If you want to know which are stars and which are planets above you, use the Sky Map app to view the night sky. This app transforms your night sky into a detailed map of stars and planets right on your Android devices’ screen.
Star Tracker Lite - Night Sky Map for StarGazing by Shen Ji Pan
This is Google Sky Map, an Android app that allows you view a map of the sky through the camera of an Android phone. Once the camera is pointed towards the sky, Google Sky Map will then show the constellation and show information on it. The app uses GPS data, Compass data as well as date and time information to help identify the constellations.