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    Re: UT1 vs. mean time in old almanacs
    From: Antoine Couëtte
    Date: 2010 May 27, 00:51 -0700

    Dear Herbert,


    OK ! Now, I see what you meant when initially writing in :

    [NavList 13106] Re: UT1 vs. mean time in old almanacs

    From: 666---org Date: 26 May 2010 06:02

    QUOTE

    On the occasion of introducing Lacaille's solar tables into the CT in 1760, Lalande remarked that the neglect of perturbations could hitherto have introduced errors up to 40" in the longitude of the sun. Was he wrong?

    UNQUOTE

    I initially mis-understood your question just hereabove, and from your very last post in :

    [NavList 13108] Re: UT1 vs. mean time in old almanacs From: 666---org
    Date: 26 May 2010 16:54

    I now can see that we are in full agreement on Lalande's remark.

    Indeed Lalande was right : neglecting [ all planetary ] perturbations could introduce errors up to 40" in the Sun's position as seen from the Earth. This value of 40" can be easily checked nowadays through taking a look at the perturbations given in the VSOP87 [R,L,B]series and even also from the most celebrated Tables of the SUN by M. Simon E. Newcomb in "A.P. for the A.E.N.A." VOL VI, 1898, pp. 13, 14, 15 and 16 which are given as [log10(R),L,B]


    Best Regards


    Antoine M. "Kermit" Couëtte
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