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    Re: Sine curve to approximate declination
    From: George Huxtable
    Date: 2004 May 20, 22:03 +0100

    I detect a certain amount of wriggling here by Frank Reed, in his response
    to Trevor Kenchington's objections, and mine, to the "broader shoulders" he
    gives to the variation of declination.
    
    We all were (weren't we?) discussing how the declination would vary with
    date-of-year, which (assuming a circular orbit for the Earth, as we were)
    would change exactly proportionally with ecliptic longitude. So why would
    we be even considering how it changes with the right-ascension of the true
    Sun, which would NOT change linearly with time?
    
    So when he explains it away by saying-
    
    "So the difference between these two points of view amounts to a difference
    in choice of independent variable."
    
    there isn't really any such choice. Only one of those variables is relevant
    to the problem in hand.
    
    I'm glad he has cleared the matter up by concluding-
    
    "If you graph the Sun's declination versus time, then you get straighter
    sides (narrower shoulders)."
    
    George.
    
    
    ================================================================
    contact George Huxtable by email at george---.u-net.com, by phone at
    01865 820222 (from outside UK, +44 1865 820222), or by mail at 1 Sandy
    Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
    ================================================================
    
    
    

       
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