I would recommend that you consider any of the Skysafari 3 (about $3), Skysafari 3 Plus (about $16), or Skysafari Pro (about $41) options. If you go to Itunes you can look at the differences in numbers of stars and DSO's detailed between them.
Another reasonable app is the Starmap Pro.
If you simply wanna muck around with an astronomy app on the iphone, and not pay much or anything, then GoSkywatch and Stellarium are your best bets.
It may pay to simply buy an introductory star chart (such as The Sky & Telscope's Pocket Sky Atlas) instead and use it with additional cross referencing on internet astronomical sites.
I've tried many of them, and the Skysafari Pro was a good purchase for me, I use it a lot. I am missing a hard copy of a star chart, because you can't always rely on your phone app (battery charge, exposure to bright light wrecking your night adaptation when unlocking the home screen). The skysafari has a night mode where everything on the screen is red, preserving night vision, and you can set it to prevent auto lock to prevent the phone from going to sleep whilst this application is on, thereby avoiding glare from having to go through the unlock screen. One solution to this glare from the iphone app that I just thought of was a red coloured screen protector or even cellophane somehow tightened across its surface.
Regards,
Murat
I purchased it for my Ipad 2 a month ago when it was on special at around $30 and it's worth every cent IMO.
