NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Robin Stuart
Date: 2023 Mar 11, 05:23 -0800
Ed,
Rather than try to wrangle the problem in 3 dimensions I strongly suggest that you look at Bessel's method which dramtically simplifies things. After making an orthographic projection onto the plane perpendicular to the geocentric direction of the star (essentially the view of an observer on the star) the problem is reduced to 2 dimensions involving just circles and points on a plane. There is no need to separately consider parallax or the Moon's apparent semi-dameter. Here for example is a figure that I made to explain my observation of the occultation of ξ2 Ceti on 18 December, 2018. I'm the red dot. The star's geographic position is indicated. Because of the orthographic projection the Earth and the Moon are represented by their true relative sizes. One other thing I should point out. For occulations it's not enough to treat the Earth as a sphere. The figure of the Earth needs to be taken into account. This is also neatly incorporated into Bessel's method,
Regards,
Robin
