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    Re: N.A. + Moon phase
    From: Bill B
    Date: 2004 Oct 31, 16:42 -0500

    >> So,I'm not grasping what you mean by "observer position" as reguards to
    >> the moon phases/time referance.If the Moon's visible one would see it in
    >> the phase stated no matter where one's position on earth is?
    
    Doug
    
    If I understand it correctly, because of its relative nearness to Earth, the
    Moon has a lot of parallax.  So an observer viewing it between the center of
    Earth and the moon would have a different angle and therefore "view" than
    someone viewing it 90d from the first observer.
    
    Using radius of the earth as 4,000 miles, and an average distance to the
    moon of 236,000 miles, that angle is a bit under 1d.  A 2d difference for
    observers on opposite sides of the Earth (with a line segment connecting
    them going through the center of the Earth.
    
    Therefore, while the viewer between the Earth' center and the Moon saw it as
    50/50, one of the other viewers would see it approaching 50/50, while his
    opposite would see it as having past 50/50 already.
    
    While still inside my sphere of ignorance, I suspect this is the effect Alex
    was looking at when he timed the phases of the eclipse at his location as
    opposed to the time published in the almanac.
    
    Thanks again,
    
    Bill
    
    
    

       
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