Nautical Astronomy is a free Android app that provides a comprehensive guide to celestial navigation or astronavigation. Developed by Navigational Algorithms, this app allows you to calculate your latitude using the old methods of astronomical navigation. With Nautical Astronomy, you can take the sextant and shoot the Sun or the North Star, and let the app do the calculations for you.

The app offers five different methods to calculate your latitude: Latitude by Polaris, Latitude by Noon sight, Latitude by Sun ex-meridian sight, Latitude by the Sun's Altitude and Time, and Time sight for the Sun. To use the app, simply tap on Date, Time, DR, Hs, and sight parameters to enter the data, choose the calculation in the combobox, and push [Calculate] to get the solution.

Nautical Astronomy also features a Location setting for training purposes, which allows you to set your position using Google Maps, GNSS fix, or an input dialog box. The app requires Location and Storage permissions to function properly. You can also find a manual and examples on the developer's website.