Gaia Sky is a real-time, 3D, astronomy visualisation software
Cyril
A free astronomical image processing software
Marmer
Marmer ass e virtuelle Globbe a Welt atlas - Är Schwäizer Arméi Messer fir Maueren déi Dir benotze kënnt fir méi iwwer d'Äerd an aner Planéiten ze léieren.
Stellarium
Stellarium is a free open source planetarium for your computer.
KStars
KStars is a Desktop Planetarium by KDE. It provides an accurate graphical simulation of the night sky, from any location on Earth, at any date and time.
Celestia
Celestia – real-time 3D visualization of space