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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Your paper in JoN.
From: George Huxtable
Date: 2008 Apr 7, 17:25 +0100
From: George Huxtable
Date: 2008 Apr 7, 17:25 +0100
Dear Andres, Pleased to see your paper in Jounal of Navigation. Coming from an earlier generation, I didn't really take in vector mathematics as applied to such problems. So much of your paper went over my head. What I want to ask about are your words in 2.3 about correcting for the motion of an observer. An observer who has measured the altitude of a star to be, say 30 deg, knows that his locus is on a circle radius 60 deg centred at the GP of the star, (say, at dec = 0, GHA = 0, as in the example in paragraph 4 of my paper in JoN, 59, No3, pages 521-524, which I think you have). And then the observer moves a known distance, say 60 miles North. His new locus is a closed figure, somewhat egg-shaped, but NOT a circle any longer. Does your algorithm in A2 find the crossings of that non-circle with another circle centred on another star (say, at dec = 1deg N, GHA = 45 deg W, seen at 45 deg alt, as in that example).? What result does it give? Yours, George. contact George Huxtable at george@huxtable.u-net.com or at +44 1865 820222 (from UK, 01865 820222) or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK. --~--~---------~--~----~------------~-------~--~----~ Navigation List archive: www.fer3.com/arc To post, email NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---