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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: David Pike
Date: 2024 Aug 30, 01:53 -0700
As Promised: A PinA example. Being a gentleman of a certain age, I was forced to get up around 03.30UTC this morning. No, I didn’t go outside in my PJs with a sextant, but I did remember to take Frank Reeds GPS Spoof Moon values for 53.10N 000.32W at 03.50UTC.
I completed the calc this morning.
Yesterday I said, “You enter the table with height observed (or calc it hardly matters)”. Looking at the table, there can occasionally be occasions when it does matter. E.G. this very case. Should PinA be +50' or +51'? I was unable to find in the notes to the Air Almanac which is preferred. I bet Gary knows. As the Air Almanac is produced mainly for pre-calculation, I’m guessing that you should use basic Hc from HO249.
If you do pre-calculate as I have done (somewhat belatedly in this case), you need to change the sign of the PinA and the refraction values. DaveP
