- Double Stars (UMa) -

And (32)	Cep (13)	CVn (4)	Her (13)	Mon (1)	Sex (2)
Aql (9)	Cet (1)	Cyg (19)	Hya (4)	Oph (1)	Tau (11)
Ari (8)	CMa (1)	Del (2)	Leo (19)	Ori (8)	Tri (4)
Aur (27)	Cnc (10)	Dra (8)	Lib (1)	Peg (16)	UMa (24)
Boo (12)	Com (8)	Equ (5)	LMi (6)	Per (18)	UMi (1)
Cam (10)	CrB (4)	Eri (1)	Lyn (18)	Psc (7)	Vir (6)
Cas (17)	Crv (1)	Gem (19)	Lyr (8)	Ser (2)

41 Lyn (**)

Name:	41 Lyn, S598
Type:	**
Constellation:	UMa
Coordinates:	09h28m39.99s / +45°36'06.50"

Components:
		m₁	m₂	ρ	θ	Year
	AB	5m5	7m8	69.7"	160°	2017


This star has the designation 41 Lyn but is assigned to UMa. At the time, when Flamsteed numbered the stars, the constellation boundaries were not exactly defined. Another example is 10 UMa, which is located in Lyn today.
Robert Zebahl
B 8x40, Bortle 7, NELM 5m0, SQM-L 19.2 Fairly well split with fainter component.

67 UMa (**)

Name:	67 UMa
Type:	**
Constellation:	UMa
Coordinates:	12h02m06.80s / +43°02'44.30"

Components:
		m₁	m₂	ρ	θ	Year
FOR1	AB	5m2	6m7	274.4"	62°	2015
ARN5	AC	5m2	8m5	375.9"	25°	2015
FOR1	AD	5m2	8m9	363.2"	268°	2015

Robert Zebahl
B 8x40 2020-04-05: The pair AB stands out immediately and shows itself in beautiful colors: A white-yellowish, B slightly orange. Almost at right angles to pair AB component C is visible as a faint star at a slightly smaller distance. I did not pay attention to the even fainter component D.
55mm f/9.1, 27x 2020-04-05: Components A, B and C easily visible with decreasing brightness. I did not consider component D. A: white-yellowish, B: pale orange. I liked the view in the 8x40 binoculars better.

BU 1077 (**)

Name:	BU1077, alpha UMa, 50 UMa, Dubhe
Type:	**
Constellation:	UMa
Coordinates:	11h03m43.84s / +61°45'04.00"

Components:
		m₁	m₂	ρ	θ	Year
	AB	2m0	5m0	0.8"	342°	2017
	AC	2m0	7m2	370.0"	205°	2015



Robert Zebahl
70mm f/5.7, 22x AC: 2020-04-07: Very wide, uneven & inconspicuous pair. A appeared white-yellowish, for B I could not detect any color.

STF 1258 (**)

Name:	STF1258
Type:	**
Constellation:	UMa
Coordinates:	08h43m25.41s / +48°51'41.90"

Components:
	m₁	m₂	ρ	θ	Year
	7m7	7m9	10.0"	330°	2017

Robert Zebahl
70mm f/5.7, 22x, Seeing 3/5 Easy to separate at 22x, similarly bright components at moderate distance. At 57x very small difference in brightness noticeable. The components appeared slightly orange and white-bluish, with the color changing from one component to another. A very strange effect, which I observed several times.

STF 1275 (**)

Name:	STF1275
Type:	**
Constellation:	UMa
Coordinates:	08h51m26.19s / +57°31'38.10"

Components:
		m₁	m₂	ρ	θ	Year
	AB	8m7	8m9	1.9"	198°	2019

Robert Zebahl
70mm f/5.7, 100x At 100x and 150x not permanently split. Components very close together.

STF 1306 (**)

Name:	STF1306, sigma 2 UMa, 13 UMa
Type:	**
Constellation:	UMa
Coordinates:	09h10m23.53s / +67°08'03.30"

Components:
		m₁	m₂	ρ	θ	Year
	AB	4m9	8m8	4.3"	348°	2016
	AC	4m9	10m3	197.8"	148°	2003



Robert Zebahl
70mm f/5.7, 100x, Seeing 3/5 AB: Companion almost permanently visible as elongated, non-condensed brightening of the first diffraction ring of the primary component at the correct position angle.

