continue to tighten to 0.4" by 2090, moving in the fastest part of its orbit

HU1163

9^m.2

9^m.7

0.3"

178°

2015

Boo

15^h30^m44.95^s / +38°09'48.70"

Mark McCarthy

Fremont (California/USA)

508mm (667x)

Barest hairline split at the best moments, snowman otherwise, very noticeable magnitude difference, PA to south. 0.257" now, it will widen slightly the next 30 years, reaching apastron around 2090 at ~0.4". Grade 3 orbit, 217-year period

COU798

9^m.5

9^m.8

0.2"

204°

2012

CrB

15^h34^m40.64^s / +26°54'42.80"

Mark McCarthy

Fremont (California/USA)

508mm (889x)

Barest of notches, white stars, noticeable magnitude difference. PA to the south. It's in the same low power (205x) field of view with Gemma, alpha CrB, so it looks like a piece of debris from the bright star explosion as seen in the eyepiece. Grade 4 orbit, 0.256" now, will widen only slightly by 2050 apastron. 154.7-year period

STF1954, delta Ser, 13 Ser

4^m.2

5^m.2

4.0"

171°

2020

Ser

15^h34^m48.14^s / +10°32'20.00"

4^m.2

13^m.9

66.6"

18°

2014

13^m.9

14^m.6

4.0"

341°

2018

Robert Zebahl Leipzig (Germany)	70mm (57x)	AB: Easy to separate with relatively close components and a clear difference in brightness. A appeared rather white, B slightly orange.
René Merting Drachhausen (Germany)	100mm (107x)	AB: bei 142x zwei gut getrennte reinweiße Komponenten - B wirkt eine halbe Größenklasse schwächer - zurück auf 107x ist die Trennung ebenfalls einfach - zurück auf 64x ist es eine 8 mit tiefen Einschnürungen, kurz vor der Trennung
Stefan Loibl Rosenheim (Germany)	102mm (102x)	AB: sparse field
Sarah Gebauer Germany	150mm (85x)	AB: Mit 85x schon schön getrennt, ein leichter Größenunterschied der Sterne zu erkennen, einige schwache Feldsterne im Okular bei 0,95° Gf.
Frederik Wanink Itterbeck (Germany)	254mm (640x)	AB: getrennt, Del Ser

★

STT298

7^m.2

8^m.4

1.2"

187°

2018

Boo

15^h36^m02.22^s / +39°48'08.90"

AB-C

6^m.9

7^m.8

120.4"

328°

2017

AB-D

6^m.9

13^m.9

167.4"

224°

2002

AB-E

6^m.9

12^m.1

456.0"

335°

2002

Robert Zebahl Leipzig (Germany)	102mm (28x)	AB-C: Wide, moderately unequal pair. Little difference in color: Primary components appeared a bit more orange colored.
Robert Zebahl Leipzig (Germany)	120mm (23x)	AB-C: Easy to split with large angular distance and noticeable difference in brightness.
Mark McCarthy Fremont (California/USA)	203mm (205x)	AB: At zenith, but worth the effort to slew to. Another great 2+1. The tight pair [AB] is near equal and split a little more than a hairline
Mark McCarthy Fremont (California/USA)	317mm (553x)	AB: One component of compicated 6 star system, some of which is split in 80mm finter. This is a close equal pair, ~2".

★★

STF1964 & HU1167

HU1167

8^m.1

9^m.9

1.4"

80°

2016

CrB

15^h38^m12.91^s / +36°14'48.60"

STF1964

8^m.1

14.5"

90°

2017

STF1964

8^m.1

9^m.0

15.1"

84°

2018

STF1964

8^m.1

9^m.0

1.5"

21°

2019

Robert Zebahl Leipzig (Germany)	16x70	STF1964 (AC): 2021-06-13: Beautiful double star with components of almost equal brightness and subtle color difference: white-bluish & slightly orange.
René Merting Drachhausen (Germany)	18x70	STF1964 (AC): zu erkennen sind zwei gleich helle, sehr dicht stehende Sterne - Trennung ein wenig mehr als knapp
René Merting Drachhausen (Germany)	100mm (20x)	STF1964 (AC): bei 20x ein gut getrenntes Pärchen gleich heller Sterne, auffallend im Sternumfeld
Robert Zebahl Leipzig (Germany)	102mm (62x)	STF1964 (AC): Rather wide pair, equal without visible difference in color.
Uwe Pilz Leipzig (Germany)	105mm (16x)	Dreifachstern nicht trennbar
Robert Zebahl Leipzig (Germany)	120mm (23x)	STF1964 (AC): Nice double star, well split with equally bright components.
Mark McCarthy Fremont (California/USA)	317mm (277x)	STF1964 (AC): Well split equal pair. I suspect B is pair as it is an elongated orange smear at 277x -- it is STF 1964CD.
Mark McCarthy Fremont (California/USA)	317mm (553x)	STF1964 (CD): Faint near equal pair about 3" separation. In the same field with HU 1167. Magnificent
Mark McCarthy Fremont (California/USA)	317mm (553x)	HU1167 (AB): Bright star with much fainter pair, about 1" separation, 3-4 delta mag. In same field with STF 1964. Magnificent

COU612

9^m.2

9^m.0

0.3"

342°

2016

CrB

15^h39^m02.60^s / +25°44'47.00"

Mark McCarthy

Fremont (California/USA)

508mm (889x)

Very slight elongation all powers, PA N-S but can't tell A from B. Physical with 63.09-year period, it's coming off apastron and will be difficult to detect visually until the 2060s

STF1989, pi UMi

7^m.3

8^m.2

0.7"

23°

2013

UMi

15^h39^m38.61^s / +79°58'59.60"

Frederik Wanink

Itterbeck (Germany)

254mm (640x)

blickweise als 8 zu sehen, schwierig

../projects/double-stars/frederik-wanink/sketches/pi2Umi.jpg

★

STF1967, 8 CrB, gamma CrB

4^m.0

5^m.6

0.5"

110°

2015

CrB

15^h42^m44.57^s / +26°17'44.30"

Robert Zebahl Leipzig (Germany)	152mm (300x)	2021-07-23: Gamma CrB was only a few degrees above the house roof and the refractor was insufficiently cooled down. In no way visible as a double star. I used magnifications from 200x to 400x.
Mark McCarthy Fremont (California/USA)	203mm (667x)	Definite mis-shape, oval to egg, observation made June 2019

STF1985

7^m.0

8^m.7

6.2"

354°

2020

Ser

15^h55^m54.63^s / -02°09'51.30"

Mark McCarthy

Fremont (California/USA)

178mm (205x)

Ice blue color A and slightly red B, >1 delta mag, pretty wide. 2307.2358-year period, it will slowly widen

STT303

7^m.7

8^m.1

1.6"

175°

2019

Ser

16^h00^m54.16^s / +13°16'18.20"

Mark McCarthy

Fremont (California/USA)

317mm (553x)

Near equal white, ~1.5". Nice!

S676, rho CrB

5^m.5

10^m.5

141.4"

47°

2020

CrB

16^h01^m02.65^s / +33°18'12.60"

Mark McCarthy

Fremont (California/USA)

508mm (667x)

Rho CrB. bright orange star with very obvious wide B, 3 delta mag

STF2028

9^m.9

9^m.1

0.5"

147°

2016

CrB

16^h12^m48.11^s / +39°21'35.60"

Mark McCarthy

Fremont (California/USA)

508mm (533x)

Nice delicate split with 445x, well split clean with 533x, white stars, ~1 delta, PA to SE. Grade 3 orbit, 105.34-year period, 0.519" now it's at apastron now and will sit there until 2050 when it will start close again in its nearly edge-on orbit

★

STF2021, 49 Ser

7^m.4

7^m.5

4.0"

358°

2019

Her

16^h13^m18.45^s / +13°31'37.20"

Robert Zebahl Leipzig (Germany)	70mm (57x)	Lovely split. Almost equal pair with relatively close components.
René Merting Drachhausen (Germany)	100mm (64x)	bei 32x zeigen sich zwei gleich helle weiße Sterne, die sich gerade noch berühren - bei 64x dann knappe Trennung, B ist nur minimal schwächer
Mark McCarthy Fremont (California/USA)	203mm (205x)	49 Ser. Light yellow orange, near equal, bright, wide ~4". Physical, 1354 year period
Karsten Kopp Köln (Germany)	600mm (180x)	Doppelstern ist gut zu trennen, bei fast identischer Helligkeit. Ein weißliches Augenpaar schaut mich an.

A1642

8^m.9

9^m.4

0.8"

181°

2016

Her

16^h13^m43.62^s / +46°38'23.10"

Mark McCarthy

Fremont (California/USA)

508mm (333x)

Momentarily split with seeing, ~2 delta mag, <1". 188 year period

RST3936 & STF2019

RST3936

8^m.2

8^m.4

0.3"

269°

2018

Sco

16^h14^m16.53^s / -10°24'52.00"

STF2019

AB-C

7^m.4

9^m.8

22.3"

153°

2018

René Merting

Drachhausen (Germany)

15x56

STF2019 (AB-C): es dauert, aber irgendwann ist Komponente B sehr schwach knapp getrennt südöstlich von A erkennbar - mitunter dauert es, bis man B wiederfindet, wenn man neu ansetzt

sigma CrB, 17 CrB, STF2032

5^m.6

6^m.5

7.2"

240°

2021

CrB

16^h14^m40.85^s / +33°51'31.00"

Robert Zebahl Leipzig (Germany)	16x70	2021-06-13: Clearly recognizable as a double star with a well visible difference in brightness. It appears clearly as '8' and is close to be separated.
Robert Zebahl Leipzig (Germany)	70mm (22x)	At 22x clearly separated, but very close with a clear difference in brightness. At 57x easy without any noticeable difference in color.
René Merting Drachhausen (Germany)	100mm (32x)	bei 20x zwei knapp zusammenstehende Sterne mit tiefer Einschnürung - bei 32x dann ein knapp getrenntes Pärchen - B-Komponente südwestlich gut eine halbe Größenklasse schwächer - beide Sterne mit weißem Brautkleid
Stefan Loibl Rosenheim (Germany)	102mm (26x)	Already split at 26x. Component A orange, B yellow.
René Merting Drachhausen (Germany)	320mm (72x)	bei 72x ein schick anzusehendes, knapp getrenntes Pärchen - A im Osten ist hellgelb - B ist vielleicht eine halbe Größenklasse schwächer und auch gelblich, aber nicht so stark wie A
Mark McCarthy Fremont (California/USA)	508mm (667x)	Sigma CrB. AB nice bright half delta mag wide. two more stars in system, one (AC) closer fainter, other (AD) further away.
Karsten Kopp Köln (Germany)	600mm (135x)	Sehr einfaches, auffälliges Objekt im Okular, ansonsten keine weiteren Auffälligkeiten.

STF2026

9^m.5

9^m.9

3.5"

16°

2019

Her

16^h15^m57.07^s / +07°21'24.80"

René Merting Drachhausen (Germany)	100mm (107x)	bei 64x sind die Sterne so schwach, dass ich hellere Sterne im Umfeld zum Fokussieren nutzen muss - beide Komponenten sind als 8 erkennbar, die Einschnürung ist aber nur in guten Momenten da - bei 107x dann gelingt die Trennung, B wirkt deutlich schwächer (in Wirklichkeit ist B nur 0m4 schwächer), aber vielleicht liegt es daran, dass die beiden Sterne ohnehin nur sehr schwach beobachtbar sind - das hat wenig Freude bereitet
Mark McCarthy Fremont (California/USA)	178mm (205x)	Wide, <1 delta mag white stars. 433.7911-year period it is approaching apastron. The AC pair is LEP 78 AC, sep 581.7 mag 9.48,17.49, discovered in 2000, which claims to be physical, however Gaia data shows there is no overlap in the parallax ranges and even the proper motions are divergent

KUI72

5^m.5

10^m.0

3.2"

125°

2016

Her

16^h19^m55.24^s / +39°42'30.90"

Mark McCarthy

Fremont (California/USA)

317mm (553x)

Distinct faint point appears with perfect seeing ~2-3". Much smaller and fainter than A.

