Satellite look angle calculations

Having spent a few months searching in vain for a good source of information on satellite look angles, I finally managed to get what I needed from a friend of mine who works for NSSL Global, a small satcoms company.

I then spent a couple of days integrating the mathematics into a simple app:

The app is available here, it's free, supported by advertising provided by admob. As of today, it's been downloaded a grand total of 14 times (2 of which are by me). Advertising revenue is, as you'd expect,  pretty pathetic, but the main aim behind uploading to the market is to get some feedback regarding the accuracy of the calculations. I have tested them against various online calculators, including dishpointer, and they do seem to be correct, but I'm hoping that if there is any errors in there, they'll be picked up by people who are actively involved in satcoms.