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    Re: Time of meridian passage accuracy
    From: George Huxtable
    Date: 2009 Sep 26, 00:44 +0100

    Douglas Denny has missed the point. The nearness of his observation point to
    Greenwich has nothing to do with it. The time correction, due to changing
    declination, as the same the whole world over, at the same latitude and
    time-of-year..
    
    His calculated time of Meridian Passage may well be correct. But he isn't
    observing Meridian Passage, when the Sun is due South. He is observing
    maximum altitude, the peak of the curve, which is subtly different.
    
    George.
    
    contact George Huxtable, at  george{at}hux.me.uk
    or at +44 1865 820222 (from UK, 01865 820222)
    or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
    ----- Original Message -----
    From: 
    To: 
    Sent: Friday, September 25, 2009 11:48 PM
    Subject: [NavList 9933] Re: Time of meridian passage accuracy
    
    
    
    I wrote:-
    
    "You will also note from the graph of my example, that the maximum altitude
    was
    within one minute of arc for approx plus and minus ten minutes of time. This
    is the main point in question here I believe - that obtaining Mer passage at
    the location to within one minute of time using an Equation of Time within
    this limit is  _more_  than adequate".
    
    ---------
    
    I should have also mentioned you will note from the graph that Mer passage
    at Bosham is exactly as calculated coinciding with the peak of the curve,
    because I calculated the declination at the exact time for Greenwich Mer
    passage for the day and time, and also calculated Equation of Time for that
    time exactly too.
    
    I could have further calculated for the exact time for the Mer Passage at
    Bosham - but as mentioned - negligable difference so did not bother.  I
    might have done so if I lived, like Bill,  in New Zealand.
    
    
    Douglas Denny.
    Chichester. England.
    
    
    
    
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