★★★

rho Oph, 5 Oph

H2 19

5^m.1

5^m.7

3.0"

335°

2021

Oph

16^h25^m35.03^s / -23°26'47.00"

H2 19

5^m.1

7^m.3

151.1"

0°

2021

H2 19

5^m.1

6^m.8

156.1"

253°

2021

KOU63

5^m.8

11^m.7

4.8"

206°

2000

BU1115

6^m.8

8^m.4

0.3"

196°

2018

Stefan Loibl

Rosenheim (Germany)

102mm (102x)

AB: possible components (DE) and (CF) already visible at 27x magnification with ca. 2 arcmin distance

★

STF2052

7^m.7

7^m.9

2.5"

118°

2020

Her

16^h28^m52.67^s / +18°24'50.60"

7^m.7

11^m.8

141.4"

41°

2015

René Merting Drachhausen (Germany)	76mm (95x)	AB: bei 57x kann ich eine schwache 8 erkennen, die beiden gleich schwachen Sterne stehen kurz vor der Trennung - bei 95x dann sind beide Komponenten knapp getrennt sichtbar
René Merting Drachhausen (Germany)	100mm (107x)	AB: bei 64x zwei gleichhelle Sterne, die sich gerade so berühren - bei 107x ein knapp getrenntes Pärchen, Komponente B im SO ist nur marginal schwächer
Stefan Loibl Rosenheim (Germany)	102mm (102x)	AB: Does not appear as a multiple star at 28x, elongated at 68x, splith with 102x. Component A blueish, B reddish. Observation of component C questionable. Occasional observation of a star at the presumably correct position.
Mark McCarthy Fremont (California/USA)	317mm (277x)	AB: Pretty pale yellow-orange pair of equal magnitude, about 2" separation.
Karsten Kopp Köln (Germany)	600mm (180x)	AB: Doppelstern war noch gut zu trennen, bei fast identischer Helligkeit. Komponente A wirkt weißlich, während die etwas schwächere Komponente B gelblich orange strahlt.

alpha Sco, 21 Sco, Antares, GNT1

1^m.0

5^m.4

2.7"

277°

2019

Sco

16^h29^m24.47^s / -26°25'55.00"

Mark McCarthy

Fremont (California/USA)

80mm (133x)

A shows as an airy disk with tremulous diffraction rings, but the very faint B star was steady within the diffraction ring. Current separation is 3.2" and its PA is to the west, which matched what I saw. A star is a bright orange, B is light green but faint

★

lambda Oph, 10 Oph, STF2055, Marfic

4^m.2

5^m.2

1.4"

44°

2019

Oph

16^h30^m54.84^s / +01°59'02.80"

Stefan Loibl Rosenheim (Germany)	102mm (205x)	components cannot be split at 205x
Uwe Pilz Leipzig (Germany)	105mm (288x)	schöner Farbkontrast, lohnend.
Sarah Gebauer Germany	150mm (160x)	habe den Doppelstern zwar gefunden und konnte auch erkennen, dass es zwei Sterne sind, eine Trennung war aber heute Abend nicht möglich
Mark McCarthy Fremont (California/USA)	203mm (205x)	Marfic. Nice blazing white pair, ~1 delta, ~2". 129 year period, but not much change in the next few years
Frederik Wanink Itterbeck (Germany)	254mm (640x)	getrennt

★

STF2059

8^m.8

0.3"

179°

2016

Her

16^h30^m55.71^s / +38°03'52.60"

Frederik Wanink Itterbeck (Germany)	254mm (640x)	nicht als DS gesehen
Mark McCarthy Fremont (California/USA)	317mm (553x)	Overlapping disks, notched. Need perfect seeing. This was 1.2" at Struve's discovery, so easier for him to see -- I doubt he would have found it now, near its closest separation. August 2017

★

STF2084, zeta Her, 40 Her

3^m.0

5^m.4

1.6"

110°

2019

Her

16^h41^m17.16^s / +31°36'09.80"

Sarah Gebauer Germany	100mm (136x)	auf Anhieb ganz haarscharf getrennt, aber leider nur wenige Sekunden haltbar; dennoch erfolgreiche Trennung!
Robert Zebahl Leipzig (Germany)	102mm (224x)	Faint companion as distinct brightening on the first diffraction ring visible. In steadier moments visible as small, round condensation.
Robert Zebahl Leipzig (Germany)	102mm (280x)	After a longer, concentrated observation, a permanent brightening of the first diffraction ring of the primary component could be seen at the correct position angle. The brightening appeared only arch-shaped without any noticeable condensation.
Uwe Pilz Leipzig (Germany)	105mm (288x)	äußerst schwierig
Uwe Pilz Leipzig (Germany)	105mm (288x)	Bei sehr ruhiger Luft ohne Probleme sichtbar, trotz der störenden Restkoma meines Refraktors
Mark McCarthy Fremont (California/USA)	152mm (285x)	Zeta Her. A lot of diffraction but there is a persistent bulge, brightening to a split, at the first diffraction ring. Suspected at 175x
Mark McCarthy Fremont (California/USA)	203mm (533x)	Zeta Her. B was seen, not too difficult as a disk within the diffraction of bright A, just outside first ring so ~1.5", like a diamond ring, significant mag difference
Frederik Wanink Itterbeck (Germany)	254mm (640x)	nicht als DS gesehen
Frederik Wanink Itterbeck (Germany)	254mm (640x)	getrennt
René Merting Drachhausen (Germany)	320mm (320x)	in der Nacht konnte ich nur bis 320x gewinnbringend vergrößern - Komponente A zeigt schöne Beugungsscheibchen, B offenbarte sich mir nicht

A349

10^m.7

10^m.9

0.7"

127°

2018

Her

16^h41^m17.67^s / +30°06'36.20"

Mark McCarthy

Fremont (California/USA)

203mm (333x)

V908 Her. Elongation with averted vision, can't coax any better view. Light yellow. Physical, 135.69 year period

STF2091

8^m.4

9^m.3

0.4"

328°

2012

Her

16^h42^m09.74^s / +41°11'42.90"

Frederik Wanink Itterbeck (Germany)	254mm (640x)	nicht als DS gesehen
Mark McCarthy Fremont (California/USA)	317mm (553x)	I "see" rod shape once I know it is 0.4" separation. Marginal. (This one 1.3" at Struve's discovery, so easy for him! August 2017)

D15

9^m.0

9^m.3

0.6"

335°

2016

Her

16^h43^m56.29^s / +43°28'31.20"

Mark McCarthy Fremont (California/USA)	317mm (553x)	Light orange elongated, with notch, near equal. (0.9" at discovery).
Mark McCarthy Fremont (California/USA)	508mm (333x)	Close split with seeing, slight mag difference, ivory white stars

★★

52 Her

BU627

A-BC

4^m.8

8^m.4

2.2"

44°

2018

Her

16^h49^m14.21^s / +45°58'59.90"

A1866

9^m.5

9^m.6

0.3"

267°

2013

René Merting Drachhausen (Germany)	100mm (142x)	BU627 (A-BC): bis 142x probiert, hat nicht funktioniert - der Helligkeitsunterschied ist vermutlich zu groß und das Beugungsscheibchen von A so hell wie BC selbst
Robert Zebahl Leipzig (Germany)	102mm (280x)	BU627 (A-BC): At 160x the faint component is already beginning to be visible as brightening in the first diffraction ring. At 280x the brightening is quite clearly visible and appears partly clear as a small knot in the first diffraction ring.
Uwe Pilz Leipzig (Germany)	105mm (288x)	BU627 (A-BC)
Uwe Pilz Leipzig (Germany)	120mm (180x)	BU627 (A-BC)
Mark McCarthy Fremont (California/USA)	317mm (553x)	BU627 (A-BC): 52 Her. Very bright white star with a companion disk 2", 4-5 delta mag. Wow! B appears as if it is illuminated by A's light. Did not detect BC, 0.3"

★★

STF2107

6^m.9

8^m.5

1.4"

112°

2020

Her

16^h51^m50.10^s / +28°39'58.70"

Mark McCarthy Fremont (California/USA)	152mm (175x)	! Extremely fine hairline split with seeing, 1.5 delta mag white stars. Obvious split with 285x. Physical with a 274 year orbit, now at apastron. 1.1" at discovery in 1828
Mark McCarthy Fremont (California/USA)	317mm (553x)	Yellow and orange pair, very close ~1.5", 1 delta mag. Very pretty.
Mark McCarthy Fremont (California/USA)	508mm (667x)	Nice pair yellow and slightly blue two delta mag, about 1.5" (AC is 11.5 and much further separated)
Karsten Kopp Köln (Germany)	600mm (385x)	Doppelstern ist bei 180-facher Vergrößerung gerade so als 8 zu erkennen. Bei 385-facher Vergrößerung in den seltenen Augenblicken des ruhigen Seeings gerade so eben zu trennen. Sehr schwierig auch wegen des Helligkeitsunterschied von 1,6 mag.

STF2118, 20 Dra

7^m.1

7^m.3

0.9"

65°

2018

Dra

16^h56^m25.32^s / +65°02'20.60"

Frederik Wanink

Itterbeck (Germany)

254mm (640x)

sehr einfach

../projects/double-stars/frederik-wanink/sketches/20Dra.jpg

STF2128

8^m.8

10^m.3

12.2"

42°

2019

Dra

17^h03^m18.66^s / +59°35'07.30"

Mark McCarthy

Fremont (California/USA)

508mm (205x)

Wide stars, light orange, ~2 delta mag. 1200 year period

★★

mu Dra, 21 Dra, Alrakis, Arrakis

STF2130

5^m.7

2.5"

358°

2020

Dra

17^h05^m20.20^s / +54°28'14.30"

BU1088

5^m.7

13^m.7

12.2"

174°

2015

Christopher Hay Seeheim (Germany)	80mm (100x)	In May 2019 neatly split, no colours seen. A physical system with a period of 812 years. Periastron was in 1946, since then the distance is widening to reach 2.7“ in 2025 and 2.8“ in 2030
René Merting Drachhausen (Germany)	100mm (107x)	AB: bei 107x zeigen sich zwei knapp getrennte Perlchen, beide gleichhell und weiß schimmernd - ein schickes Paar
Robert Zebahl Leipzig (Germany)	102mm (125x)	AB: Easy to separate. Beautiful sight. Components equally bright with no discernible color difference.
Uwe Pilz Leipzig (Germany)	105mm (144x)	AB
Mark McCarthy Fremont (California/USA)	203mm (205x)	AB: Mu Dra. "Arrakis" (which was the name of the planet in the book Dune, but means "Dancer" in Arabic). Light yellow-orange stars, well split, equal. 812 year period
Frederik Wanink Itterbeck (Germany)	254mm (460x)	AB: gleich hell

A1145

6^m.3

7^m.8

0.7"

340°

2018

Oph

17^h08^m13.65^s / -01°04'46.10"

Mark McCarthy

Fremont (California/USA)

203mm (667x)

Marginal observation of a very faint, very close-in star which briefly resolves as a point and not a flare.

eta Oph, 35 Oph

BU1118

3^m.0

3^m.3

0.5"

228°

2019

Oph

17^h10^m22.66^s / -15°43'30.50"

BU1118

AB-C

2^m.4

12^m.3

99.8"

148°

2012

BU1118

2^m.4

11^m.2

101.2"

281°

2012

DAL52

2^m.4

11^m.1

62.7"

317°

2012

Stefan Loibl

Rosenheim (Germany)

102mm (205x)

B component recognizable in the airy disk, E component not visible

STF2135

7^m.6

8^m.9

8.7"

195°

2018

Her

17^h12^m06.06^s / +21°13'44.40"

7^m.6

12^m.9

162.1"

208°

2015

René Merting Drachhausen (Germany)	100mm (32x)	AB: bei 64x ein locker getrenntes Pärchen - Komponente B im Süden halb so hell wie A - zurück auf 32x sind beide Sterne als enges Pärchen erkennbar, nicht zu knapp getrennt - noch weiter zurück auf 20x sehe ich ein längliches Sternchen, Trennung bei dieser Vergrößerung noch nicht möglich
Mark McCarthy Fremont (California/USA)	203mm (667x)	AB: Pretty yellow star with widely separated 2 delta mag bluish B. (Not physical)

KUI79

10^m.0

10^m.2

0.7"

289°

2018

Her

17^h12^m07.78^s / +45°39'57.60"

Mark McCarthy

Fremont (California/USA)

508mm (333x)

Fine split ~1", noticeable mag difference. 12.91 year period!

