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    Re: Sextant Positions versus Map Datums?
    From: Bill Murdoch
    Date: 2002 Jan 18, 11:29 AM

    Aren't we missing the original question ?
    
    > How does the WGS84 ellipsoid compare with the astronomers one?
    
    From the coordinates systems section of the website mentioned earlier:
    http://www.colorado.edu/geography/gcraft/notes/coordsys/gif/difsys.gif the 
    position of the star in the hand of the Goddess of Liberty atop the capital 
    dome in Austin, Texas is:
    
    NAD 83 --  30:16:28.82N, 97:44:25.19W
    NAD-27 --  30:16:28.03N, 97:44:24.09W
    WGS-72 --  30:16:28.68N, 97:44:25.75W
    
    If I were to climb to Libery's shoulder, sit on the star, and determine my 
    position with a sextant, a bowl of water, the Nautical Almanac, sight 
    reduction tables, and the heavens (and do it perfectly), what would the 
    position of the star be ?
    
    If I were to do the same from every point on the surface of the earth, where 
    would I find the greatest deviation from the position determined by a GPS set 
    to (say) WGS84 ?
    
    Bill Murdoch
    

       
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