A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Geoffrey Kolbe
Date: 2019 Sep 30, 22:25 -0700
Tracy, you said:
"My sun sight was straight out my left window and the resulting LOP grazes my FMS location by maybe 6nm. I took the moon sight diagonally accross the cockpit through the left windshield, at an angle easily less than 50° through the glass. The resulting LOP is 30 some miles at it 's closest to my FMS."
This seems to echo my experience, that at times I was feeling pleased that I was getting very acceptable results and then at other times I was well off the mark. Refraction through the cabin windows undoubtedly contributes some error - but the best part of a degree? I think I would need a lot more experience before I could sift out what the real problems were and mitigation strategies for them. But the sextant has an averager for a reason and next time I get the chance I will certainly use it.
Thanks for your comments