★★

STF2140, alpha Her, 64 Her, Ras Algethi

3^m.5

5^m.4

4.7"

103°

2020

Her

17^h14^m38.86^s / +14°23'24.90"

Christopher Hay Seeheim (Germany)	36mm (50x)	At 50x secondary detaches momentarily from first diffraction ring of primary as the tiniest pinprick of light, delta-mag seems massive. At 66x separation becomes much clearer. Can hold secondary 80% of the time as a fine point on the outer rim of the first diffraction ring. Primary is orange-yellow, secondary far too faint in this aperture for any kind of colour impression. Rather charming in a strange sort of way. See for comparison simultaneous observation with 210mm at 68x.
Robert Zebahl Leipzig (Germany)	55mm (41x)	Well split with noticeable difference in brightness.
René Merting Drachhausen (Germany)	100mm (64x)	bei 32x ist noch nichts erkennbar - bei 64x wird östlich von Rasalgethi der schwache Begleiter B knapp getrennt sichtbar - A ist strahlend gelb, B mit einer Tendenz zum gelb, eher ein warmes weiß
Uwe Pilz Leipzig (Germany)	105mm (88x)	himmelblau und hellgelb, getrennt bei 53x
Uwe Pilz Leipzig (Germany)	105mm (288x)	gelb-lachsfarben
Robert Zebahl Leipzig (Germany)	120mm (100x)	Easily split with noticeable difference in brightness. A: intensively orange colored, B: slightly orange.
Karsten Kopp Köln (Germany)	140mm (94x)	Konnte erst mit 94-facher Vergrößerung gut getrennt wahrgenommen werden.
Sarah Gebauer Germany	150mm (85x)	bei Halbmond auf der Schwäbischen Alb: sehr eng, aber sauber getrennt, eine Komponente ist viel heller und größer, mein Farbeindruck ist allerdings unerwartet eher gelb
Sarah Gebauer Germany	150mm (160x)	richtig gold, es strahlt mich richtiggehend an, auch sehr schön getrennt, ein toller Doppelstern!
Mark McCarthy Fremont (California/USA)	152mm (175x)	Rasalgethi. Wow best ever view, perfect disks with no flaring. Light orange A and 2 delta mag light aqua B. Physical with a 3600-year period
Mark McCarthy Fremont (California/USA)	203mm (667x)	Rasalgethi. 8" inch mask due to seeing. AB orange and blue 4 delta mag. Faint AD seen very wide separation. pretty star.
Christopher Hay Seeheim (Germany)	210mm (68x)	Despite the primary being a little bloated in mediocre seeing, the secondary is set off clearly as a fine pinprick of light. Both are orangish-yellow. A very charming sight. See for comparison simultaneous observation with 36mm at 66x.
Frederik Wanink Itterbeck (Germany)	254mm (640x)	gelblich und bläulicher Stern
Mark McCarthy Fremont (California/USA)	317mm (277x)	Rasalgethi, Bright orange A & pale green much fainter B. Very nice!
Karsten Kopp Köln (Germany)	600mm (135x)	Leicht zu trennen. Komponente A erscheint orange, Komponente B gelblich.
Karsten Kopp Köln (Germany)	600mm (180x)	Doppelstern ist gut zu trennen. Komponente A erstrahlt orange und Komponente B gelblich.

Frederik Wanink Itterbeck (Germany)	254mm
Jens Leich Germany	130mm

SHJ243, 36 Oph

5^m.1

5.1"

138°

2021

Oph

17^h15^m20.78^s / -26°36'06.10"

5^m.1

6^m.5

732.5"

74°

2021

5^m.1

7^m.8

295.5"

342°

2021

5^m.1

12^m.3

38.2"

313°

2000

Stefan Loibl

Rosenheim (Germany)

102mm (68x)

Komponente AB separated at 68x magnification, componente C at greater distance of 12.2 arcmin

STF2153

9^m.4

9^m.7

1.6"

244°

2020

Her

17^h17^m53.03^s / +49°18'18.50"

Mark McCarthy

Fremont (California/USA)

203mm (333x)

Near equal, ~2", white

★★★

BU628

9^m.5

9^m.6

0.6"

262°

2016

Her

17^h18^m22.22^s / +32°39'38.50"

Mark McCarthy

Fremont (California/USA)

508mm (1067x)

Wow split clean, amazing. No resolution at 667x but at 1067x two airy disks, sep by half disk, half delta mag. Remarkable

DON832, xi Oph

4^m.4

8^m.9

4.1"

26°

2016

Oph

17^h21^m00.37^s / -21°06'46.50"

Stefan Loibl

Rosenheim (Germany)

102mm (205x)

fainter 9 mag component not visible

★

COU415

8^m.8

9^m.8

0.3"

342°

2012

Her

17^h22^m04.55^s / +23°09'40.40"

Mark McCarthy

Fremont (California/USA)

508mm (1067x)

Notched elongation at 533x & 667x. I get an instantaneous split with perfect seeing at 1067x, it stays notched. ~1 delta. 90 year period.

BU1250

10^m.8

11^m.1

1.9"

118°

2015

Her

17^h24^m49.67^s / +30°44'24.00"

Mark McCarthy

Fremont (California/USA)

178mm (205x)

Can see it steadily split at small scale at 205x, bluish stars at one corner of a triable of near equal magnitude stars. I get a wider split but needing more averted vision at 445x. Discovered with his 6-inch, Burnham notes: "It is the s star of a small equilateral triangle, all in the field." No parallax overlap, not physical

A351

9^m.7

9^m.9

0.5"

58°

2016

Her

17^h29^m20.05^s / +29°23'30.80"

Mark McCarthy

Fremont (California/USA)

508mm (333x)

Very finely split with just 333x, near equal light orange stars. Busy field, easy to make sketch to capture the orientation for short period project. 59 year period, near apastron, will tighten considerably by 2032.

KUI83

9^m.8

10^m.4

0.2"

240°

2012

Her

17^h37^m10.76^s / +27°53'47.10"

Mark McCarthy

Fremont (California/USA)

508mm (667x)

AC is an ordinary wide pair 2 delta mag ~10". AB is a hairline split with 533x, and an obvious well split with 667x. Light orange stars, ~1 delta mag. Short period, 24.1 years, nearly circular orbit so it will be fun to follow it around.

STF2199

8^m.0

8^m.6

2.0"

53°

2020

Dra

17^h38^m38.32^s / +55°45'34.90"

Mark McCarthy

Fremont (California/USA)

203mm (205x)

Light yellow stars, ~2" and ~1 delta mag. 1298 year period

STF2218

7^m.1

8^m.4

1.5"

310°

2016

Dra

17^h40^m18.07^s / +63°40'31.40"

Mark McCarthy

Fremont (California/USA)

203mm (205x)

~2 delta, split but quite close, with seeing. White A & yellow-white B. 2130 year period

★★

STF2241, psi 1 Dra, 31 Dra

4^m.6

5^m.6

29.6"

14°

2019

Dra

17^h41^m56.36^s / +72°08'55.80"

Christopher Hay Seeheim (Germany)	15x45	Stabilised binoculars, handheld. Easily split. A appears pearl white, B brick red. A very fine pair for 15x. Resolved in stabilised 10x42 but not so pleasantly. Psi1 Dra is a physical double with a period of roughly 10,000 years.
René Merting Drachhausen (Germany)	16x70	ein auffälliges Pärchen in einem wilden Sterngewimmel vieler heller Sterne, beide Komponenten sind knapp getrennt zu erkennen - Komponente B ist mindestens eine Größenklasse schwächer und strahlt nicht so schön reinweiß wie A
Christopher Hay Seeheim (Germany)	80mm (30x)	Widely split. A light yellow, B light blue.
Uwe Pilz Leipzig (Germany)	105mm (55x)	weiß-orange

HU1285

8^m.9

9^m.2

0.5"

211°

2016

Her

17^h43^m38.76^s / +22°36'43.20"

Frederik Wanink Itterbeck (Germany)	254mm (640x)	unsicher, sehr schwierig
Mark McCarthy Fremont (California/USA)	508mm (533x)	Hairline split at 445x, better split at 533x and 667x. White, slightly unequal. Physical with an 825-year period, it will make a very rapid periastron pass over the next couple of decades and appear on the opposite side, so it is worth watching

STF2205

9^m.4

9^m.6

0.9"

11°

2016

Her

17^h45^m41.03^s / +17°43'00.70"

Mark McCarthy

Fremont (California/USA)

508mm (667x)

Half delta mag light orange star about 1" separated (in this scope it is quite wide)

mu Her, 86 Her

STF2220

A-BC

3^m.5

9^m.8

35.5"

249°

2015

Her

17^h46^m27.51^s / +27°43'14.30"

AC7

10^m.2

10^m.7

0.6"

336°

2017

Robert Zebahl Leipzig (Germany)	120mm (86x)	STF2220 (A-BC): Easy, pretty wide, unequal pair. A appeared yellowish-orange, BC was barely visible with direct vision.
Mark McCarthy Fremont (California/USA)	203mm (333x)	STF2220 (A-BC): Pretty, bright canary yellow A and much fainter bluish B. Nice! (Missed AC 7 BC which are near equal 0.6")
Mark McCarthy Fremont (California/USA)	317mm (277x)	STF2220 (A-BC): Bright yellow with diffraction spikes and some haze around it (poor transparency). 4 delta mag small star on the edge of the haze, wide separation.
Mark McCarthy Fremont (California/USA)	317mm (553x)	STF2220 (A-BC): Bright white and 3-4 delta mag B, wide.
Mark McCarthy Fremont (California/USA)	508mm (533x)	AC7 (BC): Mu Her. Nice one to star with. STF 2220 A is a very bright light orange, and BC is widely separated blue, much fainter. I suspected B was also a pair at 333x, and could get a nice clean split with seeing at 533x, so I could tell an orientation and make a sketch (43-year period). Indeed it is a short period pair and I should be able to get at least a quarter turn out of it

★★★

HU1288

8^m.3

9^m.4

0.4"

163°

2016

Her

17^h47^m09.16^s / +15°02'13.80"

Mark McCarthy

Fremont (California/USA)

508mm (1067x)

Awesome! clean split, very clean star images. Split by half disk, half delta mag. very cool great catch! suspected at 667x, ramped up power to 1067x to split.

★

STT338

7^m.2

7^m.4

0.9"

168°

2018

Her

17^h51^m58.46^s / +15°19'34.90"

Uwe Pilz Leipzig (Germany)	120mm (250x)
Frederik Wanink Itterbeck (Germany)	254mm (640x)	getrennt
Mark McCarthy Fremont (California/USA)	317mm (553x)	Just split, a pair of bright near equal orange stars.
Mark McCarthy Fremont (California/USA)	508mm (667x)	Yellow-white very clean split stars seem more equal than what the data says

A235

8^m.4

9^m.3

0.3"

69°

2018

Her

17^h53^m18.60^s / +24°59'29.00"

Mark McCarthy

Fremont (California/USA)

508mm (533x)

Nice clean split, more than hairline, white stars, significant mag difference. With apodising mask. Currently at apastron, will make nearly half turn by 2040.

★★

STF2308

40/41 Dra

5^m.7

6^m.0

18.7"

232°

2019

Dra

18^h00^m09.07^s / +80°00'13.70"

5^m.7

8^m.3

225.3"

129°

2017

Robert Zebahl Leipzig (Germany)	8x44	2020-06-27: The pair AB split, but very tight with components of equal brightness. In acute angle far apart the component C was also visible.
Christopher Hay Seeheim (Germany)	15x45	AB: Clearly split, brighter component seems bluish. One of the finest doubles for 15x, hence my two-star rating. In 10x42 a difficult split at the limit.
René Merting Drachhausen (Germany)	16x70	ein schön eng stehendes Pärchen, die Himmelsrichtungen erschließen sich mir hier leider nicht, aber die Komponenten sind beide ähnlich hell und weiß - schöner Anblick im Fernglas
Christopher Hay Seeheim (Germany)	50mm (8x)	AB: An elongated figure-8 very close to splitting
Christopher Hay Seeheim (Germany)	80mm (30x)	AB: Very clearly split, dominates the 2.5° FOV, with interesting sprinkling of fainter stars throughout the field.
Robert Zebahl Leipzig (Germany)	102mm (28x)	Very nice, slightly uneven pair. Components appeared yellowish-white. Beautiful surroundings. On the sketch the components A, B and C are visible.
Uwe Pilz Leipzig (Germany)	105mm (100x)	AB: =40/41 Dra. Auffallend
Christopher Hay Seeheim (Germany)	140mm (75x)	AB: Wide apart, the pair absolutely dominates the field of view, with attractive sprinkling of fainter stars to the west. Very delicate colour contrast that was hard to grasp in 3-inch scope now becomes clear, component B (40 Dra) is bluish, component A (41 Dra) yellowish.

A1374

8^m.9

10^m.9

0.5"

213°

2019

Her

18^h00^m17.93^s / +21°53'47.50"

Mark McCarthy

Fremont (California/USA)

508mm (205x)

Very tough, the extraordinarily fine point of the B star appears with seeing. around 3 delta mag from light yellow A. Spectral class G0, yellow. Worth waiting for the seeing on this one. Physical with a 139.53-year period, it is slowly widening and will take another 30 years to reach apastron

STF2267

8^m.4

8^m.8

0.4"

281°

2018

Her

18^h01^m41.17^s / +40°10'41.90"

Frederik Wanink

Itterbeck (Germany)

254mm (640x)

nicht als DS gesehen

STF2262, tau Oph

5^m.3

5^m.9

1.5"

290°

2019

Oph

18^h03^m04.91^s / -08°10'48.90"

Frederik Wanink

Itterbeck (Germany)

254mm (240x)

getrennt

../projects/double-stars/frederik-wanink/sketches/STF2262.jpg

70 Oph, P Oph, STF2272

4^m.2

6^m.2

6.6"

122°

2019

Oph

18^h05^m27.37^s / +02°29'59.30"

Uwe Pilz Leipzig (Germany)	16x70	nicht einfach; der helle ist gelb
Christopher Hay Seeheim (Germany)	25x80	Clean split, component A appears yellowish. 70 Oph is the left nostril of the bull in the old constellation Taurus Poniatowski (Poniatowski’s Bull). On the connections to 67, 68 and 73 Oph see the entry on 67 Oph.
René Merting Drachhausen (Germany)	100mm (64x)	bei 32x wirkt der Stern nicht rund, sondern ein wenig nach SO verschmiert - bei 64x dann eindeutig ein knapp getrenntes schön anzusehendes Pärchen - Komponente A hell-gelb, B orange-gelb
Jörg S. Schlimmer Germany	127mm (136x)	easy to split
Sarah Gebauer Germany	150mm (85x)	ein ganz leicht goldener Farbeindruck des Sternpaares, die Sterne stehen recht dicht beisammen und sind dennoch schön getrennt
Robert Zebahl Leipzig (Germany)	200mm (80x)	Conditions in the target region: SQM-L 20.1 Well split at 80x. Brighter component appeared white, fainter one slightly orange.

