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    Re: sight reduction tables
    From: Marc Bernstein
    Date: 2007 Sep 28, 18:54 -0400

    On 9/28/07, George Huxtable  wrote:
    > Of course, HO 249 achieves its condensation by sacrificing precision,
    > working only to 1 minute instead of 0.1 minutes. And that allows the chosen
    > stars to have fixed positions, whereas aberration alone can shift some stars
    > by up to 0.3' each way, over a year. But it leaves another question in my
    > mind. How does HO allow, for its named stars, for the slow drift in star
    > position caused by precession? Is there some way provided of correcting for
    > this drift, year on year? Or is Vol 1 of HO249 reissued after a period, when
    > precession starts to put star positions unacceptably far out?
    Exactly! An updated edition of Vol 1 is published every 5 years. The
    Epoch 2010.0 edition, as they call it, should be out shortly.
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