NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Francis Upchurch
Date: 2015 Jul 18, 21:25 -0700
Lu,
I've done hundreds of cel nav sights on my 35ft yacht over the last 10 years or so and agree with Greg. 1-2' sextant accuracy in the back yard ok but on the boat in a seaway, that is another matter! (3-5' often, but sometimes 10'). Lunars very difficult in rough weather. (Greg, I'm interested to hear you can do lunars with a 7x scope. I find even my 4x scope difficult in any swell. )
So I still think the sextant reading is often the main source of error at sea. (see my previous posts on that).
Obviously, you want to limit any addtional sources of error, like the LOP sight reduction calculation which has been the main discussion point here.If it is in the opposite direction to the sextant error, great, but that would be pure luck, may be same direction and compound the sextant error.
Practice nearly makes perfect. My sextant performance seems to improve by the end of the cruise.Likewise my LOP reductions (I generally use the Bygrave)
Best wishes
Francis
