NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Meridional Parts
From: Lars Bergman
Date: 2024 Dec 21, 03:40 -0800
From: Lars Bergman
Date: 2024 Dec 21, 03:40 -0800
David C, for a latitude of 10°, I get the meridional parts equal 603.070' for the sphere. Are you sure that the Smithsonian document from 1909 and Norie from 1918 really shows 603.7'?
To extend your list I can add
- Roswall 1824: 603.1 (sphere)
- Bowditch 1851: 603 (sphere)
- Pettersson 1861: 599.1 (1/300 flattening)
- af Klint 1895: 599.0 (1/294.26 flattening)
- Korsström 1922: 603.1 (sphere)
These numbers all agree with the formula
MP(in radians) = arctanh(sin(lat)) - e·arctanh(e·sin(lat)), where e = sqroot(f·(2-f)) and f is the flattening.
Lars
