Do you want to have a planetarium in your computer? Stellarium is an open source 3 dimensional desktop planetarium for Windows, Linux/Unix and Mac OS X. It can display a realistic sky on your desktop. So without going out and without using a binocular or a telescope you can easily look at the stars sitting before your computer.
Stellarium renders the sky in realtime with OpenGL. Stellarium is very easy to use. All you have to do is set the coordinates and watch the sky. You can get useful information about the brightest stars, planets and others. There is a zoom mode which lets you see the sky more clearly. The default catalogue has information of more than 600,000 stars and some extra information about 210 million stars.
You can see information about constellations, Milky Way and nebulae. You can also see the realistic sunrise, atmosphere and sunset. you can now have the eclipse simulation also. You can also add your own Landscapes, Constellation Images and Sky Objects.
Stellarium is available for Linux, Mac OS X and Windows.