Iphone Astronomy Hak
Brian @ Hackszine writes –

NightLight wrote in with a request for a red overlay to “use your iphone in the dark but keep your night vision.” I was reminded of the hacks about using red film in Astronomy Hacks: put it over your PDA or notebook computer, and you are all set. But to try it out, I needed to find an astronomy site that works well on the iPhone. Many online planetariums use Java to do their thing, but Your Sky is a great web site that does a couple of things simply and quite well: you can punch in your latitude and longitude, and you get a view of exactly what’s above you at the moment. You can tap to zoom in, and you can pan around. Just what I needed. (To save a little time, figure out your latitude and longitude on your Mac, save a bookmark for your Your Sky page in Safari, and sync your bookmarks to your iPhone so you can get to the star chart quickly.)

Use your iPhone as a stargazing companion – Link.