Stellarium is a free open source planetarium for your computer. It is a free and open source sky rending application that's fun and comprehensive.
Here are some screenshots to illustrate the features and user interface of this application:
Fill out information to examine specific objects. Screenshot of Stellarium - 670px · 501pxExamine past constellations easily. Screenshot of Stellarium - 670px · 503pxShow or hide specific objects. Screenshot of Stellarium - 670px · 503pxResort to handy tools. Screenshot of Stellarium - 670px · 503pxLearn about planets and Universe in 3D. Screenshot of Stellarium - 670px · 501pxSee stars, planets and nebulae in real time. Screenshot of Stellarium - 670px · 501px
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