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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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