Astronomy Software for Cheap (or Free!)
Imaging and Image Processing
Image Capture
K3CCD Tools is a fantastic program that works with many different cameras
Craterlet is a simple webcam capture program
PHD Guiding (for Push Here Dummy) is a very simple autoguiding program
WcCtrl keeps webcam controls visible
WcRmac allows you to modify webcam settings
Image Processing
Registax is the standard for stacking video
Avistack is a new alternative to Registax
Nebulosity stacks and processes many image formats
Star Charts
Cartes du Ciel ("Sky Charts" ) is fully functional charting software
Virtual Moon Atlas is an unbeatable companion for lunar viewing
Home Planet is an easy to use beginner's program
Planetarium Software
Stellarium is a general purpose program
WinStars lets you travel through the solar system
Celestia lets you travel anywhere - even outside the Milky Way!
Where is M13? helps you visualize where objects are in the galaxy
Universe Sandbox lets you simulate orbits, colliding galaxies, etc.
Observing Tools
Planet, Satellite, and Lunar Visibility builds charts showing when objects are visible during the year
JupSat95 is an old standard for tracking the Jovian moons
Satellite Tracker will track satellites and actually drive a telescope to keep them in view
Stellaris has a LOT of functionality for planning observing sessions
MoonPhase puts the current moon phase in your status bar
NightCal gives you complete information on the Moon, Venus, and Mercury
Geomagnetism is a tool for calculating the difference between true north and magnetic north
Other
World Wide Telescope is a great resource for seeing the sky in various wavelengths
GIMP is a full-functioned, free alternative to Photoshop
Orbiter lets you fly various spacecraft from launch to orbit and beyond
