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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: UT1 vs. mean time in old almanacs
From: UNK
Date: 2010 May 26, 16:54 +0000
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
