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    Re: equinox
    From: Fred Hebard
    Date: 2004 Mar 21, 15:20 -0500

    My calculation was based on the Nautical Almanac, which had a 0 degree
    declination for the Sun exactly at 6:48:00 UT.  The Sun's GHA is
    adjusted by up to 1.5' to reduce the error arising from ignoring the v
    correction.  The GHA of the Sun may be in error by up to 0.25'.
    
    MICA reports:
                                          Sun
    
                             Apparent Topocentric Positions
                               Local Zenith and True North
    
                      Location:  E 79?51'26",   0?00'00",     0m
                      (Longitude referred to Greenwich meridian)
    
        Date        Time          Zenith          Azimuth        Distance
             (UT1)               Distance        (E of N)       to Object
    
                  h  m   s        ?  '   "        ?  '   "          AU
    2004 Mar 20 06:48:00.2       0 00 02.4     111 21 02.9     0.995960666
    2004 Mar 20 06:48:00.3       0 00 01.1     141 03 00.3     0.995960666
    2004 Mar 20 06:48:00.4       0 00 01.2     223 27 24.7     0.995960666
    2004 Mar 20 06:48:00.5       0 00 02.5     249 45 07.1     0.995960667
    
    
    The Naval Observatory reports 6:49 for the vernal equinox:
    2004                        2004
    Perihelion  Jan   4 18    Equinoxes  Mar   20 06 49    Sept  22 16 30
    Aphelion    July  5 11    Solstices  June  21 00 57    Dec   21 12 42
    
    Perhaps one of the astronomically literate will explain the discrepancy.
    
    On Mar 21, 2004, at 2:01 PM, Gary Harkins wrote:
    
    > In a message dated 3/21/2004 1:23:55 PM Eastern Standard Time,
    > legras{at}MAD.SCIENTIST.COM writes:
    > spring equinox was on earth 20/03/2004 at 06:49 utc according to Jean
    > Meeus' sky calender 2004
    >
    > On which planet does it occur at 6:48 ????
    >
    > Using the Nautical Almanac and interpolating between .8' South at 0600
    > utc and .2' North at 0700 utc the equinox calculates to occur at
    > exactly 0648 utc.  Are you saying that Jean Meeus' sky calendar is
    > more accurate than the nautical almanac?  Does he carry his
    > calculations out to more precision than .1' of declination?  And who
    > cares anyway, it's cold as most winter days here regardless of what
    > the calendar says.
    
    
    

       
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