A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Murray Peake
Date: 2018 Jan 9, 12:38 -0800
I've been looking around for a good method of calculating longitude from the occultation of stars. The only one I've found so far (that I can understand...) is in Chauvenet Vol1, p551.
I've recomputed his example for Cambridge, Mass April 15, 1856 using a modern ephemeris - it works out pretty well but if you start with a poor guess for longitude (say 75 degrees instead of the MICA value of W 71°07'48.0"), it takes around 15 iterations to converge.
I've looked at Bowditch, Inman and Raper but reverse engineering their recipes looks like a last resort. Can anyone point me at anything more understandable.
One day I hope to see an occultation - at the moment I'd be happy to see a star... The weather here in Brittany is a bit murky.