NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Dip uncertainty
From: Alexandre Eremenko
Date: 2004 Dec 6, 10:40 -0500
From: Alexandre Eremenko
Date: 2004 Dec 6, 10:40 -0500
Dear Bruce and George, I tend to accept George's explanation (and most importantly the conclusion that dip uncertainty should INCREASE with the observer's height). The longer path the light ray has to go in the atmosphere between your eye and the horizon leads to larger dip uncertainty. The real problem with small boats should be that you usually do not see the horizon because of the waves. Alex. On Mon, 6 Dec 2004, George Huxtable wrote: > And what dip affects observations from that vessel? The standard dip, from > the almanac, is doubled. The anomalous part of the dip will be, initially, > the same as affected me at 2.8 miles, but now the light goes on, still > close (from 6 to 24 ft) to the sea surface, so there's extra curvature > added as a result of that additional 2.8 miles of its path.
