NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Dave Walden
Date: 2010 Mar 31, 16:39 -0700
I used an excel spread sheet to carry out the LD calculations. I set up GHA, Dec, SD, etc. as functions of time using linear interpolation between 3 hour values from the JPL Horizons web site, as well as lat and long. (an aside, JPL gives CT-UT of 15.598 sec) Set up equations for apparent altitude of moon and sun and LD. Then find UT, lat, and long that minimizes RMS difference between observed and calculated. (Actually get UT, lat, and long that drives RMS to essentially zero!) Attached shows my values of lat plotted vs height of eye with Antoine's; agreement to a mile or so. As said, variation likely due to refraction model differences. (Also, just to get going quicker, I neglected flattening and oblateness.)
On to "Omahareno" harbour!
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