- Double Stars (UMa) -

And (32) Cep (13) CVn (4) Her (13) Mon (1) Sex (1)
Aql (9) Cet (1) Cyg (19) Hya (1) Oph (1) Tau (11)
Ari (8) CMa (1) Del (2) Leo (14) Ori (8) Tri (4)
Aur (27) Cnc (10) Dra (8) Lib (1) Peg (16) UMa (11)
Boo (8) Com (1) Equ (5) LMi (4) Per (18) UMi (1)
Cam (5) CrB (4) Eri (1) Lyn (16) 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.

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

../images/binary-star-orbits/STF1306-AB-orbit.jpg

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 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.

../sketches/2020-03-18_stf1350_c2019_y4_atlas.jpg

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

../images/binary-star-orbits/STF1523-AB-orbit.jpg

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.

../sketches/2019-02-09_xi_uma.jpg

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 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
55mm f/9.1, 83x, Bortle 6-, SQM-L 19.1
AB-C: Easy to split, but the faint C component only appeared as a tiny star.

../sketches/2019-02-09_65_uma.jpg

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 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.

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
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.

../sketches/2019-08-14_mizar_alcor.jpg