Berthold Fuchs

Wiesbaden (Germany)

130mm

difficult DS

../projects/double-stars/berthold-fuchs/photographs/70%20Ophiuchi.png

STT341

7^m.4

8^m.8

0.1"

86°

2019

Her

18^h05^m49.72^s / +21°26'45.60"

AB-C

7^m.2

10^m.6

28.2"

171°

2015

AB-D

7^m.2

10^m.5

39.5"

99°

2009

AB-E

7^m.2

10^m.2

66.5"

38°

2018

AB-F

7^m.2

11^m.5

111.6"

357°

2009

AB-G

7^m.2

7^m.6

132.5"

239°

2018

René Merting

Drachhausen (Germany)

100mm (32x)

AB-C: bei 32x ist Komponente C weit getrennt südlich von AB als Hauch von einem Stern erkennbar
AB-D: bei 32x ist Komponente D im Osten von AB ist ähnlich schwach erkennbar wie C im Süden - D ist etwas weiter weg als C
AB-E: bei 32x ist Komponente E im NO von AB ähnlich schwach erkennbar wie C im Süden und D im Osten - Entfernung zu A doppelt so weit wie AB-C
AB-F: bei 64x ist F im Norden von AB in vierfacher Entfernung AB-C erkennbar - im Grunde spiralen die vier schwachen Komponenten von Süden kommend von Osten nach Norden aus

★

AC15, 99 Her

5^m.1

9^m.0

1.4"

331°

2018

Her

18^h07^m01.61^s / +30°33'42.70"

Mark McCarthy

Fremont (California/USA)

203mm (667x)

99 Her.Very nice. B star resolves just outside first diffraction ring when that ring has faded with good seeing, a very fine faint point. large delta mag. There are many other pairings in this system, including 0.2" for the A star]

STT524

7^m.9

8^m.9

0.5"

207°

2018

Her

18^h07^m29.52^s / +19°39'59.10"

Mark McCarthy

Fremont (California/USA)

508mm (533x)

Suspected hairline with 333x, nice clean split at 533x, white stars, significant magnitude difference, ~0.5". 686 year period

COU812

10^m.8

0.7"

265°

2016

Her

18^h09^m09.93^s / +31°29'10.50"

Mark McCarthy

Fremont (California/USA)

203mm (667x)

Elongation, marginal notch, but a bit too hazy to make a good observation

STF2281, 73 Oph

6^m.0

7^m.5

0.8"

283°

2019

Oph

18^h09^m33.86^s / +03°59'35.80"

Frederik Wanink

Itterbeck (Germany)

254mm (640x)

als 8 zu sehen, schwierig

../projects/double-stars/frederik-wanink/sketches/73Oph.jpg

★★

HU674

7^m.7

8^m.6

0.7"

214°

2018

Her

18^h09^m40.64^s / +50°24'07.40"

Frederik Wanink Itterbeck (Germany)	254mm (640x)	getrennt, ähnlich hell
Mark McCarthy Fremont (California/USA)	508mm (333x)	Split with seeing at 333x, near equal white.

STF2289

6^m.7

7^m.2

1.2"

218°

2019

Her

18^h10^m08.69^s / +16°28'35.00"

Mark McCarthy Fremont (California/USA)	203mm (333x)	Just split in 20" at 205x, but flaring. 333x had messy diffraction. 8" mask at 333x gave clean disks, split, ~0.7". Dull yellow and yellow-red colors.
Frederik Wanink Itterbeck (Germany)	254mm (640x)	Hauptstern gelb, Begleiter scheint bläulich

COU1006

9^m.2

11^m.3

0.5"

337°

2016

Her

18^h12^m58.00^s / +33°17'53.90"

Mark McCarthy

Fremont (California/USA)

508mm (667x)

B is very much fainter and can only be seen when A is perfectly still and round, with seeing. Fairly well separated about 0.5", can tell PA with drift. Physical with 119.2-year period, it is coming off periastron and slowly widening

STT353, phi Dra

4^m.5

5^m.9

0.5"

266°

2011

Dra

18^h20^m45.44^s / +71°20'15.80"

Frederik Wanink

Itterbeck (Germany)

254mm (640x)

nicht als DS gesehen

Frederik Wanink

Itterbeck (Germany)

254mm

../projects/double-stars/frederik-wanink/photographs/STT%20353%20AB.jpg

BU640

7^m.0

12^m.0

0.7"

322°

2008

Her

18^h20^m49.23^s / +27°31'48.30"

Mark McCarthy

Fremont (California/USA)

178mm (533x)

Very much fainter B seen with averted vision and foveal coaxing only, can only hold it briefly. Physical with a 951.7127-year period (to be exact), it is now making a very fast turn around apastron -- though I think the orbital solution is predicting an incorrect position (too close to apastron at this moment) -- unfortunately I did not record the PA so I can't tell if it's on the west or east side of apastron. Will need to re-observe this, since I don't think I'd see 0.2" at 533x (likely around >0.5" given the delta mag)

★

HU581

8^m.8

9^m.4

0.4"

122°

2016

Her

18^h22^m54.84^s / +14°58'11.00"

Mark McCarthy

Fremont (California/USA)

508mm (1067x)

Snowman at 533x & 667x, clean split at 1067x & apodising mask, one delta mag. Amazing. Coalesces into two points, can easily tell orientation & magnitude difference for sketch. At apastron, it is on a nearly edge on orientation, will close rapidly within the next ten years to be too close for me to detect.

HO83

10^m.1

10^m.4

0.8"

115°

2016

Her

18^h23^m20.34^s / +27°31'24.10"

Mark McCarthy

Fremont (California/USA)

178mm (445x)

Pretty difficult, B appears with averted vision only and fades with direct. Much fainter, about 1". Physical with a 1699.9512-year period, it will soon make a turn toward periastron and tighten over the next few decades. Discovered in 1883 at 0.3"

★

STF2323, 39 Dra

5^m.1

8^m.1

3.6"

348°

2020

Dra

18^h23^m54.65^s / +58°48'02.10"

5^m.1

8^m.0

88.9"

20°

2020

Robert Zebahl Leipzig (Germany)	55mm (27x)	AC: Pretty wide, unequal pair. Die brighter A component appeared white.
Robert Zebahl Leipzig (Germany)	55mm (71x)	AB: Very nice. The B component seemed to be comparable faint as the C component.
Mark McCarthy Fremont (California/USA)	203mm (205x)	AB: 39 Dra. Brilliant white A and slightly ruddy B, ~3 delta mag, ~4" sep. 3962.5 year period.

★

STF2315

6^m.6

7^m.8

0.6"

117°

2018

Her

18^h24^m58.46^s / +27°23'41.30"

Frederik Wanink Itterbeck (Germany)	254mm (640x)	als 8 zu sehen
Mark McCarthy Fremont (California/USA)	317mm (277x)	! Hairline split @ 553x near equal mag. Suspected elongation at 277x.:
Mark McCarthy Fremont (California/USA)	508mm (533x)	Barely split with seeing, resolves to two disks, more than hairline but almost 2 delta mag, very tough, need perfect seeing. 2094 year period

STT351 & HU66

HU66

7^m.9

8^m.4

0.2"

197°

2016

Dra

18^h25^m18.20^s / +48°45'42.50"

STT351

7^m.9

8^m.2

0.8"

26°

2019

HU66

8^m.4

8^m.2

0.8"

26°

2019

Mark McCarthy Fremont (California/USA)	203mm (305x)	STT351 (AC): Split, better with seeing, light orange stars, significant mag difference. Did not notice HU 66 AB, 7.9/8.4 0.1" or HU 66 BC, 8.40/8.25 0.9 -- need to go back to this one!
Frederik Wanink Itterbeck (Germany)	254mm (640x)	HU66 (BC): getrennt
Mark McCarthy Fremont (California/USA)	317mm (553x)	HU66 (BC): Very fine near equal pair, yellowish A and blue-white B. ~1" or less.
Mark McCarthy Fremont (California/USA)	508mm (333x)	STT351 (AC): Orange stars, noticeable magnitude difference ~0.5, separated just less than ~1". What's curious is the AB pair is HU 66 AB listed as 7.90/8.40 0.1" currently, with HU 66 BC as 8.40/8.25 0.9". So my question is, if AC is physical, and if BC are physical too, why is AC uncertain? It would seem they should all be sharing orbits? Perhaps it just cries out for additional measures -- AB is grade 4 and BC is grade 5, so they are confident of physicality but there's not enough data to nail it down.

HU322

7^m.7

8^m.9

0.2"

92°

2019

Her

18^h33^m45.62^s / +17°43'55.90"

Mark McCarthy

Fremont (California/USA)

508mm (889x)

Very subtle notched elongation, PA on an E-W line but a little cocked from WAK 21. Component of STF 2339 AB-CD

★★

STT359

6^m.3

6^m.6

0.7"

3°

2019

Her

18^h35^m30.40^s / +23°36'19.90"

Robert Zebahl Leipzig (Germany)	102mm (160x)	2020-11-10: Clearly elongated with slight notching and little difference in brightness. I estimated the position angle to 0°.
Uwe Pilz Leipzig (Germany)	105mm (198x)	leicht eingekerbt, Abstand 0“75
Uwe Pilz Leipzig (Germany)	120mm (250x)
Mark McCarthy Fremont (California/USA)	152mm (175x)	Light orange near equal stars, notched elongation, overlapping disks. Physical with a 219-year period, at apastron now
Mark McCarthy Fremont (California/USA)	203mm (667x)	Kissing 8" 333x, hairline split 667x. Near equal white A and bluish white B.
Frederik Wanink Itterbeck (Germany)	254mm (640x)	getrennt
Mark McCarthy Fremont (California/USA)	317mm (553x)	Nice! ~0.8" equal yellow-orange stars.
Uwe Pilz Leipzig (Germany)	320mm (388x)	ein sehr ruhiger Abend gestattete die Nutzung von 12 Zoll
Mark McCarthy Fremont (California/USA)	508mm (333x)	Light yellow near equal split, very close. 219 year period

★★

STT358

6^m.9

7^m.1

1.7"

146°

2019

Her

18^h35^m53.22^s / +16°58'32.50"

Uwe Pilz Leipzig (Germany)	105mm (110x)	fast gleich hell, deutlich trennbar
Mark McCarthy Fremont (California/USA)	203mm (333x)	Pretty, near equal white, perfect disks.
Mark McCarthy Fremont (California/USA)	508mm (205x)	Yellow-white stars, half delta mag, well split. 380 year period

STT363

7^m.5

8^m.1

0.6"

336°

2018

Dra

18^h37^m23.92^s / +77°41'12.40"

Frederik Wanink

Itterbeck (Germany)

254mm (640x)

als 8 zu sehen

Frederik Wanink

Itterbeck (Germany)

254mm

../projects/double-stars/frederik-wanink/photographs/STT%20363.jpg

STF2367

7^m.7

8^m.0

0.4"

74°

2019

Lyr

18^h41^m16.36^s / +30°17'40.90"

AB-C

7^m.0

8^m.8

14.1"

192°

2019

AB-D

7^m.0

12^m.0

21.9"

84°

2007

AB-E

7^m.0

11^m.0

151.7"

341°

2002

René Merting Drachhausen (Germany)	100mm (32x)	AB-C: bei 32x einfach zu trennen - A-Komponente leicht gelblich, Komponente C südlich ist deutlich schwächer und strahlt zinnober
Mark McCarthy Fremont (California/USA)	178mm (205x)	AB-C: Light yellow-orange A and light blue B, >1 delta mag, very wide. (Need to return to this one, AB is a short 94-year period 0.45", nearing apastron.) WDS calls AB-C physical on the similar proper motions, unfortunately there is no parallax data for A
Frederik Wanink Itterbeck (Germany)	254mm (640x)	AB: nicht als DS gesehen

STF2398

9^m.1

10^m.0

11.4"

181°

2020

Dra

18^h42^m46.69^s / +59°37'49.40"

Mark McCarthy

Fremont (California/USA)

203mm (205x)

Very light orange stars, ~1 delta mag, wide. 408 year period

★★★

epsilon Lyr

STF2382, 4 Lyr, epsilon 1 Lyr

5^m.2

6^m.1

2.2"

345°

2020

Lyr

18^h44^m20.34^s / +39°40'12.40"

STFA37

AB-CD

4^m.7

4^m.6

209.5"

172°

2016

STFA37

5^m.2

10^m.1

149.5"

137°

2015

STF2383, 5 Lyr, epsilon 2 Lyr

5^m.2

5^m.4

2.4"

