SkySafari is described as 'powerful planetarium that fits in your pocket. It puts thousands of stars and planets at your fingertips. It lets you find objects in the sky using your device's built-in compass and accelerometer' and is an app in the Education & Reference category. There are more than 25 alternatives to SkySafari for a variety of platforms, including iPhone, iPad, Android, Android Tablet and Windows. The best alternative is Stellarium, which is both free and Open Source. Other great apps like SkySafari are Sky Map (Free, Open Source), Gaia Sky (Free, Open Source), KStars (Free, Open Source) and Sky Guide (Paid).
Vortex Planetarium - Discover the sky. The most comprehesive, fully featured Planetarium on Android. Used by amateur astronomers and armchair observers alike, Vortex Planetarium offers a window to the skies in stunning detail.
Planisphere is an astronomy application that lets you use pinch and finger gestures to manipulate a map of the sky. As you zoom in finer detail comes into view. You can double tap on objects to get more information.