Getting Started with the CelNav 360 app (Android version)

Celestial navigation exploits the principle that every measurement taken with a sextant (a `sight') converts to a line of position on a chart, the intersections of two or more such lines providing a position fix.

With the app you enter sights and inspect the resulting lines of position calculated for you under the hood.

It is possible to use your device camera in place of a sextant if you do not have one. See here