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    Winter solstice sunset and sunrise
    From: Jim Thompson
    Date: 2003 Dec 23, 07:34 -0400

    Pierre,
    
    I found this in Bowditch section 1521: "The error due to lack of uniform
    rate of revolution is removed by using a fictitious mean Sun. Thus, mean
    solar time is nearly equal to the average apparent solar time. Because the
    accumulated difference between these times, called the equation of time, is
    continually changing, the period of daylight is shifting slightly, in
    addition to its increase or decrease in length due to changing declination.
    Apparent and mean Suns seldom cross the celestial meridian at the same time.
    The earliest sunset (in latitudes of the United States) occurs about two
    weeks before the winter solstice, and the latest sunrise occurs about two
    weeks after winter solstice. A similar but smaller apparent discrepancy
    occurs at the summer solstice."
    
    Jim Thompson
    jim2{at}jimthompson.net
    www.jimthompson.net
    Outgoing mail scanned by Norton Antivirus
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