A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Position-Finding
From: Lars Bergman
Date: 2018 Mar 10, 12:45 -0800
Attached an alternative solution, without calculator and without plotting, based on "cloudy weather" Johnson's method. By skipping the tenth of minutes four figure logs are generally sufficient, hence no need to interpolate in the log table. By choosing an integer degree value of latitude, interpolation work in ABC-tables are reduced; however I added one minute to avoid half minutes in the half-sum. In many nautical tables (from the time-sight period) there is a table of "correction to longitude for 1' error in latitude" that is equal to Johnson's table.
Lars 59N 18E