A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Greg Rudzinski
Date: 2014 Nov 15, 18:18 -0800
I find that rising bodies tend to be observed too small and setting bodies too large. There are lots of possibles. Incorrect index error, body not centered in optic field, shade error, optic alignment, index/horizon mirror alignment, arc error, land effects (rising hot air or sinking cool air), incorrect assumed position, sextant temperature, eye fatigue, optic focus, cleanliness of optics filters mirrors, relative brighness, and incorrect time. What is not at fault is perpendicularity of the sextant.
From: Randall Morrow
Date: 2014 Nov 15, 13:05 -0800
After thousands of sights from my front walk, they are almost always a bit south and west of GPS. To what do I attribute this? I would expect errors to be more random. Any ideas? It seems to hold true even with sights off by less than 0.5 min. I don't think the fix has ever been to the east or north. Any thoughts?
Kind regards, Randy