http://itunes.apple.com/us/app/astro...8395?ls=1&mt=8
AstroAid is a universal app for iOS devices running iOS 5.0 or later*. It functions as an aid to visualising what you will see through your telescope when you use a particular eyepiece and, optionally, an optical aid (such as a Barlow lens). Additionally you can pair an imaging device (imager or camera) with a telescope or camera lens and show the field of the imager overlaid on the sky. The ability to drag and rotate the imager field will help with imaging session planning.
The app computes a number of parameters for your telescope/eyepiece/imager combination, such as magnification, actual field of view, visual magnitude limit, etc. and displays these values in tabular form.
Additionally, the application contains images of the 110 Messier objects and will show you what these objects would look like through the eyepiece (by suitably scaling the images). The app also contains the NGC, IC and Caldwell catalogues, and the ability to download similar images conveniently via the Internet.
The app contains extensive lists of known vendor-supplied telescopes, camera lenses, eyepieces, imagers, and optical aids. You can also create your own custom entries if your equipment isn't listed (for example, if you made your own telescope).
A complete manual is available on the support page at:
http://www.ilanga.com/astroaid
AstroAid is (currently) priced at US$2.99.
* This implies that the app will run on: the iPhone 3GS or later, the iPod Touch 3rd generation or later, and all versions of the iPad. Sorry, the app is not available for Android or Windows.
