A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Brad Morris
Date: 2015 Nov 12, 11:49 -0500
Did you use HO 203/204 in 1946 or have you reworked the problem using that data merely as an example?
There is an errata insert pasted into my 1923 HO203 volume which clearly corrects the errors found in the explanation (or to use the 1800's term...explication) of the tables. I've attached the front piece of that insert, dated 1924. So the errors were found quickly, within a year of first issue.
The 1933 HO204 contains no such errata.
There is yet another paper glued into the 1923 volume, "Additional Uses of HO 203", to wit: Star Identification as well as Determination of Morning and Evening Twilight. Attached.
Specifically referenced in the production of HO203 are the following works
(1) Abrégé de Navigation, historique, théoretique, et pratique.... Jerome Lalande. Paris 1793
(2) Horary tables for finding the time by inspection, to facilitate the operations for obtaining the longitude at sea, by chronometers and lunar observations... Thomas Lynn. London 1827
(3) Azimuth tables showing the true bearing of the sun... Thomas Lynn. London 1829.