- Double Stars (Tau) -

And (43) Cet (1) Del (4) Lib (1) Per (27) UMi (1)
Aql (9) CMa (2) Dra (11) LMi (6) Psc (10) Vir (9)
Ari (8) Cnc (10) Equ (5) Lyn (18) Pup (1) Vul (3)
Aur (28) Com (8) Eri (1) Lyr (11) Ser (3)
Boo (20) CrB (4) Gem (22) Mon (1) Sex (2)
Cam (11) Crv (1) Her (16) Oph (1) Tau (11)
Cas (17) CVn (14) Hya (4) Ori (9) Tri (4)
Cep (13) Cyg (26) Leo (24) Peg (16) UMa (38)

STF 401 (**)
Name: STF401
Type: **
Constellation: Tau
Coordinates: 03h31m20.76s / +27°34'18.50"

Components:
m1 m2 ρ θ Year
AB 6m6 6m9 11.5" 270° 2018
Robert Zebahl
120mm f/5, 18x, Bortle 6-, NELM 4m8+, SQM-L 19.1
Barely split at 18x. At 40x difference in brightness is visible. Nice view together with the double star STFA7 located northwest.

STF 427 (**)
Name: STF427, V1268 Tau
Type: **
Constellation: Tau
Coordinates: 03h40m38.77s / +28°46'24.00"

Components:
m1 m2 ρ θ Year
7m4 7m8 7.0" 207° 2016
Robert Zebahl
120mm f/5, 40x, Bortle 6-, NELM 4m8+, SQM-L 19.1
At 40x barely split. At 75x easily split with visible difference in brightness.

STF 479 (**)
Name: STF479
Type: **
Constellation: Tau
Coordinates: 04h00m56.81s / +23°12'05.40"

Components:
m1 m2 ρ θ Year
AB 6m9 7m8 7.5" 127° 2018
AC 6m9 9m4 57.7" 243° 2018
Robert Zebahl
102mm f/11, 28x, Bortle 6, SQM-L 19.3, Seeing 2/5
Components A & B clearly separated with visible difference in brightness. Noticeably fainter component C much wider apart. All three components form an obtuse triangle.
152mm f/5.9, 49x, Bortle 6, SQM-L 19.3, Seeing 2/5
Nice view. All three components easy to separate. A: white-yellowish; B: creamy white.
8" f/6, 37x, Bortle 4, SQM-L 21.00
AB: Nice, evident double star, easy to split. Slight difference in brightness.

STF 494 (**)
Name: STF494
Type: **
Constellation: Tau
Coordinates: 04h08m53.50s / +23°05'55.10"

Components:
m1 m2 ρ θ Year
7m5 7m7 5.3" 188° 2018
Robert Zebahl
102mm f/11, 62x, Bortle 6, SQM-L 19.3, Seeing 2/5
At 28x separated, but very tight, similarly bright, both whitish. At 62x easy to separate, little difference in brightness and color: slightly orange; white-bluish. Color impression slightly more intense at 86x.
152mm f/5.9, 49x, Bortle 6, SQM-L 19.3, Seeing 2/5
Easy to separate at 49x with subtle color differences: slightly orange; white-bluish. Color impression slightly more intense at 100x. Beautiful sight.

STF 559 (**)
Name: STF559
Type: **
Constellation: Tau
Coordinates: 04h33m33.04s / +18°01'00.20"

Components:
m1 m2 ρ θ Year
7m0 7m0 3.0" 277° 2018
Robert Zebahl
70mm f/5.7, 57x
Barely split with similarly bright components.
102mm f/11, 160x
Very nice view! Easy to separate, similarly bright at a nice distance from each other. The colors of the components changed over time: orange and subtle blue.
152mm f/5.9, 69x
Beautiful sight, similar bright components, pretty tight.

STF 572 (**)
Name: STF572
Type: **
Constellation: Tau
Coordinates: 04h38m29.58s / +26°56'25.60"

Components:
m1 m2 ρ θ Year
AB 7m4 7m2 4.4" 189° 2018

../images/binary-star-orbits/STF572-AB-orbit.jpg

Robert Zebahl
70mm f/5.7, 57x
Clearly separated, easy with beautiful color contrast: A slightly orange, B white.

STF 716 (**)
Name: STF716, 118 Tau
Type: **
Constellation: Tau
Coordinates: 05h29m16.49s / +25°09'01.10"

Components:
m1 m2 ρ θ Year
AB 5m8 6m7 4.9" 209° 2019
AC 5m8 11m9 140.2" 99° 2001
Robert Zebahl
70mm f/5.7, 33x
AB: At 33x very tight with visible difference in brightness. At 47x very nice view. Both components appeared white.

STF 730 (**)
Name: STF730
Type: **
Constellation: Tau
Coordinates: 05h32m14.14s / +17°03'29.30"

Components:
m1 m2 ρ θ Year
AB 6m1 6m4 9.7" 142° 2018
Robert Zebahl
70mm f/5.7, 22x
At 22x beautiful sight, easy to separate with little difference in brightness. A appeared slightly yellowish. At 57x moderate, but still very nice color contrast: A yellowish, B rather white.

STF 742 (**)
Name: STF742
Type: **
Constellation: Tau
Coordinates: 05h36m26.38s / +21°59'35.10"

Components:
m1 m2 ρ θ Year
7m1 7m5 4.2" 275° 2019
Located about 0.5 degree east of Messier 1.

../images/binary-star-orbits/STF742-orbit.jpg

Robert Zebahl
102mm f/11, 62x, Bortle 6, SQM-L 19.3, Seeing 2/5
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!
120mm f/5, 48x, Bortle 6, SQM-L 19.2
Nice, evident double near Messier 1. Easy to split with almost equally bright components.
152mm f/5.9, 69x, Bortle 6, SQM-L 19.3, Seeing 2/5
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.
8" f/6, 80x, Bortle 4-, SQM-L 20.8
Nice double star with nearly equally bright components.

STF 749 (**)
Name: STF749
Type: **
Constellation: Tau
Coordinates: 05h37m08.84s / +26°55'28.30"

Components:
m1 m2 ρ θ Year
AB 6m5 6m5 1.1" 319° 2017
AC 6m5 10m5 181.6" 299° 2011

../images/binary-star-orbits/STF749-AB-orbit.jpg

Robert Zebahl
70mm f/5.7, 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.

STFA 7 (**)
Name: STFA7
Type: **
Constellation: Tau
Coordinates: 03h31m03.47s / +27°43'53.60"

Components:
m1 m2 ρ θ Year
AB 7m4 7m8 44.1" 234° 2017
Robert Zebahl
120mm f/5, 18x, Bortle 6-, NELM 4m8+, SQM-L 19.1
Well split with noticeable difference in brightness. Nice view together with the double star STF401 located southeast.