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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: David Pike
Date: 2023 Nov 23, 06:27 -0800
First a correction to a typo in my last post, which I've only just noticed.
For: Then do the same but starting from 59.9°N, and use cos 59.5° and cos 60.1°N, and not the difference in ch-longs.
Read: Then do the same but starting from 59.9°N, and use cos 59.5° and cos 60.5°N, and note the difference in ch-longs.
I did the maths, but waited to see if anyone else would try it. It's a good job they didn't, because of my typo.
Anyway, attached is my calculation of the effect of the differences in ch-longs using either start or end latitudes for a start at around 10°N and 60°N. I didn’t bother with a middle latitude. Without getting into the exact shape of the Earth, the choice of latitude used seems insignificant at low latitudes, but it begins to become significant at higher latitudes. DaveP