STF 1315 (**)

Name:	STF1315
Type:	**
Constellation:	UMa
Coordinates:	09h12m45.94s / +61°40'32.70"

Components:
	m₁	m₂	ρ	θ	Year
	7m3	7m7	24.9"	27°	2017

Robert Zebahl
70mm f/5.7, 22x, Seeing 3/5 Medium bright double star, easy to separate with attractive distance and slight difference in brightness. Together with 16 UMa in one field of view. The brighter component appeared slightly orange, the fainter one showed a hint of blue. However, the colors of the components changed over time. At 57x similar view.

STF 1318 (**)

Name:	STF1318
Type:	**
Constellation:	UMa
Coordinates:	09h13m38.79s / +46°59'25.30"

Components:
	m₁	m₂	ρ	θ	Year
	7m8	9m5	2.4"	228°	2018

Robert Zebahl
70mm f/5.7, 133x, Bortle 6, SQM-L 19.4 Separated with clear difference in brightness. The faint companion is slightly outside the first diffraction ring of the primary component.

STF 1321 (**)

Name:	STF1321
Type:	**
Constellation:	UMa
Coordinates:	09h14m22.79s / +52°41'11.80"

Components:
		m₁	m₂	ρ	θ	Year
	AB	7m8	7m9	17.0"	98°	2018
	AC	7m8	14m5	145.7"	64°	2010
	AD	7m8	11m9	136.4"	129°	2015



Robert Zebahl
70mm f/5.7, 22x, Bortle 6 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.

STF 1331 (**)

Name:	STF1331
Type:	**
Constellation:	UMa
Coordinates:	09h20m46.02s / +61°20'58.40"

Components:
		m₁	m₂	ρ	θ	Year
	AB	8m5	8m7	0.9"	153°	2017
	AC	8m5	11m6	13.5"	186°	2015
	AD	8m5	14m5	19.4"	117°	2015
	AE	8m5	9m8	139.1"	223°	2015

Robert Zebahl

152mm f/5.9, 180x, Bortle 6, SQM-L 19.4
2020-04-13: The wide pair AE is already visible at 22x with a significant difference in brightness, but quite inconspicuous. A appeared white-yellowish, E rather orange. The close pair AB appeared immediately elongated at 129x, partly visible as '8'. At 180x, AB was just separated with a fine black space between them. The faint C component was only visible with averted vision. Best view at 180x. The even fainter D component was out of range.

STF 1350 (**)

Name:	STF1350
Type:	**
Constellation:	UMa
Coordinates:	09h34m19.56s / +66°47'42.30"

Components:
		m₁	m₂	ρ	θ	Year
	AB	8m3	8m3	10.2"	249°	2015
	AC	8m3	9m2	131.0"	216°	2015

Robert Zebahl

152mm f/5.9, 100x, Bortle 6-, SQM-L 19.1
At 22x, all three components are already visible, with A & B still standing quite close together. Component C is less prominent. At 69x and 100x, the pair AB shows a nice color contrast: The eastern component mostly appeared in a slightly shiny orange, while the other component appeared more white-bluish. During the observation, however, the colors changed between both components. At the time of observation, the pretty bright comet C/2019 Y4 Atlas was also in the same field of view - a great scene! Note to the sketch: The positions of the stars to each other do not exactly match, also the alignment of the pair AB to C.

STF 1351 (**)

Name:	STF1351, 23 UMa
Type:	**
Constellation:	UMa
Coordinates:	09h31m31.57s / +63°03'42.50"

Components:
		m₁	m₂	ρ	θ	Year
	AB	3m6	9m2	22.7"	267°	2015
	AC	3m7	11m8	107.4"	232°	2015

Robert Zebahl
70mm f/5.7, 22x AB: 2020-04-07: Well separable with a significant difference in brightness, where the companion appearing only as a tiny star close to the primary component. The primary component itself appeared bright and rather whitish.

STF 1415 (**)

Name:	STF1415
Type:	**
Constellation:	UMa
Coordinates:	10h17m50.61s / +71°03'38.90"

Components:
		m₁	m₂	ρ	θ	Year
	AB	6m7	7m3	16.6"	168°	2018
	AC	6m7	10m8	153.3"	13°	2015

Robert Zebahl
70mm f/5.7, 22x AB: 2020-04-07: At 22x immediately noticeable as double star, medium bright with rather small difference in brightness. A appeared whitish, B slightly orange, partly brownish. At 44x similar color impression: A white-bluish, B slightly orange.

