NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: How to calculate daily advance of GHA Aries?
From: David Pike
Date: 2025 Aug 16, 13:58 -0700
From: David Pike
Date: 2025 Aug 16, 13:58 -0700
Using Frank’s approximation and Air Almanac 2024-25
From Air Almanac: 00.00.00UT 1/1/2025 GHA Aries = 100deg 54.0’
From Air Almanac: 00.00.00UT 1/1/2024 GHA Aries = 100deg 09.1’
Using approximation: 0.985648deg x 366days= 360.747168deg = 360deg 44.8’
Or GHA Aries 00.00.00UT 1/1/25 = 100deg 09.1’ + 360deg 44.8’ = 100deg 53.9’
I.e. 0.1’ out after one year. N.B. 2024 was a leap year. DaveP
