A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Ron Jones
Date: 2019 Feb 20, 09:57 -0800
Tony Oz on Date: 2019 Feb 20, 00:38 -0800 wrote:
“You must realise that the mentioned ±0.5° uncertainty would get into the time thus calculated - most probably - with some VERY significant multiplicand. The GMT thus obtained will be very unreliable.”
Yes the calculated UT Based on the equation, shown below, Is a lot more sensitive to COS(delta_Zn) than I first realized. :
GLD = COS-1[SIN(HoBody)•SIN(HoMoon) + COS(HoBody)•COS(HoMoon)•COS(ZnBody-ZnMoon)]
In the example I used the exact values for Ho & Zn produced a calculated UT of 11:19:15 which was only one second slow of the exact UT of 11:19:16. When the delta_Zn was increased by 1° the calculated UT was 10:07:27 & when the delta_Zn was decreased by 1° the calculated UT was 12:29:15.