NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Skyfield
From: John D. Howard
Date: 2018 Oct 23, 09:05 -0700
From: John D. Howard
Date: 2018 Oct 23, 09:05 -0700
Lars,
I think you and many others think of the Nautical Almanac as a refrence book for accurate astronomical positions. It is not.
The NA is printed to be used by navigators at sea using a hand held sextant. It has deliberately, built in errors of up to 0.15 m or 9 seconds of arc. Errors of up to 0.25 m or 15 seconds of arc in GHA or Dec are built in.
Compare Skyfield to MICA - I think the data will be closer.
John H. 41N 100W
