Tables for Azimuths, Great-circle Sailing, and Reduction to the Meridian, with a New and Improved "Sumner" Method: Latitudes 90° N. to 90° S., Declinations 90° N. to 90° S.: Also Other Useful Navigational Tables, with Numerous Examples of Double Altitudes, Equal Altitudes, Azimuths, Etc
Harold S. Blackburne
Free