75°

2020

Christopher Hay Seeheim (Germany)	naked eye	STFA37 (AB-CD): While waiting for Comet Neowise at 3 in the morning in July 2020 surprised myself with my first naked-eye separation of Alpha1 und Alpha2 Capricornis (observing site at 50° northern latitude, Alpha1/2 passing through meridian). Encouraged by this, I lay down and had a close look at Epsilon Lyrae, without really expecting to be able to split it naked-eye, having never succeeded previously. At first Epsilon Lyrae appeared as a very short dash of light. Then the dash resolved into two pinpoints. After 15 years in the hobby and at age 60, at last got Eps Lyr split! No precise prior PA knowledge. After memorising PA as seen naked-eye carefully, confirmed it with binoculars. Eps Lyr is the third-easiest physical double in the (northern hemisphere) summer sky for the naked eye, after Zeta UMa (much easier) und Alpha Lib (marginally easier).
Christopher Hay Seeheim (Germany)	2x54	STFA37 (AB-CD): Clean split. Actually more pleasant than in 4x10 binoculars, presumably due to more steady handheld view.
Robert Zebahl Leipzig (Germany)	55mm (59x)	STF2382 (AB): At 42x slightly elongated, at 59x elongated and obviously notched.
Robert Zebahl Leipzig (Germany)	55mm (59x)	STF2383 (CD): At 42x clearly elongated, but without any visible notch. At 59x split with touching diffraction disks.
Robert Zebahl Leipzig (Germany)	70mm (57x)	STF2382 (AB): Obviously seen as figure '8'.
Robert Zebahl Leipzig (Germany)	70mm (57x)	STF2383 (CD): Split, but extremely tight with almost touching diffraction disks.
René Merting Drachhausen (Germany)	76mm (95x)	AB-CD: bei 29x schön getrennt erkennbar, ohne dass sich AB und CD schon trennen lassen AB: bei 57x leicht länglich mit kleiner Einschnürung - bei 95x schön eng getrennt, B nördlich wirkt etwas schwächer- bei 127x wunderschön, das Sternpaar hat zwei Beugungsscheibchen, die wie ein Heiligenschein um die beiden Sterne stehen CD: bei 57x eine 8 - bei 95x ein schön eng getrenntes Pärchen gleichheller Sterne - bei 127x wunderschön, das Sternpaar hat zwei Beugungsscheibchen, die wie ein Heiligenschein um die beiden Sterne stehen EF und I: bei 127x sind alle drei Sterne (I 10.1 mag / E 12.3 mag / F 12.7 mag) erkennbar
René Merting Drachhausen (Germany)	100mm (107x)	AB: bei 64x ist das Sternpaar mit leichter Einschnürung und Nord-Süd-Ausdehnung erkennbar - beide Sterne stehen minimal enger zusammen als das südlichere Paar CD - bei 107x knappe Trennung, Komponente B nördlich ist mindestens eine halbe Größenklasse schwächer als A CD: bei 64x als 8 mit Ost-West-Ausdehnung erkennbar - bei 107x knapp getrennt, beide Komponenten sind etwa gleich hell
Sarah Gebauer Germany	100mm (136x)	ein Test mit dem neuen Refraktor, um einen Vergleich zum 6''-Newton zu ziehen: bei 136x schon astrein getrennt, natürlich ziemlich eng und ganz fein getrennt, aber dennoch ein überraschend positives Ergebnis
Robert Zebahl Leipzig (Germany)	102mm (125x)	Stunning view of the components A-D and I!
Uwe Pilz Leipzig (Germany)	105mm (26x)	bei 22x nicht trennbar
Jörg S. Schlimmer Germany	127mm (203x)	easy to split
Sarah Gebauer Germany	150mm (250x)	August 2019 zum ersten Mal die nah beieinanderstehenden Komponenten sauber getrennt, ein grandioser Doppel-Doppel-Anblick
Winfried Kräling Marburg (Germany)	152mm (175x)
René Merting Drachhausen (Germany)	320mm (144x)	bei 144x sind die Komponenten von AB und CD gerade so getrennt voneinander erkennbar, sie tanzen wie wild miteinander - mit Arperturmaske und Abblendung auf 120 mm zeigen die vier nun deutlich schwächeren Sterne schöne Beugungsscheibchen und sind besser getrennt voneinander sichtbar
Uwe Pilz Leipzig (Germany)	320mm (200x)	7 Komponenten!! A-B-C-D-E-F-I

Berthold Fuchs

Wiesbaden (Germany)

130mm

Double-Double

../projects/double-stars/berthold-fuchs/photographs/epsilon%20Lyrae.png

HU937

8^m.8

9^m.9

1.0"

333°

2016

Dra

18^h46^m13.38^s / +64°11'44.40"

Mark McCarthy

Fremont (California/USA)

508mm (333x)

Hairline split at 205x, more definite split with 333x, ~1 delta mag. A is yellow-white, B is a deeper yellow-orange. 225.53 year period

HU1191

8^m.7

9^m.4

0.2"

338°

2016

Lyr

18^h46^m34.62^s / +38°21'04.00"

Mark McCarthy

Fremont (California/USA)

508mm (1067x)

V595 Lyr. Very tough! In unsettled seeing it is an elongation or lopsided at all powers. However at best moments it tightens enough to show a very subtle notch & also different brightness and color, A being light orange-yellow, and ~1 delta mag B a deeper orange. Discovered in 1902 at 0.2, it has only a 14.64 year period, it will make a rapid circuit to the other side by 2026 (though only 0.1"), and "widen" to 0.2" again by 2030. Should be fun to observe!

STF2402

8^m.9

9^m.3

1.5"

208°

2016

Aql

18^h49^m44.14^s / +10°40'35.40"

Mark McCarthy

Fremont (California/USA)

203mm (667x)

Lovely near equal, tight but well split. Forms a perfect triangle with two other stars

★

BU137

8^m.7

9^m.0

1.3"

203°

2020

Lyr

18^h53^m57.56^s / +37°22'49.70"

Frederik Wanink Itterbeck (Germany)	254mm (640x)
Mark McCarthy Fremont (California/USA)	317mm (553x)	Fine near equal light orange, ~2". Rich finder field. In Steph 1 open cluster.
Mark McCarthy Fremont (California/USA)	508mm (667x)	Nice bright white near equal stars, 1.5", in a two plus one system with much fainter farther C. (AC 12th mag 23.6")

A258

8^m.9

9^m.9

0.3"

228°

2018

Lyr

18^h54^m59.91^s / +30°52'45.50"

Mark McCarthy

Fremont (California/USA)

508mm (667x)

Very tough. I get elongation at 553x, and more clear elongation at 667x, but no split, not even notching, more like an unevenly illuminated rod. Seeing not support higher power.

BU648

5^m.3

8^m.0

1.2"

232°

2020

Lyr

18^h57^m01.61^s / +32°54'04.60"

Mark McCarthy Fremont (California/USA)	152mm (285x)	Orange A and a just split, very small, very faint B, seen only with 285x --175x suspected, 456x image quality not good. Short period pair, it will make a half revolution by 2045
Mark McCarthy Fremont (California/USA)	317mm (553x)	277x an orange not quite round disk, suspected a close pair. At 553x it splits with seeing, 0.8", 3 delta mag, in diffraction.

STF2438

7^m.0

7^m.4

0.8"

357°

2019

Dra

18^h57^m28.47^s / +58°13'30.00"

Frederik Wanink Itterbeck (Germany)	254mm (640x)	leicht; beide gleich hell
Mark McCarthy Fremont (California/USA)	508mm (333x)	Hairline split, white stars, near equal. 261.6 year period, look how fast it will move in the years 2150-2160!

AG366

8^m.5

8^m.7

1.4"

183°

2019

Lyr

18^h58^m03.46^s / +47°11'30.10"

Mark McCarthy

Fremont (California/USA)

508mm (205x)

Near equal yellow-white easy split

HU332

9^m.7

9^m.6

0.5"

267°

2016

Vul

18^h59^m03.72^s / +22°30'03.20"

Mark McCarthy

Fremont (California/USA)

508mm (533x)

Beautiful close split, a little more than hairline, light orange stars near equal

★

STF2437

8^m.4

8^m.8

0.6"

1°

2019

Sge

19^h01^m53.16^s / +19°10'11.70"

Mark McCarthy Fremont (California/USA)	178mm (333x)	Light orange, snowman only. Physical with a 804.6-year period
Mark McCarthy Fremont (California/USA)	317mm (553x)	Small faint, notched peanut when seeing stills. Orange.

AG227

10^m.7

11^m.2

7.1"

31°

2015

Lyr

19^h05^m22.05^s / +38°03'20.60"

Mark McCarthy

Fremont (California/USA)

508mm (667x)

This is the brighter pair of the double-double pair mentioned in last entry (ALI 614). White stars, brilliant, wide separation

HU940

9^m.2

9^m.8

0.4"

187°

2016

Lyr

19^h05^m30.86^s / +33°52'21.50"

Mark McCarthy

Fremont (California/USA)

508mm (667x)

Hairline at 445x, split with 667x, slightly unequal white stars. Physical with 111.6-year period, it will tighten in the next couple of decades

STF2454

8^m.3

9^m.7

1.3"

291°

2016

Lyr

19^h06^m09.37^s / +30°26'18.80"

Mark McCarthy Fremont (California/USA)	317mm (553x)	Fine yellowish pair, ~1.5"
Mark McCarthy Fremont (California/USA)	508mm (667x)	Nice well split 2 delta mag, white A reddish B. (DRD 2 AC is 13.50 mag and 31.3")

HEI568, 18 Aql

5^m.4

6^m.4

0.3"

248°

2019

Aql

19^h06^m58.60^s / +11°04'16.70"

Mark McCarthy

Fremont (California/USA)

508mm (410x)

18 Aql. The A star is elongated / smeared but 410x does not resolve, seeing not good enough.

STT369

7^m.8

7^m.9

0.7"

5°

2018

Dra

19^h07^m06.37^s / +72°04'26.60"

Frederik Wanink

Itterbeck (Germany)

254mm (640x)

zeitweilig gut erkennbar

../projects/double-stars/frederik-wanink/sketches/STT369.jpg

SE2

8^m.3

9^m.4

0.1"

21°

2010

Lyr

19^h11^m07.99^s / +38°46'52.40"

Mark McCarthy

Fremont (California/USA)

508mm (1334x)

This is a component of STF2481 which I viewed through the 6-inch recently. I see a very slight elongation to B all powers, but no resolution or notching. Physical with a 62.79-year period, it will thankfully widen and be a far easier target (at 0.3") by 2030

★

STF2486

6^m.5

6^m.7

7.2"

204°

2020

Cyg

19^h12^m05.03^s / +49°51'20.70"

René Merting Drachhausen (Germany)	15x56	eine Ameise mit Nordost-Südwestausdehnung - Einschnürung nur leicht
Robert Zebahl Leipzig (Germany)	16x70	2020-07-03: Fine split, but very tight with equally bright components.
Robert Zebahl Leipzig (Germany)	70mm (22x)	At 22x barely split with a slight difference in brightness. At 44x the primary looked orange. I could not determine the color of the companion.
Mark McCarthy Fremont (California/USA)	317mm (553x)	Near equal yellow pair.

★

BU139 & STTA177, V338 Sge

BU139

7^m.1

8^m.0

0.6"

136°

2017

Sge

19^h12^m34.45^s / +16°50'47.20"

STTA177

7^m.1

8^m.0

98.4"

276°

2017

BU139

7^m.1

11^m.2

28.8"

101°

2015

BU139

8^m.0

11^m.2

138.9"

269°

2015

Mark McCarthy Fremont (California/USA)	80mm (13x)	STTA177 (AC): Near equal wide pair split in finder
Mark McCarthy Fremont (California/USA)	152mm (456x)	BU139 (AB): Very subtle notched unequal elongation at all powers. Physical with a 587-year period, currently coming of apastron, it will continue to tighten. Component of STT 177. Burnham discovered with his 6-inch in at 0.5", about what it is now, an astounding catch
Frederik Wanink Itterbeck (Germany)	254mm (640x)	BU139 (AB): getrennt, schwierig, 0,6"?
Mark McCarthy Fremont (California/USA)	317mm (553x)	STTA177 (AC): Very wide orange-yellow and blue, ~2-3 delta mag.

STF2484

7^m.9

9^m.5

2.1"

242°

2017

Sge

19^h14^m15.66^s / +19°03'50.30"

René Merting Drachhausen (Germany)	100mm (142x)	bis 142x probiert, keine Chance, Komponente B zeigt sich nicht
Mark McCarthy Fremont (California/USA)	178mm (205x)	Cream white A and yellow B, 2" separation, 2 delta mag, very pretty. Physical with a 1500-year period
Mark McCarthy Fremont (California/USA)	317mm (553x)	Very close, ~2", orange, 1.5 delta mag.

BU1129

7^m.7

7^m.8

0.3"

344°

2016

Cyg

19^h21^m36.09^s / +52°22'34.90"

Mark McCarthy

Fremont (California/USA)

508mm (889x)

Light orange stars, obviously not single at 445x, and the disks separated as I powered up. Less than 1 delta mag, the best view with 889x, which showed a constant hairline split even with wavering seeing, PA NNW. A really nice pair. Spectral class A8III (white). 121.7-year period, currently 0.328" separated, it is approaching apastron now and will hang there until the 2050s. Burnham discovered in 1889 on the Lick 36-inch at 0.3" and noted "If [the proper motion in Ast. Gess. Catalogue]...is substantially correct, this is a physical system."

