A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Mike Freeman
Date: 2020 Oct 31, 11:25 -0700
Thank you Bob,
I have found a highly accurate triangle solver using your suggestion and at the same time re visited the measurements as follows..........
Earth centre to equator 6,378,137m (WGS84) Actual length of NM at equator 1842.9m
Assuming 1842.9m is 1 side of a triangle the angle at earth centre is 0.016555052428627 of a degree
Earth centre to pole 6,356,752.3m (WGS84) Actual length of NM at pole 1861.7m
Assuming 1861.7 is 1 side of a triangle the angle at the earth centre is 0.0167801965637 of a degree
1 minute is 0.01666666666 of a degree.
It is a pity I have to assume the figures for nautical miles are straight lines but it is best I can do.
This confirms my earlier suggestion that the NM at the pole subtended to the earth centre will create an angle at the earth centre greater than 1 minute and that the NM at the equator subtended to the earth centre will create an angle less than 1 minute.
Pleased to hear from anyone with any pearls of wisdom to add on this subject.