Binary Stars is a free astronomy software for Macintosh computers, complete with manuals. It teaches binary star concepts. It may be used in a classroom or lab setting, or for self-education.

You have been granted the powers of a god -- complete control of your own personal binary star. Six panels display everything you ever wanted to know about a binary star: overhead view, view from the Earth with a super-gigantic telescope, light curve, radial-velocity curve, Hertzsprung-Russel diagram, and mass-radius plot. Animate the figures. Change the values of the parameters and immediately see the effects on every aspect of your binary star. Try fitting the parameters to simple practice data sets, then when youre ready, try out some real eclipsing binaries (10 real binaries are provided).