STF2525

8^m.2

8^m.4

2.3"

290°

2020

Vul

19^h26^m33.71^s / +27°19'21.90"

Robert Zebahl Leipzig (Germany)	152mm (100x)	2020-06-24: At 49x slightly elongated, at 69x just separated with visible difference in brightness. At 100x nice view with clear separation and slight difference in brightness, but no visible colors.
Mark McCarthy Fremont (California/USA)	152mm (175x)	Close near equal white stars. Physical with 289-year period
Mark McCarthy Fremont (California/USA)	508mm (205x)	Near equal yellow-white stars, wide. An amazingly precise 882.894 year period. I will not notice the change

MCA55, bet 1 Cyg

Aa-Ac

3^m.4

5^m.2

0.3"

46°

2021

Cyg

19^h30^m43.29^s / +27°57'34.90"

Mark McCarthy

Fremont (California/USA)

508mm (445x)

Alberio A. Using all powers at both 20-inch and 7-inch, A is consistently out of round with the weaker end in the southern direction. Alberio B remains relatively round in the diffraction dance. Currently 0.365", it is widening to apastron by 2035 and might even be splitable by then

STF2536

8^m.4

11^m.4

1.8"

120°

2018

Sge

19^h31^m37.80^s / +17°46'58.60"

Mark McCarthy

Fremont (California/USA)

508mm (205x)

Blue-white A and much fainter ~3 delta B, split close, dull orange color. Very fine. Physical with 672.5 year period

STT375

7^m.7

8^m.9

0.7"

183°

2018

Sge

19^h34^m37.45^s / +18°07'41.20"

Mark McCarthy Fremont (California/USA)	317mm (553x)	Sense an elongation or rod, marginal.
Mark McCarthy Fremont (California/USA)	508mm (533x)	Snowman at 205x, 333x, split with 533x, >1 delta mag, ~0.5". A is orange-yellow and B is blue-white. Physical with 682 year period, just coming apastron now.

★★

STFA46, 16 Cyg

6^m.0

6^m.2

39.7"

133°

2020

Cyg

19^h41^m49.09^s / +50°31'31.60"

Christopher Hay Seeheim (Germany)	3x63	Self-built binoculars, hence the unusual specification. Made of top-quality teleconverters, apochromatic and sharp to the edge. With naked eye under good suburban sky 16 Cyg is just seen. In the 3x binoculars the double is split into two finest points of light in good moments despite the low magnification. A physical pair according to Stelledoppie. Two-star rating awarded because this is a true physical pair that can be split with the smallest binoculars and reveals increasingly more with growing binocular size (brightness disctinction between A and B in 7x50, colour distinction in 15x45).
Christopher Hay Seeheim (Germany)	7x50	Finely split, A-component appears very slightly brighter than B-component. A very pleasing binocular pair.
Christopher Hay Seeheim (Germany)	15x45	Wide split, very strong visual presence dominating 4.5° FOV. A-component very pale orange, B-component equally pale blue.
Robert Zebahl Leipzig (Germany)	16x70	2021-06-01: Very striking, bright at moderate separation and small difference in brightness. White-yellowish & white.
René Merting Drachhausen (Germany)	18x70	zwei ordentlich getrennte fast gleich helle Sterne - beide Komponenten sind reinweiß und die hellsten Sterne im unmittelbaren Umfeld - auffällig
Christopher Hay Seeheim (Germany)	44x100	Extremely strong pair in 1.9° FOV. Northern component marginally brighter and with slightest touch of yellow.
Sarah Gebauer Germany	100mm (80x)	der Doppelstern springt mich regelrecht an bei der Suche nach dem Blinking PN, es sind zwei ganz durchdringende, gleich helle Sternpunkte, die zwar schon einem sternreichen Umfeld stehen, aber dennoch deutlich heller hervortreten; südlich davon befindet sich rein optisch betrachtet eine abgeschwächte Kopie davon
Mark McCarthy Fremont (California/USA)	317mm (553x)	16 Cyg: Wide equal orange-yellow, also split in 80mm finder

KUI94

6^m.5

7^m.8

0.5"

158°

2014

Cyg

19^h41^m57.63^s / +40°15'14.60"

Frederik Wanink

Itterbeck (Germany)

254mm (640x)

unsicher, 8förmig

Frederik Wanink

Itterbeck (Germany)

254mm

../projects/double-stars/frederik-wanink/photographs/KUI%2094.jpg

STT383

7^m.0

8^m.3

0.8"

15°

2014

Cyg

19^h42^m56.26^s / +40°43'18.30"

7^m.0

11^m.6

45.2"

99°

2002

7^m.0

12^m.4

68.1"

43°

2002

Robert Zebahl Leipzig (Germany)	152mm (240x)	AB: 2022-08-07: Under these average conditions the double star is well visible as such. The fainter companion appears as a washed out star close to the primary component. In quiet moments the overlapping diffraction disks are well visible.
Frederik Wanink Itterbeck (Germany)	254mm (640x)	AB: getrennt

Frederik Wanink

Itterbeck (Germany)

254mm

../projects/double-stars/frederik-wanink/photographs/STT%20383%20AB.jpg

★

STF2579, delta Cyg, 18 Cyg

2^m.9

6^m.3

2.7"

213°

2020

Cyg

19^h44^m58.44^s / +45°07'50.50"

Robert Zebahl Leipzig (Germany)	70mm (200x)	2019-07-28: At 100x only indicated. At 200x the much fainter companion is visible as a slightly elongated brightening on the first diffraction ring.
Uwe Pilz Leipzig (Germany)	105mm (288x)	blauweiß
Robert Zebahl Leipzig (Germany)	152mm (133x)	2022-09-21: At 92x clearly separated, but still pretty tight. Primary component slightly yellowish with much fainter companion. At 133x easy to separate. The faint companion appears orange-brownish.
Mark McCarthy Fremont (California/USA)	317mm (553x)	Very bright white with ruddy B, ~4", 4 delta mag. Nice!

17 Cyg

STF2580

5^m.1

9^m.2

25.9"

68°

2020

Cyg

19^h46^m25.60^s / +33°43'39.30"

STF2580

5^m.1

9^m.4

106.3"

122°

2020

WNO56

5^m.1

8^m.5

792.0"

235°

2002

STF2580

9^m.2

8^m.6

817.6"

236°

2010

STF2576

8^m.5

8^m.6

3.2"

155°

2020

René Merting Drachhausen (Germany)	100mm (20x)	AB: bei 20x locker getrennt - Komponente A satt gelb, B wegen des großen Helligkeitsunterschiedes gräulich-bräunlich
Uwe Pilz Leipzig (Germany)	120mm (140x)
Robert Zebahl Leipzig (Germany)	152mm (92x)	2021-07-24: At 30x the components A, B & C are easily visible, whereby A & B are still quite close together. The bright component A appears in a pale yellow. At 92x also the pair FG is separated easily and looks less belonging to the system because of the wide separation to the other components. All in all it is worth observing.
Winfried Kräling Marburg (Germany)	152mm (175x)	A, B & C
Mark McCarthy Fremont (California/USA)	317mm (277x)	AB: 17 Cyg: Yellow and slightly red, well separated, 1 delta mag. (This is an amazingly complex system with 11 stars in all sorts of combinations. Why not just call it an open cluster?)

★

STT387

7^m.1

7^m.9

0.5"

94°

2020

Cyg

19^h48^m43.81^s / +35°18'41.30"

Frederik Wanink Itterbeck (Germany)	254mm (640x)	zeitweise als 8 zu sehen
Mark McCarthy Fremont (California/USA)	317mm (277x)	Red, very close pair? Seeing not supporting higher magnification. Marginal.
Mark McCarthy Fremont (California/USA)	317mm (553x)	Overlapping disks, to a nearly hairline split with seeing. Half delta mag.

Frederik Wanink

Itterbeck (Germany)

254mm

../projects/double-stars/frederik-wanink/photographs/STT%20387.jpg

★

DJU4, 13 Vul

4^m.6

7^m.4

1.5"

248°

2020

Vul

19^h53^m27.69^s / +24°04'46.60"

Mark McCarthy Fremont (California/USA)	152mm (285x)	Gorgeous! Bright A and 3 delta mag B appears as a fine point just beyond A's diffraction. Seen at 175x, best at 285x. Physical with a 615-year period, at apastron
Frederik Wanink Itterbeck (Germany)	254mm (640x)	schwierig wegen Helligkeitsunterschied

STF2596

7^m.3

8^m.7

2.1"

297°

2016

Aql

19^h54^m01.95^s / +15°17'31.70"

René Merting Drachhausen (Germany)	100mm (107x)	bei 107x ist Komponente B knapp abgesetzt nordwestlich von der A-Komponente sichtbar, knappe Trennung - Helligkeitsunterschied gut 1.5 Größenklassen
Mark McCarthy Fremont (California/USA)	152mm (175x)	Light yellow A and light blue B, nicely separated, very pretty. Physical with a 2971-year period
Mark McCarthy Fremont (California/USA)	203mm (533x)	Orange pair with 2 delta mag companion, about 2", well split.

HO581

8^m.0

8^m.7

0.1"

230°

2012

Cyg

19^h54^m58.40^s / +41°52'17.60"

Mark McCarthy

Fremont (California/USA)

508mm (667x)

Very subtly notched elongation at best, light orange stars. 25.63 year period, near apastron in a nearly circular orbit, it will widen slightly in the next 5 years and still be a detectable 0.2" in 2035.

STT392 & STF2607

STT392

6^m.6

8^m.4

0.1"

184°

1996

Cyg

19^h57^m56.12^s / +42°15'38.90"

STF2607

AB-C

6^m.6

9^m.1

3.0"

289°

2012

René Merting Drachhausen (Germany)	100mm (107x)	STF2607 (AB-C): bei 107x ist C knapp westlich von AB zu erkennen, in guten Momenten sind die Komponenten getrennt sichtbar - trotz des großen Helligkeitsunterschiedes von schätzungsweise 1,5 bis 2 Größenklassen wirkt C ggü. AB auch erstaunlich weißlich
Robert Zebahl Leipzig (Germany)	152mm (92x)	STF2607 (AB-C): 2022-08-07: Clearly separated at 92x, but relatively close pair with noticeable difference in brightness. AB appears yellowish, C brownish. At 171x easy to separate with slightly different color impression: AB appears yellowish, partly light orange, C rather gray-bluish.
Mark McCarthy Fremont (California/USA)	152mm (175x)	STF2607 (AB-C): Pretty light yellow-white A and reddish B, 2 delta mag, around 4". Nice. AB is STT 392 6.60/8.40 0.1", not seen (and only 0.2" at discovery in 1843; physical with a 270-year period). AB-C is uncertain in WDS, but I find the stars do not share parallax ranges, -10%
Mark McCarthy Fremont (California/USA)	317mm (553x)	STF2607 (AB-C): Very close clean split though B is in A's diffraction, somewhat bluish.

★★

STF2606

7^m.7

8^m.4

0.7"

147°

2018

Cyg

19^h58^m32.66^s / +33°16'38.80"

Frederik Wanink Itterbeck (Germany)	254mm (640x)	sehr schwierig, Luftunruhe
Mark McCarthy Fremont (California/USA)	317mm (553x)	Hair split to clean split when seeing stills and there is only an airy disk. Near equal, half a delta mag. ~0.8"
Mark McCarthy Fremont (California/USA)	508mm (333x)	Close pair 2 delta mag.

