Astronomy Software: Public Domain, Freeware, and Shareware

Stellarium astronomy software

Astronomy software, such as the free Stellarium program, can you help plan nights of observation. This frame shows Venus and the thin crescent Moon framing comet 2P/Encke.
Map: Bob King, Source: Stellarium

Dozens of free or inexpensive computer programs can aid your observing or simply allow you to explore the sky, with options available for Mac, PC, and Unix.

For those interested in exploration, take a look at the many planetarium programs on the market today. But that's only the beginning: there's astronomy software out there that can help you calculate information for lunar occultations, stack astrophotos, or solve the N-body problem.

Browse the list below to find software that suits your needs.

Directories of Astronomy Software

Planetarium, Sky Charting and Space Simulation

Lunar Observing

Other Observing Utilities

Optics and Equipment

Handheld computers

UNIX/Linux/X11

Physics and Astrophysics Software

Other Astronomy Software

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