From: Peter Hakel
Date: 2021 Nov 26, 10:19 -0800
With thanks to Bill Ritchie, the author of Astron, I was able to correct an error in the SHA calculation of all stars in my spreadsheets. I had taken the official name of the parameter “Proper Motion in Right Ascension” too literally and, as a result, I was missing the division by the cosine of the declination in the SHA formula. This error was only really manifest for Rigil Kent. and for Polaris (due to the combined effects of their high proper motions and/or high declinations). I made the necessary correction for all stars, and the updated spreadsheets (aries_stars.xls, what_star.xls, polaris.xls, and polaris_lha.xls) were posted on:
Making the corresponding changes on the original Navigation Spreadsheets website turned out to be more complicated than in the past because the website provider had stopped supporting their original product. (I would have had to first port all its contents to a new website platform before I could make these changes.) As a result, I decided to close that website and domain; instead, I retain the WordPress blog:
containing examples, the GitHub download link posted above, and a presence on Facebook (as Navigation Spreadsheets, and Celestial navigation with Excel).