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    Re: Lunars for dummies like me
    From: Jan Kalivoda
    Date: 2004 Sep 24, 15:51 +0200

    Jim Thompson wrote:
    
    >Was it is as obvious as it seems to be -- simply adding the
    >number of hours and minutes of LAT to 1200,
    >and then adjusting the hands of
    >the clock to match that time?
    
    
    If I understand you well, Jim, I agree with you. The time sight of the Sun
    gave sailors a reliable westing or easting LHA of the "apparent"  = true
    Sun, the dial pointer of  LAT. If you express it in hours, minutes and
    seconds, then the task of obtaining LAT is simple arithmetics, adding
    westing LHA or subtracting easting LHA to/from 12 and setting the clock
    accordingly. Of course, old seamen used to gain LHA in time units directly,
    as their logarithmic result (by most formulas using measured altitude of the
    Sun, DR latitude and declination of the Sun) was log hav LHA, tabulated as
    "log rising" against arguments in time units. In addition, in many tables
    they could immediately read the time from the precedent midnight (= LAT
    during AM hours) for easting LHA's of the Sun.
    
    The date of their observation was another issue. The civil, astronomical
    (almanac) or nautical date - they had to choose. George Huxtable wrote the
    article on this problem for the list some time ago.
    
    
    Jan Kalivoda
    
    
    

       
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