NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: David Pike
Date: 2023 Aug 17, 08:31 -0700
On our way out to Zephyr yesterday, it was such a lovely sunny day I decided to take the chance of the Sun line I promised with the Mk2a, as I wasn’t sure when I’d get another chance. By the time I’d got set up, I recorded the first shot at 09hrs 23min 23secs. This was part of the plan, because I wanted to show full use of the form. I didn’t assume I was at altitude travelling at high speed, just stationary on the ground. I didn’t even run the sextant (but you do need to wind it up to get it to light up). Why bother when there’s no acceleration error. You’ve seen those bits during the 7 Shot Fix. I recorded further shots at 09.26.23 and 09.29.23.
For my calcs I used the USAF Air Almanac 2023 and AP3270 Vol 2 known as “the yellow band” (HO249) liberated from Vulcan XM603. The sextant was last calibrated properly on 29th January 1998 by Fenns of Farnborough over 25 years ago, but it was probably put straight into store and the box never opened since. The resulting line is rather impressive for an aircraft sextant and better than any of my other Mk2s. If yours is that good when it arrives, you’ll have a bargain. Don’t worry if there’re no spare 3v bulbs in the box. They hardly ever break. If one does, you’ll certainly find two spares pushed into the side of the sextant. DaveP
