Tables of Computed Altitude and Azimuth: Latitudes 20 to 29

The National WWII Museum, 2015.498

After a navigator measured the angle to a star, being careful to note the exact time that he took the measurement, he consulted one of the many Hydrographic Office tables of computed altitude and azimuth. These tables gave the precise spot on the Earth above which that star could be found, from which a navigator could then determine his position at sea.