A visual binary star is a binary star for which the angular separation between the two components is great enough to permit them to be observed as a double star in a telescope, or even high-powered binoculars.
Visual Binaries and Optical Doubles
- Optical Doubles from an S&T Article - Excel File
- Washington Double Star Catalog
- The Orbits of 150 Visual Binaries
- Welcome to the Visual Binaries
- The Orbital Elements of Selected Visual Binaries
- 33 Doubles in Orion
- Astronomical League Double Star Club
- Astronomical League Double Star Observing List
- Royal Observatory of Belgium
- Dynamics & Astrometry: Double & Multiple Stars
- La Commission des Etoiles Doubles, Société Astronomique de France
- Double Star Library
- Third Interferometric Catalog
- Fourth Interferometric Catalog
- Fifth Catalog of Orbits of Visual Binary Stars
- Sky & Telescope's Double Star Lists
Colorful Binary Stars
The list below contains a common visual binary stars with significant color contrast.-
Eta Cassiopeiae, R.A. 0h 49.10m Dec. +57d 49.0'
Primary: mag. 3.4, sp. G0V, Secondary: mag. 7.5, sp. dM0
Sep. 12.8" arc, P.A. 317 deg. (period: 480 years)
Colors seen in 10 inch: Off-white and faint reddish-orange.
- ALMACH (Gamma And.), R.A. 2h 3.90m Dec. +42d 19.8'
Primary: mag. 2.2 sp. K3III, Secondary: mag. 4.8 sp. B8V
Sep. 9.8" arc, P.A. 64 deg. (mag. 6.3 companion of Gamma-B at 0.4" arc,
p.a. 103 deg.).
Colors seen in 10 inch: Yellow (Gold) and light blue.
- h3945 (ADS 5951, CMa), R.A. 7h 16.61m Dec. -23d 18.9'
Primary: mag. 4.8 sp. K4III, Secondary: mag. 6.8, sp. F0
Sep. 26.6" arc, P.A. 55 deg.
Colors seen in 10 inch: Orange and bluish-white.
- Iota Cancri, R.A. 8h 46.70m Dec. +28d 45.6'
Primary: mag. 4.0 sp. G8II, Secondary: mag. 6.6 sp. A3V
Sep. 30.5" arc, P.A. 307 deg.
Colors seen in 10 inch: Light yellow and pale blue.
- 24 Comae Berenices, R.A. 12h 35.13m Dec. +18d 22.6'
Primary: mag. 5.0 sp. K2III, Secondary: mag. 6.6 sp. A7V
Sep. 20.3" arc, P.A. 271 deg.
Colors seen in 10 inch: Yellow and pale blue.
- Izar (Epsilon Bootis), R.A. 14h 44.99m Dec. +27d 4.5'
Primary: mag. 2.4 sp. K0II, Secondary: mag. 5.1, sp. A2V
Sep. 2.8: arc P.A. 339 deg.
Colors seen in 10 inch: Yellow and light blue.
- Antares (Alpha Sco). R.A. 16h 29.41m Dec. -26d 25.9'
Primary: mag. 1.0v sp. M1I, Secondary: mag. 5.4 sp. B4
Sep. 2.6" arc P.A. 274 deg.
Colors seen in 10 inch: Orange and light blue.
- Ras Algethi (Alpha Her) R.A. 17h 14.65m Dec. +14d 23.4'
Primary: mag. 3.2v sp. M5II Secondary: mag. 5.4, sp. F2/G3
Sep. 4.6" arc P.A. 104 deg.
Colors seen in 10 inch: Reddish-orange and pale bluish-white.
- SHJ 282 (ADS 11834, Lyra), R.A. 18h 54.90m Dec. +33d 58.0'
Primary: mag. 6.1, sp. G8 Secondary: mag. 7.7, sp. A1
Sep. 45.4" arc P.A. 350 deg.
Colors seen in 10 inch: Yellowish-white and bluish-white.
- Alberio (Beta Cyg) 19h 30.72m Dec. +27d 57.6'
Primary: mag. 3.1 sp. K3II Secondary: mag. 5.1 sp. B8V
Sep. 34.3" arc P.A. 54 deg.
Colors seen in 10 inch: Yellow and light blue.
- ADS 12900 (Cyg). 19h 45.86m Dec. +35d 0.77'
Primary: mag. 6.1 sp. K2? Secondary: mag. 8.6 sp. A2V
Sep. 37.5" arc P.A. 25 deg.
Colors seen in 10 inch: Yellow and blue.
- Gamma Delphini, R.A. 20h 46.73m Dec. +16 deg. 7.8'
Primary: mag. 4.2 sp. K1, Secondary: mag. 5.2 sp. F8.
Sep. 9.6" arc P.A. 268 deg.
Colors seen in 10 inch: Yellowish and white (hint of blue)?
- Delta Cephei R.A. 22h 29.20m Dec. +58d 25'
Prmary: mag. 4.07 (variable) sp. F5-G3 Secondary: mag. 6.27 sp. B7
Sep. 40.8" arc P.A. 191 deg.
Colors seen in 10 inch: Yellowish-white and light blue.
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KEY:(positions, separations, and position angles for 2000)
LEGEND: R.A. = Right Ascension (2000.0) Dec. = Declination
mag. = apparent visual magnitude sp. = spectral type
Sep. = separation (in arc seconds) P.A. = position angle