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    Re: UT1 vs. mean time in old almanacs
    From: UNK
    Date: 2010 May 26, 16:54 +0000

    Antoine Couette wrote:
    >
    > The 40" in Longitude Error mentioned by Lalande would imply that
    > Lacaille did not include ANY perturbation whatsoever because a 40"
    > Longitude perturbation for the Earth is very close to the maximum
    > total value of all perturbations from all other planets.
    >
    Au contraire, it implies that Lacaille included nearly ALL planets that
    matter, namely: Moon, Venus and Jupiter! Actually, the fourth minor
    equation, ca 10" for nutation, does not come into play for EoT. But
    then, the inclusion of perturbations on dynamic principles was not
    Lacaille's only improvement. He also reduced Cassini's Equation.of
    Center from 1;55,50 deg to 1;55,30 deg - which does affect EoT
    systematically.
    
    Herbert
    
    
    
    

       
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