A378

8^m.5

9^m.0

1.0"

294°

2016

Cyg

19^h59^m22.02^s / +32°06'28.00"

Mark McCarthy

Fremont (California/USA)

508mm (205x)

Excellent near equal split, light orange stars. Spectral class G5 (yellow). WDS 591-year period, and it appears to be starting to make a rapid closure to periastron by 2060. There is 37% parallax range overlap, 139 AU weighted separation, and 1.84/1.56 solar mass

STF2613

7^m.5

8^m.0

3.5"

354°

2020

Aql

20^h01^m26.66^s / +10°44'54.80"

René Merting Drachhausen (Germany)	100mm (64x)	64x reicht für die Trennung, dann stehen die beiden Sterne aber noch sehr dicht - beide mit gleicher Helligkeit und strahlend weiß - schick
Mark McCarthy Fremont (California/USA)	152mm (175x)	Lovely near equal white stars, good split. Physical with 2106-year period
Mark McCarthy Fremont (California/USA)	152mm (285x)	White, ~1 delta mag, nice wide split

STT395, 16 Vul

5^m.8

6^m.2

0.7"

129°

2020

Vul

20^h02^m01.45^s / +24°56'16.80"

Mark McCarthy Fremont (California/USA)	152mm (456x)	Slightly unequal snowman at all powers. Notching increases in strength with increasing power. Physical with 1201-year period
Mark McCarthy Fremont (California/USA)	203mm (667x)	16 Vul. Hairline split at 8" 333x. At 667x I see a more definite split. It appears only half delta mag, rather than the 1 delta mag in Sky Tools. Nice star.
Frederik Wanink Itterbeck (Germany)	254mm (640x)	fast getrennt, eher 8, ähnlich hell

Frederik Wanink

Itterbeck (Germany)

254mm

../projects/double-stars/frederik-wanink/photographs/16%20Vul.jpg

STT400

7^m.6

9^m.8

0.7"

329°

2017

Cyg

20^h10^m13.32^s / +43°56'44.20"

Mark McCarthy Fremont (California/USA)	152mm (245x)	Tough, notched elongation, near equal white stars. Physical with 85-year period, it is at apastron now will close entirely in the next 30 years
Mark McCarthy Fremont (California/USA)	508mm (445x)	Easy, nice clean disks, nicely split, 1 delta magnitude cream white A and light orange B, three field stars forming a triangle around it as reference. PA to NW. Spectral class G3V (yellow). Physical with 85.61-year period, it is 0.647" separated at apastron now and with make a quarter turn and tighten to 0.2" in the 2040s

STF2658

7^m.2

9^m.4

5.2"

106°

2020

Cyg

20^h13^m40.74^s / +53°07'30.30"

René Merting Drachhausen (Germany)	100mm (107x)	bei 107x ist Komponente B schwach erkennbar östlich von A, es ist schon ordentlich Luft zwischen den beiden - Helligkeitsunterschied 2 Magnituden
Uwe Pilz Leipzig (Germany)	105mm (144x)	orangegelb
Uwe Pilz Leipzig (Germany)	320mm (225x)

A1427 & STF2668

A1427

6^m.6

8^m.2

0.2"

132°

2012

Cyg

20^h20^m15.22^s / +39°24'11.80"

STF2668

AB-C

6^m.3

8^m.5

3.5"

280°

2016

René Merting Drachhausen (Germany)	100mm (107x)	STF2668 (AB-C): bei 64x klebt Komponente C ganz dicht westlich an AB - Helligkeitsunterschied gut 2.5 Größenklassen - bei 107x sind beide Sterne eindeutig knapp getrennt
Mark McCarthy Fremont (California/USA)	317mm (277x)	STF2668 (AB-C): White and reddish-brown B, ~3 delta mag., 2" or so.

★

COU327

9^m.1

0.2"

245°

2019

Del

20^h21^m35.69^s / +19°29'40.10"

Mark McCarthy

Fremont (California/USA)

508mm (1067x)

The AB-C pair is easy at 205x, C is a faint star ~4" separated from bright A (8.41/11.97 4.0"). AB is much more difficult. At 1067x it is mostly overlapping disks & I can tell its orientation. But at repeated best moments, I get an instant of the finest hairline split with noticeable magnitude difference & I can estimate an orientation relative to nearby stars. It's PA [246-degrees] is nearly perpendicular to AB-C [131-degrees] -- this is how I confirmed I have it. Cocteau discovered it in 1968 with the Nice 30-inch refractor at 0.2". 42.46 year period, last observation in 2005, with grade 3 orbit (which is certain but not definitive). It is currently coming off apastron with the current orbital solution at 0.167" separation. It will tighten very rapidly the next few years, but even on the opposite side of it's orbit it will not be detectable by me, I need to wait until 2050 to try again -- but since the PA will be similar I won't notice that change. I can only look forward to the tightening, and maybe detectability again. If is the 0.167" is correct I have exceeded the Raleigh, Dawes, and Sparrow criteria and it's a new personal best -- and given I did not split some similar pairs later in the night, I was very lucky with the seeing at the time of the observation

HO128

6^m.4

8^m.8

1.4"

357°

2016

Cyg

20^h22^m55.49^s / +42°59'00.40"

Mark McCarthy

Fremont (California/USA)

508mm (333x)

Nice gold and blue pair, split at 205x, wider split at 333x. WDS gives physical with a 1027.9807-year period, and the orbit will rapidly close to periastron the next few decades. While an orbit is given, there is NO parallax range overlap, -59%, so likely with time this will prove not to be a gravitationally bound pair

★

A288

8^m.7

9^m.0

0.2"

296°

2012

Del

20^h23^m08.98^s / +20°51'51.10"

Mark McCarthy

Fremont (California/USA)

508mm (1067x)

Hairline split, noticeable mag difference, white. Very fine pair. 163y period, it won't make an appreciable change in my time, though it will widen to the 1901 discovery separation of 0.3" in 2075

rho Cap, 11 Cap

SHJ323

5^m.0

6^m.9

1.7"

190°

2018

Cap

20^h28^m51.62^s / -17°48'49.20"

BU61

5^m.0

13^m.3

53.5"

149°

2015

SHJ323

5^m.0

6^m.7

258.7"

150°

2011

BU61

6^m.9

12^m.5

53.5"

149°

2015

DOB13

6^m.7

10^m.6

53.5"

93°

2020

René Merting Drachhausen (Germany)	12x50	AD: einfach, ein helles, weit auseinander stehendes Paar - Komponente B im SO ist gut 1.5 Magnituden schwächer und wirkt grau ggü. der weiß strahlenden Komponente A
René Merting Drachhausen (Germany)	15x56	AD: wieder eines jener Fernglaspaare, die unheimlich weit auseinander stehen - trotzdem auffällig, weil das Sternpaar recht isoliert erscheint - Komponente D wirkt grau und gut 1.5 Magnituden schwächer

A610

9^m.5

9^m.9

0.5"

93°

2018

Del

20^h29^m02.58^s / +07°09'29.30"

Mark McCarthy

Fremont (California/USA)

508mm (333x)

Very finely split, white near equal, nice. 170.62y period, will make less than a quarter turn the next couple of decades.

COU1962

9^m.0

9^m.5

0.2"

292°

2012

Cyg

20^h31^m07.72^s / +33°32'33.60"

Mark McCarthy

Fremont (California/USA)

508mm (889x)

Very tough, light orange stars, just barely split at best moments, almost 1 delta mag, PA to S. =V2425 Cyg, for which I don't find a light curve on AAVSO -- I assume it's easier to observe the split when this is at minima. Spectral class K0 (yellow-orange). Currently 0.119" ! Only a 20.414-year period, it will make a quarter turn and widen slightly by 2028, and reach apastron by 2033

★

STF2690 & HJ269 & DA1

STF2690

A-BC

7^m.1

7^m.4

17.8"

255°

2020

Del

20^h31^m11.94^s / +11°15'33.70"

HJ269

7^m.1

12^m.1

23.0"

108°

2016

DA1

7^m.9

8^m.0

0.3"

184°

2016

René Merting Drachhausen (Germany)	10x50	STF2690 (A-BC): ein ganz enges Sternpaar mit zwei gleich hellen Sternen - ich würde beide als 8 mit tiefer Einschnürung bezeichnen, also kurz vor der Trennung
Robert Zebahl Leipzig (Germany)	12x42	STF2690 (A-BC): 2021-10-09: Very nice. Clearly separated with almost equally bright components.
René Merting Drachhausen (Germany)	12x42	STF2690 (A-BC): ein superenges, schönes Paar gleich heller Sterne - da passen maximal eineinhalb Blatt Papier zwischen - schön im Zusammenspiel mit den beiden hellen Sternen südöstlich und südwestlich
Robert Zebahl Leipzig (Germany)	16x70	STF2690 (A-BC): 2020-08-19: Striking, moderately bright with nice separation of the similarly bright components in nice environment. The eastern component seemed slightly brighter and colorwise cooler.
Uwe Pilz Leipzig (Germany)	16x70	STF2690 (A-BC)
Uwe Pilz Leipzig (Germany)	16x70	STF2690 (A-BC): etwa gleichhell, sauber getrennt
René Merting Drachhausen (Germany)	100mm (20x)	STF2690 (A-BC): bei 32x ein schön getrenntes Sternpaar mit leichtem Farbkontrast - Komponente A im Osten ist weiß, BC im Westen ist leicht gelblich und dumpfer, aber kaum ein Helligkeitsunterschied zwischen beiden Sternen - zurück auf 20x ist das Paar noch schöner anzusehen, weil beide Sterne dichter zusammen stehen
Sarah Gebauer Germany	100mm (49x)	STF2690 (A-BC): weit getrennt, zwei simple Glupschäuglein im Leeren, mehr nicht
Robert Zebahl Leipzig (Germany)	102mm (28x)	STF2690 (A-BC): 2021-09-11: Very attractive, almost equally bright with subtle color contrast: pale yellow-orange & white-bluish.
Robert Zebahl Leipzig (Germany)	152mm (30x)	STF2690 (A-BC): 2021-09-08: Striking in nice star environment, easy to separate with little difference in brightness. Both components appeared slightly yellowish.
Mark McCarthy Fremont (California/USA)	317mm (277x)	STF2690 (A-BC): Widely separated near equal white stars.
Mark McCarthy Fremont (California/USA)	508mm (533x)	DA1 (BC): This is part of STF 2690 A-BC, which is a white, wide, near equal, pair (7.12/7.39 17.7") observed with 8-inch at 205x. I suspected BC at 8-inch 333x, & had overlapping disks with 8-inch 533x. With 20-inch 533x I see a hairline split, slight magnitude difference. Seeing is not supporting it well, but it's clear. Very nice. Dawes discovered in 1840 at 0.7" -- DA 1 was discovered when Dawes was working at "Mr Bishop's observatory" in London, from 1839 to 1844. It had a 7-inch refractor by Dollond (1836) who had made both mounting and telescope. So at current 0.369" it's not surprising I only had overlapping disks at 8-inch. It's a physical pair, with a 236.52 year period, and will widen another 0.1" in the next 15 years
Karsten Kopp Köln (Germany)	600mm (180x)	STF2690 (A-BC): STF 2690: Gut zu trennender Doppelstern mit leichtem Helligkeitsunterschied. Komponente A leuchtet weiß und die Komponente B geht ins gelbliche.

★

STF2695

6^m.6

8^m.8

0.3"

257°

2020

Vul

20^h31^m58.19^s / +25°48'18.10"

Mark McCarthy

Fremont (California/USA)

508mm (1067x)

Using 8" mask at 667x, no sign of elongation. With 20" and progressively higher magnifications, I can get to olive shape at 1067x, but extremely marginal. [0.8" at discovery, so easier for Struve]

10^m.0

10^m.6

1.9"

58°

2018

Del

20^h32^m52.76^s / +11°44'37.20"

Mark McCarthy

Fremont (California/USA)

203mm (205x)

Nice close pair, well split ~2", equal. Physical, at apastron, 528.391 year period (to be exact!)

HEI7, VW Cep

7^m.7

10^m.5

0.7"

231°

2007

Cep

20^h37^m21.54^s / +75°36'01.50"

Mark McCarthy

Fremont (California/USA)

508mm (333x)

Just glimpsed a speck in the diffraction ring when seeing stills, marginal

STT410

6^m.7

6^m.8

0.9"

3°

2018

Cyg

20^h39^m33.31^s / +40°34'46.80"

AB-C

6^m.8

8^m.7

68.6"

70°

2018

AB-D

6^m.8

10^m.0

106.6"

327°

2018

Uwe Pilz Leipzig (Germany)	105mm (198x)	AB: nur mäßig schwierig, Abstand 0“87
Uwe Pilz Leipzig (Germany)	105mm (288x)	AB: nicht getrennt
Robert Zebahl Leipzig (Germany)	152mm (240x)	AB: 2022-08-07: Two clearly visible diffraction disks that slightly touch each other. In a few moments a hint of separation is possible. A very slight difference in brightness can be seen at times.
Mark McCarthy Fremont (California/USA)	152mm (245x)	AB: Near equal, hairline split at best moments at 175x, good split at 245x. Blue-white stars with perfect airy disks! Physical with 1152-year period, is is nearing periastron and will make a relatively quick turn around the primary in the coming decades
Robert Zebahl Leipzig (Germany)	152mm (270x)	All four components easily visible. The pair AB shows two clear, equally bright, overlapping diffraction disks.
Frederik Wanink Itterbeck (Germany)	254mm (640x)	AB: gleich hell, getrennt

HDS2947

7^m.3

8^m.1

0.2"

112°

2020

Del

20^h40^m35.25^s / +15°38'35.30"

Mark McCarthy

Fremont (California/USA)

508mm (1067x)

With apodising mask. Not round is best I can say, marginal. Coming off apastron and only getting more difficult. Discovered 1991 by the Hipparcos satellite at 0.2"

BU152

7^m.2

8^m.8

1.2"

82°

2016

Cep

20^h42^m16.81^s / +57°23'07.40"

Mark McCarthy

Fremont (California/USA)

152mm (245x)

Beautifully fine, 2 delta mag, just split with 175x, better split at 245x. StelleDoppie says physical with a 737-year period, however there is no parallax range overlap (-25%), so they are not actually gravitationally bound!

