Astronomy Software: Public Domain, Freeware, and Shareware

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

• Sky & Telescope's BASIC Program Listings
• Hugo D. Valentim's Astro Tips
• Searchable shareware library
• Dan Bruton's Astronomy Software Listing
• Freeware Astronomy Downloads

Planetarium, Sky Charting and Space Simulation

• Cartes du Ciel by Patrick Chevalley (Win)
• Celestia by Chris Laurel (MacOS)
• C88 by Alcyone Software (Win)
• CoolSky by Piotr Czerski (Win)
• CyberSky by Stephen Schimpf (Win)
• Distant Suns by Mike Smithwick (Win)
• EquinoX by Microprojects (MacOS)
• HNSky by Han Kleijn (Win)
• Home Planet by John Walker (Win)
• JupSat95 by Gary Nugent (Win)
• Kagayaki IV by SeedsBox (Win)
• MacAstronomica by Artistic Techworks (MacOS)
• MyStars! by David Patte (Win)
• Night Sky by Kaweah Concepts (MacOS)
• Night Vision by Brian Simpson (OS/2)
• Planetary, Stellar and Lunar Visibility by Alcyone Software (Win)
• Power Age Sky Simulator by George Dragandjikov (Win)
• Stargazer's Delight by Kaweah Concepts (MacOS)
• StarStrider by FMJ-Software (Win)
• sofTouch APpLications's MOONCLOCK, ASTROCAL, and others (MacOS)
• Spica by Richard Guillaume (Win)
• Stellarium by Fabien Chéreau (Win/MacOS/Linux)

Lunar Observing

• LunarPhase by Gary Nugent (Win)
• Virtual Moon Atlas by Patrick Chevalley and Christian Legrand (Win)
• MoonCalc by Monzur Ahmed (Win)
• MoonMenu by Selznick Scientific Software (Win/Mac OS)

Other Observing Utilities

• Astronomer's Digital Clock by Matt Oltersdorf (Win)
• AstroPlanner by iLanga, Inc. (Win/MacOS)
• DarkAdapted by Stephen Hutson (Mac OS)
• David Paul Green's Free Astronomy Software: The Simple Observing Log, The Eyepiece Calculator, and others (MacOS)
• Lunar Occultation Workbench by Dutch Occultation Association (Win)
• MAXCLOCK by Udo Mark (Win)
• Varobs by Patrick Chevalley (Win)

Optics and Equipment

• Aberrator and Registax by Cor Berrevoets (Win)
• Basic Newtonian Telescope Calculator by Dave Richardson (DOS)
• Image Stacker and AstroImager by Keith Wiley (MacOS)
• Modern Optical Design and Analysis Software by Ivan Krastev (Win)

Handheld computers

• AstroMist by Cyrille Thieullet (Palm)
• AstroPhoto and MessierLog by John Biondo (Palm)
• Lunar, Orrery, and Jovian by Astro-Metrics (Palm)
• Planetarium by AHo (Palm)
• Planisphere by Check-Tech Software (Palm)
• PleiadAtlas by Brian Tung (Palm)
• Pocket Stars by Nomad Electronics (Pocket PC)

UNIX/Linux/X11

• European Southern Observatory's Scisoft compilations
• Image Reduction and Analysis Facility (IRAF)
• ESO-MIDAS
• FTOOLS
• Hitchhiker by Aaron Worley
• Light Speed by Daniel Richard G.
• Nightfall by Rainer Wichmann
• SAOimage
• Xephem by Elwood Downey

Physics and Astrophysics Software

• AstroGrav by AstroGrav Astronomy Software (Win/MacOS)
• Cavendish by Benjamin Blonder (Win / MacOS / Unix)
• Gravitation 3D by Roice Nelson (Win)
• Newton's Aquarium by Living Graphs(Win/MacOS)
• Orbit Xplorer by OttiSoft (Win)

Other Astronomy Software

• Astro Utilities Electronic Book for Mathcad
• Halo3 by Les Cowley and Michael Schroeder (Win)
• PCs in Space by Jackson and Tulls (Win)
• Shadows by François Blateyron (Win)
• Solscape by StimpSoft (MacOS)
• Space Telescope Science Institute's Electronic PictureBooks (Win/Mac OS)
• TRAKSAT and WinTrak by Paul Traufler (Win)
• Urania for Hewlett-Packard pocket calculators by Georg Zotti