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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Moonrise over Connecticut, 19 October 2021
From: Sean C
Date: 2021 Oct 29, 20:38 -0700
From: Sean C
Date: 2021 Oct 29, 20:38 -0700
Antoine,
I believe you are correct. I had been meaning to reply earlier, but your posts had me fiddling with my own spreadsheet almanac.
When I read your earlier post about the Sun and Moon being 2.0' above the horizon, I compared my results with Frank's [USNO's] and they were nearly identical. I am using Meeus' formulas, but I am indeed simply calculating all corrections for Hc and subtracting them out to get Ha. But, as you pointed out, this really only has a noticable effect at very low altitudes. This is why I never even bothered to check those cases. However, I think I just might go ahead and correct that for the sake of accuracy.
Regards,
Sean C