STF 1505 (**)

Name:	STF1505
Type:	**
Constellation:	UMa
Coordinates:	11h05m41.23s / +62°37'01.50"

Components:
		m₁	m₂	ρ	θ	Year
	AB	8m9	10m6	8.2"	312°	2015
	AC	8m9	12m0	217.7"	177°	2015

Robert Zebahl
70mm f/5.7, 80x, Bortle 6, NELM 5m0+ AB: 2020-04-14: Easy split with pretty dim companion.

STF 1520 (**)

Name:	STF1520
Type:	**
Constellation:	UMa
Coordinates:	11h16m04.03s / +52°46'23.40"

Components:
	m₁	m₂	ρ	θ	Year
	6m5	7m8	12.4"	344°	2017

Robert Zebahl
70mm f/5.7, 44x 2020-04-08: At 22x pretty tight, uneven pair. A appeared orange, B did not show any clear color. At 44x, A appeared yellowish-orange, B silvery grey, partly grey-bluish.

STF 1523 (**)

Name:	STF1523, xi UMa, 53 UMa, Alula Australis
Type:	**
Constellation:	UMa
Coordinates:	11h18m10.90s / +31°31'45.00"

Components:
		m₁	m₂	ρ	θ	Year
	AB	4m3	4m8	2.1"	155°	2019



Robert Zebahl
55mm f/9.1, 83x, Bortle 6-, SQM-L 19.1 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.
70mm f/5.7, 100x, Bortle 6 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.
70mm f/5.7, 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.
102mm f/11, 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.
120mm f/5, 168x, Bortle 6, SQM-L 19.1 2018-02-14: Well split with slight difference in brightness.
152mm f/5.9, 129x, Bortle 6, NELM 5m0+ 2019-02-06: Well split with visible difference in brightness. The colors of both components appeared equal.

STF 1559 (**)

Name:	STF1559
Type:	**
Constellation:	UMa
Coordinates:	11h38m49.11s / +64°20'49.40"

Components:
	m₁	m₂	ρ	θ	Year
	6m8	8m0	1.9"	328°	2017

Robert Zebahl
70mm f/5.7, 133x, Bortle 6, NELM 5m0+ 2020-04-14: Two clearly visible, slightly touching diffraction disks. The fainter companion appeared somewhat more diffuse. Occasionally the double star appeared separated.

STF 1561 (**)

Name:	STF1561
Type:	**
Constellation:	UMa
Coordinates:	11h38m44.90s / +45°06'30.30"

Components:
		m₁	m₂	ρ	θ	Year
	AB	6m5	8m2	8.9"	247°	2017
	AC	6m5	9m5	176.8"	90°	2015
	AD	6m5	7m6	718.2"	76°	2015
	AE	6m5	12m1	60.7"	338°	2015



Robert Zebahl
70mm f/5.7, 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.

STF 1579 (**)

Name:	STF1579, 65 UMa
Type:	**
Constellation:	UMa
Coordinates:	11h55m05.74s / +46°28'36.60"

Components:
		m₁	m₂	ρ	θ	Year
	AB-C	6m7	8m3	3.8"	40°	2017
	AB-D	6m7	7m0	62.5"	114°	2018

Robert Zebahl
B 8x40 AB-D: 2020-04-05: Immediately conspicuous in the field. Medium bright double star with slightly uneven components. Western component AB appeared slightly orange, component D tended to be bluish.
55mm f/9.1, 83x, Bortle 6-, SQM-L 19.1 2019-02-09: AB, C & D easy to split, but the faint C component only appeared as a tiny star. To the south there is the brighter D component.
55mm f/9.1, 27x, Bortle 6-, SQM-L 19.1 AB-D: Easy to separate with large distance and very small difference in brightness. The D component showed a bluish tint, the lighter one (AB) a slightly yellowish tint. At higher magnification also the faint C component is visible.

STF 1603 (**)

Name:	STF1603
Type:	**
Constellation:	UMa
Coordinates:	12h08m07.07s / +55°27'50.70"

Components:
	m₁	m₂	ρ	θ	Year
	7m8	8m3	22.5"	85°	2018

Robert Zebahl
70mm f/5.7, 22x 2020-04-07: At 22x quite apparent double star in rather poor surrounding. Nice separation with little difference in brightness. Primary component appeared slightly orange, companion grey-bluish. At 44x similar view in color appearance.

