A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Tony Oz
Date: 2019 Nov 12, 01:29 -0800
Dear Frank, you are absolutely correct on all the points here.
Some background on what I try to do.
I was asked by a friend to update a ~30-years-old article explaining the ways a programmable pocket calculator may be used on board of a yacht. The particular calculator involved (the Electronika MK-52) is VERY limited in resources, all sorts of programming wizardry was used to cram something useful into its' tiny memory.
The most interesting part of my attempt is centered on calculation of the ephemeris coefficients (Sun's and FPoA') for the current year and several next ones. The algorithm depends on a triplet of coefficients which must be used in each year accordingly. The article gave the table of those coefficients for 1989~1993 only and no explanation of how to obtain them for the future. The program expects the day number since the Jan-0th of the year in question and the value of UT.
I've managed to decipher the RPN code of the formulas and now I have an idea how to create an updated table of coefficients - the ephemeris code is similar to the long-term almanac given in the Henning Umland's book (Chapter 15).
If somebody is interested - I can post my results here too.
So, I'm not about the ways to calculate azimuths not knowing the altitudes, I just did not recognise the well-known formula in its' RPN disguise.