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    Re: Meridian Transit of the Sun and Daily Pages
    From: Paul Hirose
    Date: 2015 Oct 12, 16:42 -0700

    On 2015-10-11 13:37, Stan K wrote:
    > For example, for 0h UT on 1 January 2015, the values of GHA of the Sun are given for several sources:
    > USNO web site			179º12.2'
    > Nautical Almanac		179º12.0'
    > Reed Navigation			179º12.1'
    > sun.xls				179º12.1'
    > Navigator Lite			179º12.2'
    > Nautical Almanac (Ruiz)	179º12.2'
    > Celestial Tools (Accurate)	179º12.2'
    > Celestial Tools (NA)		179º12.0'
    >
    >
    > Other sources have values of 179º12.22', 179º12.17', 179º12.169' (which all 
    round to 179º12.2'), 179º12.2', and 179º12.1'.  Rounded to 0.1', 11 of the 14 
    sources I checked say 179º12.2'.
    
    
    According to the results below, a trifling decrease of about 1.1″ in GHA
    would make a program round down rather than up to the nearest .1′. That
    may explain some of the discrepancies noted by Stan.
    
    My sexagesimal angles were converted from decimal values at full
    accuracy, not the rounded values in the left column. That's why the
    first two lines have identical decimals but different sexagesimals.
    
    179.20280°  (179°12′10.08″)  USNO MICA 2.2.2
    179.20280°  (179°12′10.09″)  JPL HORIZONS [1]
    179.20281°  (179°12′10.12″)  SofaJpl 2.0 demo program [1]
    179.20281°  (179°12′10.12″)  Tinyac [1]
    
    [1] Program is capable of greater precision but I did not request it.
    
    

       
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