StarLight Pro
• StarLight Pro produces animated views of eclipsing binary stars and calculate synthetic lightcurves. The effects of limb darkening, temperature, inclination, stellar size, mass ratio, and star shape are included. This is a free download for Windows.
• Binary View
  • Windows software provided by Alexander Hobbs at Leicester University, UK.
• JAVA Simulations of Binary Stars
  • JAVA Example from Cornell University.
• Eclipsing Binary Simulator
  • EBS is a Windows astronomy application to visualise the orbit and synthetic light curve of binary star systems. It is made for educational purposes and for having fun.
• Binary Stars
  • Free astronomical software for Macintosh computers, complete with manuals, teaching binary star concepts, for classroom or personal use.
• Nightfall Eclipsing Binary Star Program
  • Nightfall can produce animated views of eclipsing binary stars, calculate synthetic lightcurves and radial velocity curves, and eventually determine the best-fit model for a given set of observational data of an eclipsing binary star system. (Linux or Unix)
• Wilson-Devinney Code
  • Fortran code provided by Robert E. Wilson a the University of Florida.
• PHOEBE
  • PHOEBE stands for PHysics Of Eclipsing Binaries. It is an astronomical software that helps you do the modeling of eclipsing binaries (EBs) based on real photometric and spectroscopic (radial velocity) data. It is based on the Wilson-Devinney code. (Linux or Unix)
• Binary Maker
  • Commercial software by Contact Software.
• FindEB
  • Macintosh programs by Dr. Claud H Sandberg Lacy (clacy@uafsysb.uark.edu) at the University of Arkansas.
• BASIC Programs from Sky & Telescope
  • BASIC code for modeling binary stars: BINARY.BAS, GOSS.BAS, PULSAR.BAS, PERIOD.BAS
  SEDS
  • This is a collection of 5 archived programs related to binary stars.
• Phases
  • Fanel Donea's DOS program that computes heliocentric phases.

• General Catalogue of Variable Stars: [ SFA Excel | Site 1 | Site 2 | Site 3 ] - Type Key
• An Atlas of O-C Diagrams of Eclipsing Binary Stars
• Stars from Binary Stars: A Pictorial Atlas
• Eighth Catalogue of the Orbital Elements of Spectroscopic Binary Systems
• AAVSO - Eclipsing Binary Section
• Catalogue of Algol-type Binary Stars

Online Articles and More Information

• Photometry of 68 Herculis
• Watching Beta Lyrae Evolve
• First Resolved Images of the Eclipsing and Interacting Binary ß Lyrae
• Photometry of Algol and Beta Lyrae
• Hipparcos: Folded Light Curves
• Southwest Research Institute Articles
• Eric's World of Astronomy
• Astronomy Picture of the Day
• "Most Stars are Binary Stars"
• IBVS - Information Bulletin on Variable Stars
• IAPPP - International Amateur-Professional Photoelectric Photometry
• AAVSO - American Association of Variable Star Observers
• SIMBAD Astronomical Database or US Mirror
• Eclipsing Binaries Minima Database

What are Binary Stars?

One can classify binary stars based on their appearance from earth. Stars that are far enough apart to be distinguished from each other are known as visual binaries. Other binaries are too close and far away to be seen separately but can distinguished using the doppler shift of their spectra. These are spectroscopic binaries.

In rare instances, such as with the star Algol the binary stars are close enough so that the eclipse one another. In this case, one can calculate not only the mass of the binary star systems, but also the radii of the stars.

Visual Binaries and Optical Doubles

• Optical Doubles from an S&T Article - Excel File
  Hanwell Community Observatory - Double Stars
• Double Stars for Seeing Estimates
• StarGazer Double Star List
• Washington Double Star Catalog
• Brightest Double Stars
• 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
• 85 Interesting Double Stars and 22 Interesting Varible Stars
• Astrophotos of Binaries
• Royal Observatory of Belgium
• Observing Doubles: The Spirit of 33
• Double Star Observer
• Webb Society Double Star Section
• Dynamics & Astrometry: Double & Multiple Stars
• La Commission des Etoiles Doubles, Société Astronomique de France
• Amazon Books - Search for "Binary Stars", "Double Stars", etc.
  • Binary Stars: A Pictorial Atlas
• Double Star Library
• Third Interferometric Catalog
• Fourth Interferometric Catalog
• Fifth Orbit Catalog
• Sky & Telescope's Double Star Lists

COMMON DOUBLE STARS WITH SIGNIFICANT COLOR CONTRAST 
(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 
******************************************************************** 
 
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.