NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Equal altitudes and double altitudes.
From: Geoffrey Kolbe
Date: 2010 Jun 10, 20:06 +0100
From: Geoffrey Kolbe
Date: 2010 Jun 10, 20:06 +0100
> >Jim Wilson asked - > >"I understand that the purpose of the double altitude sight is to get time >of meridian passage. Is there another use?" > >and Geoffrey Kolbe replied- > >".... In fact, before the advent of GPS technology, it was probably the most >accurate way of deriving longitude available - giving very similar >precision. George Huxtable said >When Geoffrey says "giving very similar precision", then I ask- similar to >what? I am guilty of an incorrect use of the term, "precision". I should have said, "accuracy" What I meant was the same accuracy as the commonly available GPS receiver, where the circle of uncertainty in position has a radius about 5 metres. Geoffrey Kolbe