STF2723

7^m.0

8^m.3

1.0"

140°

2018

Del

20^h44^m54.58^s / +12°18'45.60"

Mark McCarthy

Fremont (California/USA)

203mm (333x)

Very nice, light blue A and light yellow B, fine split, almost 2 delta mag. Really nice pair

★★

STF2725

7^m.5

8^m.2

6.2"

12°

2019

Del

20^h46^m13.31^s / +15°54'26.40"

Robert Zebahl Leipzig (Germany)	16x70	2021-09-02: The double star appears clearly elongated at the correct position angle, but nothing more.
René Merting Drachhausen (Germany)	100mm (32x)	bei 32x ein schöner Kontrast zum 15' nördlich stehenden viel helleren Sternpaar STF2727 - hier bei dem wesentlich schwächeren Sternpaar zeigt sich bei 32x die Komponente B knapp getrennt nördlich von A - Helligkeitsunterschied etwas mehr als eine halbe Magnitude, aber Komponente A ist noch deutlich schwächer als die Komponente B von STF2727
Sarah Gebauer Germany	100mm (45x)	das Doppel lässt sich bei 45x sauber trennen und bildet mit Gamma2 Delphini ein optisches Doppel-Doppel, da beide Doppelsterne sehr gut in ein Gesichtsfeld passen
Uwe Pilz Leipzig (Germany)	105mm (66x)	im selben Feld mit gamma Del
Uwe Pilz Leipzig (Germany)	105mm (88x)
Robert Zebahl Leipzig (Germany)	152mm (30x)	2021-09-11: Separated but still very close components with moderate brightness difference.
Mark McCarthy Fremont (California/USA)	203mm (205x)	OR Del. Light yellow stars, half delta mag, wide. Physical pair with a 2945.18 year period. In same field with bright pair STF 2727
Mark McCarthy Fremont (California/USA)	317mm (553x)	Super wide, 1 magnitude difference, both faint yellow-white.
Mark McCarthy Fremont (California/USA)	508mm (333x)	Easy, half delta mag and wide. I was after the super close WSI 110 Aa-Ab 0.1" but had no hope of seeing it.
Karsten Kopp Köln (Germany)	600mm (180x)	Leicht zu trennender Doppelstern mit leichtem Helligkeitsunterschied von ca. 0,5 mag. Komponente A leuchtet weißlich und die Komponente B b gelblich.

Berthold Fuchs

Wiesbaden (Germany)

130mm

close DS

../projects/double-stars/berthold-fuchs/photographs/STF%202725.png

★★

STF2727, 12 Del, gamma Del

4^m.4

5^m.0

8.8"

266°

2020

Del

20^h46^m39.50^s / +16°07'27.40"

Christopher Hay Seeheim (Germany)	8x42	On tripod. Definite elongation, and eastern end of elongation (i.e. component A) is definitely brighter than the other end. PA estimated at 240° without prior knowledge.
Christopher Hay Seeheim (Germany)	15x45	Stabilised binoculars, handheld. A very elongated figure-8 very close to popping apart. According to Stelledoppie a physical double with a period of 3249 years. Observed in June 2019 when separation was 8,89“. Will be 8.67“ in 2030 according to Stelledoppie.
Robert Zebahl Leipzig (Germany)	16x70	2021-09-02: Beautiful sight in very nice surrounding. Easy to split, but quite small separation. A rather small difference in brightness is clearly visible. The primary component appears golden in color.
Christopher Hay Seeheim (Germany)	18x80	Very tight pair but clearly split with black in-between. Observed in July 2019 when separation was 8,89“. An excellent object to test the resolution of large binoculars. Struve 2725 a few arcminutes to the southwest is a further good test object for magnifications >20x.
Christopher Hay Seeheim (Germany)	40x80	Widely split, visually strong, dominating the field of view. Component A appears yellowish compared to component B. Struve 2725 in same FOV finely split.
René Merting Drachhausen (Germany)	100mm (32x)	bei 32x knapp getrennt - Komponente A ist schön gelb, B im Westen ist gut 1.5 Magnituden schwächer (lt. Stelle Doppie Helligkeitsunterschied nur 0.67 mag) - zusammen mit dem wesentlich schwächeren STF2725 gut 15' südlich sehenswert
Sarah Gebauer Germany	100mm (45x)	bei 45x sauber getrennt und zusammen mit dem DS STF 2725 in einem Gesichtsfeld, dadurch wirken sie wie ein optisches Doppel-Doppel, sehr schön! Beide DS bilden auch einen auffälligen Lichthof
Uwe Pilz Leipzig (Germany)	105mm (66x)	im selben Feld mit STF2725
Uwe Pilz Leipzig (Germany)	105mm (144x)	schon trennbar bei 26x. In einem Feld mit STF2725
Robert Zebahl Leipzig (Germany)	152mm (30x)	2021-09-11: Difference in brightness well visible. Light yellow/golden & lemon yellow.
Mark McCarthy Fremont (California/USA)	152mm (175x)	Gam2 Del. Gorgeous, light yellow-orange A and blue-green B, I like this better than Albireo. Physical with 3249-year period, it will slowly tighten the next couple of hundred years
Mark McCarthy Fremont (California/USA)	152mm (285x)	Gam 2 Del. ! Most beautiful light orange-yellow A and ~1 delta mag blue-green B
Mark McCarthy Fremont (California/USA)	317mm (277x)	Gamma Delphinus. Rich gold-yellow A, blue-white B, ~6" separation estimated by eye. Very pretty pair.
Karsten Kopp Köln (Germany)	600mm (180x)	Recht heller und auch leicht zu trennender Doppelstern mit ca. 0,5 mag Helligkeitsunterschied. Komponente A leuchtet schön gelblich und Komponente B weiß.

★

STT413, 54 Cyg, lambda Cyg

4^m.7

6^m.3

0.9"

1°

2020

Cyg

20^h47^m24.53^s / +36°29'26.70"

Robert Zebahl Leipzig (Germany)	102mm (280x)	The diffraction disk of the primary component was slightly elongated towards north. The air here was however a bit too unsteady for an accurate observation.
Uwe Pilz Leipzig (Germany)	105mm	schwierig
Mark McCarthy Fremont (California/USA)	152mm (175x)	Very unequal mag snowman. Physical with an 800-year period
Robert Zebahl Leipzig (Germany)	152mm (300x)	Observation with an achromat. The fainter component was visible as a permanent brightening of the first diffraction ring.
Robert Zebahl Leipzig (Germany)	152mm (300x)	2020-08-24: Observation with an ED refractor. At 171x partially, at 200x clearly visible as '8'. At 300x two clear, overlapping diffraction disks of differently bright components.
Frederik Wanink Itterbeck (Germany)	254mm (640x)	schwierig aber getrennt
Mark McCarthy Fremont (California/USA)	317mm (553x)	Lambda Cyg: ~1.5 delta mag, blue-white. Bright mess resolves to two disks 0.8-1.0", with seeing.

BU155

7^m.4

8^m.1

0.7"

41°

2018

Cyg

20^h51^m05.41^s / +51°25'01.70"

7^m.4

12^m.6

14.8"

40°

2015

7^m.4

11^m.5

191.8"

48°

2015

Robert Zebahl Leipzig (Germany)	152mm (300x)	AB: 2022-08-07: At 200x slightly elongated, at 240x clearly elongated, at 300x slightly notched in steady moments.
Mark McCarthy Fremont (California/USA)	152mm (380x)	AB: Can tell it is not single ay 175x, and appears slightly notched at 245x. Strongly notched but not split at 380x. WDS physical with a 764-year period, unfortunately there is no parallax data for the companion. Burnham discovered with his 6-inch at 0.6" and notes "A fine pair, but no material change." He does not say whether he split it, though to do so would require a night of exceptional seeing to carry high magnification. Dembowski -- who had a 7-inch -- must also have had a good night to be able to put it under the wire for measurement. The thing about Burnham is he was a very attentive observer, I could imagine many others passing this over had they not studied the airy disk carefully
Frederik Wanink Itterbeck (Germany)	254mm (640x)	AB: getrennt

A613

9^m.1

9^m.0

0.7"

324°

2018

Del

20^h51^m54.49^s / +05°44'29.50"

Mark McCarthy

Fremont (California/USA)

203mm (533x)

Getting the briefest hairline split, but this one is very marginal seeing is a problem

STT418

8^m.2

8^m.3

0.9"

284°

2018

Cyg

20^h54^m49.84^s / +32°42'23.20"

Mark McCarthy Fremont (California/USA)	152mm (285x)	Incredibly fine split, near equal. Suspected at 175x. Physical with a 709-year period
Frederik Wanink Itterbeck (Germany)	254mm (640x)	getrennt, gleich hell
Mark McCarthy Fremont (California/USA)	317mm (553x)	Near equal 1" split, white.

Frederik Wanink

Itterbeck (Germany)

254mm

../projects/double-stars/frederik-wanink/photographs/STT%20418.jpg

★

STF2737, epsilon Equ, 1 Equ

6^m.0

6^m.3

0.0"

261°

2020

Equ

20^h59^m04.54^s / +04°17'37.80"

AB-C

5^m.3

7^m.0

10.6"

67°

2019

6^m.0

13^m.1

69.3"

293°

2013

René Merting Drachhausen (Germany)	12x50	AB-C: in ruhigen Momenten präsentieren sich beide Sterne länglich mit Einschnürung, dann sieht das System aus wie eine kleine Ameise
Robert Zebahl Leipzig (Germany)	70mm (22x)	AB-C: At 22x well separated, but still relatively close together with a clear difference in brightness. At 44x AB looked rather white. The color of C was not apparent.
Christopher Hay Seeheim (Germany)	80mm (30x)	AB-C: Well split, C bluish, AB no definite colour, a nice pair at this power. According to Stelledoppie B and C are a physical pair with a period of 5200 years, and A and B are again a physical pair with a period of 104 years.
René Merting Drachhausen (Germany)	100mm (32x)	AB-C: bei 32x knapp getrennt - Komponente AB mit einem schönen cremegelb, C steht nordöstlich und ist gut 1.5 Größenklassen schwächer
Sarah Gebauer Germany	100mm (45x)	AB-C: bei 45x ganz eng, aber sauber getrennt, die hellere Komponente AB ist gelbstichig und die nordöstliche, schwächere Komponente C hat phasenweise einen Blaustich, wie ein ganz enger, ganz kleiner und schwächerer Albireo
Mark McCarthy Fremont (California/USA)	317mm (553x)	AB-C: Easy yellow stars, very wide, 1 delta mag.
Mark McCarthy Fremont (California/USA)	317mm (553x)	AB: 1 Equ / Epsilon Equ / Strongly feel an oval AB pairing, marginal

Berthold Fuchs

Wiesbaden (Germany)

130mm

AB-C: close DS

../projects/double-stars/berthold-fuchs/photographs/1%20Equulei.png

59 Cyg, STF2743

MCA65

Aa-Ab

4^m.8

7^m.6

0.1"

334°

2015

Cyg

20^h59^m49.55^s / +47°31'15.40"

STF2743

4^m.7

9^m.4

21.0"

353°

2012

STF2743

4^m.7

11^m.6

26.5"

140°

2012

STF2743

4^m.7

11^m.2

39.3"

222°

2012

STF2743

4^m.7

12^m.0

70.6"

59°

2003

Christopher Hay Seeheim (Germany)	125mm (64x)	AB: Widely split and striking in field of view, as the pair is a little outside of the star cloud at the swan's tail that adjoins to the south. The A component appears yellowish. The attraction lies in the B component with delta-mag 4m6, which presents as a fine grey-blue pinprick of light. Alias 59 Cygni.
René Merting Drachhausen (Germany)	320mm (72x)	AB: bei 45x ist Komponente B nördlich von A erkennbar - Komponente A strahlend weiß, bei B ist keine Farbe erkennbar, mindestens 4 Größenklassen Helligkeitsunterschied AD: bei 72x ist Komponente D südwestlich von A in doppeltem Abstand wie AB erkennbar AE: bei 72x ist Komponente E nordöstlich von A in doppeltem Abstand wie AD und noch schwächer als D erkennbar

KUI102

6^m.2

8^m.1

0.2"

213°

2018

Equ

21^h00^m03.95^s / +07°30'58.20"

Mark McCarthy

Fremont (California/USA)

508mm (667x)

Overlapping disks, strongly notched, white stars, PA to south. Currently 0.22" it will continue to widen into the 2040s. 58.4-year period

★

BU69

8^m.3

9^m.8

0.4"

6°

2017

Vul

21^h02^m36.08^s / +21°41'28.20"

Mark McCarthy

Fremont (California/USA)

317mm (553x)

I sense overlapping disks at 553x, but marginal.

★

BU1138

7^m.1

7^m.3

0.1"

172°

2006

Cyg

21^h02^m48.62^s / +45°50'56.00"

Mark McCarthy

Fremont (California/USA)

508mm (1067x)

Notched elongation with seeing and apodising mask, white, can tell A and B's orientation by difference in magnitude. Current separation 0.155". 314 year period, it will only make modest position angle change in my time. Burnham discovered in 1888 with the Lick 36-inch at 0.3"! It seems Hough also discovered it in 1888 but published his results later, HO 282

STF2744

6^m.8

7^m