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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: The term AP
From: John Karl
Date: 2015 Jan 19, 19:49 -0800
From: John Karl
Date: 2015 Jan 19, 19:49 -0800
Doug & all,
I don't like the term "trial position" for the same reason I don't like "assumed position." In the St. Hilaire sight reduction we are not trying, experimenting, or assuming anything. Knowing the body's GP and Ho we can compute the entire exact circular LOP. St. Hilaire gives us the azumuth, and great circle distance, to the nearest point (a PLOP) from the AP to the LOP. Knowing this azimuth, we can appoximate the LOP (at the PLOP) with a straight line perpendicular to the intercept. It's the most efficient method of extracting, from only two equations, a very useful approximation to the LOP.
J. Karl
