Most (60% or more) of the stars in our galaxy are members of multiple star systems, that is, two or more stars gravitationally bound into orbits around each other.

Click on one the links below to find more information on exactly what binary stars are.

Wikipedia should be normally be used with great caution but this article is really quite good, if lengthy. It will introduce you to binary stars and one of the themes of this page, eclipsing binaries, that is, stars whose orbits cause them to pass in front of each other as seen from the earh.

This location is a great simulation of a binary system. You can modify any of the parameters you want and watch how the appearance of the binary system changes as viewed from the Earth. Click on the instructions at the top of the screen if you need help.

More movies of binary systems are also available.

This is the place to go to learn about making observations of eclipsing binaries. All of the stars in this program are observable in amateur telescopes. Some of the fainter ones may require scopes in the 10 to 14 inch range, by far the majority can be observed in smallar telescopes, some are bright enough that their eclipses can be followed in binoculars, and one or two are naked eye eclipsers!
The AAVSO (American Assocation of Variable Star Observers) is the premier organization in the world receiving observations from amateurs (mainly) and making this data available to professional astronomers or other interested parties.
The BAA (British Astronomical Association) Eclipsing Binary Programme serves the same function in the United Kingdom.

Some representative samples of EB runs are shown below. All observations on this page are mine (Bob Manske).
Click on a picture to view the full sized image.
The brightness scale on the left is assigned by the software. The time hacks on the bottom scale are in ten thousandths of a day. The interval between hacks is just about 30 minutes unless otherwise noted.

CCD observed eclipse of AD Boo (2004 July 11)

CCD observed eclipse of CL Aur (2004 Nov 18)

CCD observed eclipse of OO Aql (2004 July 11)
Time interval is about 15 minutes

CCD observed eclipse of TW Cet (2003 Oct 19)
Time interval is about 15 minutes

CCD observed eclipse of U Peg (2004 July 11)
Time interval is about 15 minutes

CCD observed eclipse of UX Her (2004 July 11)

CCD observed eclipse of Y Cyg (2003 Oct 19)

This is not an eclipsing binary. It is an RR Lyrae type star, related to Cepheid variables. A very long observing run on this star.