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    Re: Timing noon.
    From: George Huxtable
    Date: 2002 Apr 12, 06:09 +0100

    In response to the following question about estimating the time of local noon-
    
    >"As I see it, no other input is required than altitudes of the Sun
    >measured
    >at suitably chosen times, a knowledge of the North-South component of the
    >ship's speed, and the rate of change of declination. Does Walter agree?"
    
    Walter Guinon said-
    
    >I think the E/W component of the ship's speed must also be incorporated in the
    >solution.
    
    Well, I doubt that, and invite Walter to reconsider his opinion. As I see
    it, Easterly motion, against the Sun, increases both the rate of rise of
    Sun's altitude before noon, and the rate-of-fall after noon, without
    affecting the symmetrical moment of noon itself. The maximum altitude will
    occur at the same moment for a vessel heading East as for a stationary
    vessel. Similarly, Westerly motion reduces those rates of change. So such
    motion has no effect on the result, though it may change the shape of the
    curve that Walter's proposed method is trying to fit. Can he persuade me
    otherwise?
    
    George Huxtable.
    
    
    ------------------------------
    
    george---.u-net.com
    George Huxtable, 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
    Tel. 01865 820222 or (int.) +44 1865 820222.
    ------------------------------
    
    
    

       
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