Google Sky Maps - Android apps

Google Sky Maps 

Free

A virtual planetarium at your fingertips, Google Sky Maps may be the coolest app in the Market. Using GPS and the accelerometer and compass, it displays a live map of the sky where you are. Hold up the phone as if taking a picture, and Sky Maps shows the portion of the heavens directly behind, like an overlay on reality.

Can't figure out a constellation? Point the phone at it, and Sky Maps will show you. Wondering if a body is a star or a planet? Sky Maps will identify it. The app occasionally gets confused when it can't tell if the phone is horizontal or vertical (such as when you're holding it flat to point straight up), and sometimes draws the lines in constellations a bit wrong. But overall, it's a marvel.  

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