What are some alternatives?
When comparing SkyORB and Vortex Planetarium, you can also consider the following products
Stellarium - Stellarium is a free open source planetarium for your computer.
KStars - KStars is a Desktop Planetarium for KDE.
Sky Map - Sky Map (formerly the Google Sky Map) turns your Android-powered mobile phone into a window on the...
Space Engine - Space Engine is a realistic virtual Universe you can explore on your computer.
Solar System Scope - 3D model of the Solar System and night sky in real time
SkyView - SkyView is powerful, easy-to-use app that answers questions about stars, constellations, and more.