This app demonstrates in a simple way how to determine Latitude, Longitude, Ship Point, simply using Sun, Sextant and Height Lines.- Celestial sphere and terrestrial sphere, illustrated with all the components useful for understanding astronomical navigation, description and operating principle of the sextant.- Variation of the declination of the Sun over the course of the year with interactive graph to identify the variation of the LHA (Local Hour Angle) as a function of the GHA (Greenwich Hour Angle).- 3 concrete examples to determine Latitude, Longitude and Height lines explained through 3 animations on different nautical charts showing the various uses of the height lines.- 2 downloadable neutral calculation grids, to be used for practical exercises.Ephemeris and H.O. tables 249 used in all the examples given in the text.