NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: David Pike
Date: 2021 Feb 11, 14:59 -0800
It’s true folks. The Sun really was running 14 minutes 12.6 seconds slow today. Well, I measured 14 minutes 22 seconds with a battered old RAF Mk 2C peri-sextant through the bedroom window (closed naturally at 0 C outside), but who’s going to argue over nine seconds? I took 24 instantaneous shots from one hour before to one hour after the anticipated time of real noon. I kept Frank Reed’s GPS Spoof app running on my smartphone to check my combined index and aiming error at the same time, but I used my own shots for the test. I plotted height sextant above 21 degrees Hs on the Y axis and minutes after 11.16UTC on the X axis to get a nice big graph. Then I put up a blank WORD page up on my PC; folded my graph in two; and wiggled it around on my PC screen to match up the sides of my graph. Real noon at 000.32W came out as 60.5 minutes after 11.16. Then I corrected for motion of the body to get real noon at Greenwich as 1214 and 22 seconds UTC. DaveP