Civil Twilight Calculator

Everyone who works outside needs to know about daylight hours!
Pilots often need to know when night occurs. The FAA uses several different times of day for calling night vs. day, depending on the purpose.
Most Apps find the twilight times by going to a database on the internet. That means you need a network connection to use them.
This app is unique because it does all the celestial calculations internally! No internet required! Find the start of night at your destination while you are still in the air!
Lots of features:
Find sunrise and sunset at your current GPS location. Update sun calculations and sun dial every minute and every 10 km of movement.
Find sunrise and sunset at any airport in the world (The app has built-in coordinates for 11,000 airports around the world)
If you are connected (WiFi or Cell Data), you can look up the twilight times at any address in the world. Internet or cell access now also improves time zone accuracy.
The App calculates sunrise and sunset accurately forwards and backwards in time for 60 years.
The App calculates regular (standard) Sunrise/Sunset, Civil Twilight, Nautical Twilight, and Astronomical Twilight.
The App contains the relevant FAA regulations if you need a refresher!