NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Gary LaPook
Date: 2026 Sep 17, 17:21 -0700
Some of you will remember that several of us had the opportunity to take sun observations while in flight aboard a Cessna 172 way back in 2010. Well, last weekend, two of the original four had the opportunity to take observations of the sun through the standard astro-dome in a B-17, I had always wanted to do this and finally had the chance!. The other original navigator from 2010 was Greg Rudzinski, a very experienced marine navigator who also created a number of useful celestial tools that he shared on Navlist, and one of the most prolific posters from that era.
I took an observation of the center of the Sun with my A-10A bubble sextant and ended up with an interecept of only one nautical mile!
Doing the math:
Hs 57°57' IC. - 2 Ref. -1 Dome. -4 Ho. 57°50' Hc. 57°51'
Intercept 1' Away
The refraction corrections came from the Air Almanac including the additional "Dome" correction for observations taken through the standard astrodome.
Hc was computed with Reed's exellent "GPS anti-spoof" app. which I highly recommend.
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Here are some links to the 2010 flight:
https://navlist.net/CN-aboard-Cessna-172-Rudzinski-jan-2010-g11467
https://navlist.net/CN-aboard-Cessna-172-Rudzinski-jan-2010-g11483
https://navlist.net/Cessna-CN-Summary-LaPook-jan-2010-g11496
https://navlist.net/Cessna-CN-Summary-LaPook-jan-2010-g11498
https://navlist.net/CN-aboard-Cessna-172-LaPook-jan-2010-g11510
