NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Motion Correction for Longitude: sights around Noon
From: Bela Kovacs
Date: 2025 Mar 2, 07:08 -0800
From: Bela Kovacs
Date: 2025 Mar 2, 07:08 -0800
Dear Robert VanderPol II,
There was a thread about Noon sights:
https://navlist.net/find/Compare-Methods:-Lat/Lon-Near-Noon-from-date-200001-to-date-202512
Here is a detailed pdf:
https://navlist.net/m2.aspx/Compare-Methods-LatLon-Near-Noon-Cou%C3%ABtte-oct-2021-g51214
Here is the formula:
(Sn - d) * (tan(Lat) - tan(Dec)) * 48 / PI
Sn: the North-South component of vessel movement (knots)
Sn = speed * cos(course)
d: the change in declination of the Sun per hour (arcminutes)
Original article:
https://navlist.net/imgx/v32n1-6.pdf
A detailed explanation:
https://navlist.net/Noon-Fix-Wilson-jul-2009-g9074
I have attached a table, which I generated based on the formula above (same layout as in the Schlereth book).
Bela
