What are some alternatives?
When comparing Starmap and Space Engine, you can also consider the following products
Stellarium - Stellarium is a free open source planetarium for your computer.
Sky Map - Sky Map (formerly the Google Sky Map) turns your Android-powered mobile phone into a window on the...
Celestia - Celestia - real-time 3D visualization of space.
SkyView - SkyView is powerful, easy-to-use app that answers questions about stars, constellations, and more.
Solar System Scope - 3D model of the Solar System and night sky in real time
Star Chart - Stellarium is a planetarium software that shows exactly what you see when you look up at the stars. It's easy to use, and free. Read more about Star Chart.