NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Antoine Couëtte
Date: 2023 Nov 20, 13:15 -0800
Dear Peter,
Thanks for your feedback with numbers and for your Suwarrow Island picture.
From your Zeta Cap corrected altitude at 28d 22', I am guessing that your "raw" Altitude is 28d 27' ("raw", i.e. including Refraction and your 3' Dip).
Our updated fine-tuned Picture environment being :
S13°15'/W163°06.5' , on 01 Jan 2019, HoE = 9.5 ft, T = +25°C, P=29.92 "Hg, working backwards from your feedback numbers we get :
(1) - From Peacock - Alnair Position Angle at 20.045° , we get : Picture UT#1 = 05h56m04s
(2) - From Peacock - Zeta Cap Position Angle at 64.55°, we get : Picture UT#2 = 05h55m43s
(3) - From Zeta Cap corrected Altitude at 28d 22', hence Zeta Cap raw Altitude at 28°27' we get : Picture UT#3 = 05h55m36s
(4) - From Alnair raw Altitude at 33°57' we get : Picture UT#4 = 05h55m50s
(5) - From Peacock raw Altitude at 16°49' we get : Picture UT#5 = 05h55m41s
which yields an average value at 05h55m47s.
Aa a confirmation to our last provisional results, your measurements indicate that the Picture was taken at 05h56m with an error bar almost certainly inferior to 3 min and possibly inferior to 1 min,
FINAL RESULT : Picture UT = 05h56m +/ 2 min
(not far from earlier initial determination).
Thanks again to you both, Frank and Peter,
Kermit