I have 40 years programming experience but I am new to phones. I run Linux on my PC and have programmed in 11 different languages. But I am clueless about all this stuff with phones. I want to create an App or encourage someone else to create an App to use the phone as a Sextant. Yes, I know it has GPS. BUT what happens if you need to know where you are AND a huge sun generated EMP wipes out all the satellites? Ok, this thing has a compass, a clock, and a level function to measure vertical angles. That and a table of astronomical data is all you need. I can do it by measuring the angle with "Bubble" and then measuring the magnetic heading with "Compass" and then looking at the clock and then pulling out my pocket tables and a lot of math. But if it could all be combined into a function where I could sight over the edge of my phone at the star or Sun or Moon, then press the camera button and capture the angle, mag heading, and time all at the same time and then have all that go into the App which after I told it which astronomical body I was refering to, consulted a table on the SD card and then spit out the location....that would be really neat. That would be an app that didnt need phone service, satellites, or anything except a battery that was charged. Could be used by the last surviving human beings after a world wide disaster if they had the phone and a solar panel to charge it. The ultimate survival tool. Could navigate the world with it and some downloaded charts.