NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: ABC longitude calcs and PQR intercept calcs LOPS not lining up
From: David C
Date: 2026 Mar 20, 18:08 -0700
From: David C
Date: 2026 Mar 20, 18:08 -0700
This thread has sparked my interest and taught me something I did not know. Norie and Burton include the ABC tables but not Inman. Mr AI tells me the following:
- Norie's Nautical Tables are famous for including the "ABC Tables" (also known as A, B, and C Azimuth Tables) used to calculate the azimuth of a celestial body.
- Inman's Tables (originally by James Inman) are highly historical (19th/early 20th century) and known for their use of haversines and comprehensive nautical astronomy, but the widespread "A, B, and C" table format for azimuth calculation is usually associated with Norie's or later compilations like Burton's.
- While both publications contain tables to solve navigational triangles, "ABC tables" specifically for azimuths are a staple of Norie's.
File:
