Automatic pointing at stars.
When your device has a compass – iPhone 3GS, 4G or the iPad – Starmap uses the provided orientation, combined with the accelerometer to display map the portion of the sky you are looking at. First enable the compass action from the navigation settings. You can also enable and disable the compass from the main menu, touching the compass icon.
Hold the device in front of you, always perpendicular to your sight direction. You will see the map moving automatically, displaying what is «behind» your iPhone. In fact, Starmap will display what is a little above your iPhone … which is not transparent. So you will have the real sky, and just beneath, the exact map of the sky portion you are looking at. Turn around, move your head up, always holding the device perpendicular to your sight direction, and the map follows.