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    Re: Lunar eclipses and other things
    From: Herbert Prinz
    Date: 2004 Oct 29, 17:36 -0400

    Alexandre Eremenko wrote:
    
    > On the other hand, as far as I understand, "Ptolemy system"
    > was not Prolemy's invention, the principle belongs to
    > Hypparchus, and Ptolemy could only modify or improve it.
    
    It does not belong to Hipparchus at all. Hipparchus had no _system_, only isolated
    theories about the sun, the moon (a simple one), precession and probably a star
    catalogue. No planetary theory what so ever.
    
    Ptolemy had a model of the solar system. The physical aspects are described in the
    Planetary Hypotheses, the mathematical aspects in the Almagest. The defining
    characteristic of his system is the idea that the centre of uniform motion is not
    necessarily the centre of the orbit. This was the solution to the puzzle that
    Hipparchus could not solve.
    
    Herbert Prinz
    
    
    

       
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