STF 1695 (**)

Name:	STF1695
Type:	**
Constellation:	UMa
Coordinates:	12h56m17.64s / +54°05'58.10"

Components:
		m₁	m₂	ρ	θ	Year
	AB	6m0	7m8	3.9"	281°	2017
	AC	6m0	12m3	131.7"	139°	2015

Robert Zebahl
70mm f/5.7, 57x, Bortle 6- AB: Easily separable, but still quite close together with a relatively large difference in brightness. The companion appeared only as a tiny star.

STF 1830 & STF1831 (**)

Name:	STF1830 & STF1831
Type:	**
Constellation:	UMa
Coordinates:	14h16m08.47s / +56°42'45.70"

Components:
		m₁	m₂	ρ	θ	Year
STF1831	AB	7m2	9m6	5.8"	138°	2017
STF1831	AC	7m2	6m7	112.2"	219°	2017
STF1831	CD	6m7	13m1	112.1"	116°	2016
STF1830	CE	6m7	9m3	138.0"	245°	2016
STF1830	EF	9m3	10m3	10.6"	312°	2017
STF1830	EG	9m3	12m2	35.2"	81°	2017

Robert Zebahl
B 8x40 STF1831 (AC): 2020-04-05: Fairly wide pair with slight differences in brightness and color. C appeared slightly orange, A on the other hand slightly bluish. Comparatively bright double star, which gives a nice view.
55mm f/9.1, 27x STF1831 (AC): 2020-04-05: Moderate difference in brightness. C: pale orange, A: subtle blue.
70mm f/5.7, 57x, Bortle 6 2020-04-11: At 22x the components AB, C, E & F are well visible and widely separated. E & F are comparatively faint. The C component in the middle appeared white-yellowish, AB rather white with a slight tendency to blue. At 57x, the pair AB with a clear difference in brightness can be easily split. An altogether rewarding and unusual multiple system.

VBS 18 & CSN7 (**)

Name:	VBS18 & CSN7, WX UMa
Type:	**
Constellation:	UMa
Coordinates:	11h05m27.65s / +43°31'38.70"

Components:
		m₁	m₂	ρ	θ	Year
VBS18	AB	8m8	14m6	32.0"	125°	2017
CSN7	AC	4m8	7m5	7.3"	168°	2003

Robert Zebahl
70mm f/5.7, 100x, Seeing 3-4/5 AC: 2020-03-31: Not identifiable at magnifications between 22x and 100x. WX UMa (component A?) is a variable (b14m2-16m53) and probably too faint.

zeta UMa (**)

Name:	zeta UMa
Type:	**
Constellation:	UMa
Coordinates:	13h23m55.42s / +54°55'31.50"

Components:
		m₁	m₂	ρ	θ	Year
STF1744, 79 UMa, Mizar	AB	2m2	3m9	14.4"	153°	2017
STF1744, Mizar & Alcor	AC	2m2	4m0	707.7"	72°	2017
SMR4	AD	2m2	7m6	492.8"	102°	2017

Robert Zebahl
B 8x40 AB: 2020-04-05: Even with tripod not separable.
70mm f/5.7, 10x AB: 2020-04-12: Observation from city with a 70/400mm ED refractor, for which I made aperture masks from 10mm to 60mm. Goal was to find the minimum magnification for a successful split. 70mm: At 12.5x no separation of the components possible due to outshining. Grey filters brought a slight improvement, but again no separation or elongation was visible. 60mm: At 12.5x slight outshining of the companion, clearly elongated and almost separated. 50mm: At 12.5x the companion was almost outshined. A separation was just possible. 40mm: At 12.5x both components appear finely separated from each other. 30mm: At 10x not clearly separable due to outshining, but clearly elongated. At 12.5x then quite easy to separate with a fine star rendition. 20mm: At 10x the companion is still clearly visible, but quite close to the primary component. At 12.5x best view under the used apertures with a very fine rendition! 10mm: At 10x the companion appears very faint. Separation possible, but extremely tight. At 12.5x reasonably well separated.
70mm f/5.7, 22x, Bortle 6 AB: 2020-04-11: At 12x no separation possible, because the bright primary component outshines the companion. At 22x clearly separated, but still quite close together.
102mm f/11, 28x First pastel sketch (Pitt pastel by Faber-Castell) of a double star on black paper, where also the halos were sketched around the stars. The stars themselves were redrawn with an Edding (Edding 1500, Soft Pastel white). The sketch shows the components A to D.