A note on the First Point of Aries

From: Matson, Robert (ROBERT.D.MATSON@saic.com)
Date: Wed Apr 03 2002 - 18:28:50 EST

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    Hi Jeff and List,
    Jeff wrote:
    > The point of reference for a sidereal day is an imaginary point
    > way out in deep space which is considered to be fixed because
    > it is so far away.  It is also called the First Point of Aires <sic>
    > - along a line from the center of the earth through the equatorial
    > plane at the point when the Sun passes from the southern
    > hemisphere to the northern hemisphere on the first day of
    > spring (vernal equinox).
    It is interesting to note that the "First Point of Aries" is
    actually a bit misleading today.  When the equinox was first
    observed, many thousands of years ago, this point actually did
    lie in the constellation of Aries.  However, due to precession
    of the earth's pole, the First Point of Aries crossed into the
    adjacent constellation of Pisces in about 70 BC.  So it should
    actually be called the "First Point of Pisces" since we now live
    in the "Age of Fishes".  (Not being a religious scholar, I'm
    guessing this is the reason for those Christian fishes on the
    backs of autos?)
    The Point's journey is now about 75% complete through Pisces;
    in another 600 years, it will pass into Aquarius (so now you
    know what was meant by the musical Godspell's "Age of Aquarius").
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