What are some alternatives?
When comparing Starmap and Gaia Sky, 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...
Space Engine - Space Engine is a realistic virtual Universe you can explore on your computer.
SkyView - SkyView is powerful, easy-to-use app that answers questions about stars, constellations, and more.
KStars - KStars is a Desktop Planetarium for KDE.
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.