[vsnet-id 428] re VX & FU Dra

[crawl@zoom.co.uk]

I wrote:

>Interestingly FU Dra appears to have a very large proper motion, with about
>15 arcsec of difference between the 1984 GSC plate position and the 1991.25
>epoch Hipparcos position, so this could well be interesting in light of a
>1921 VX Dra position... ...however the declinations seem problematic,
>unless the VX Dra declination carries a typographic error somewhere along
>the line [a not unknown occurence].

I checked the AC2000 position of FU Dra and found that the GSC position
must be not very good.  After all, the Hipparcos position lies _between_
the AC2000 and GSC position, which would mean the thing would have had to
do a 180 degree about face in mu at some point!

Anyway, thanks to Emile Schweizer for the AN details!

Despite FU Dra being part of the AC2000 there is no AC2000 object anyway
else nearby, especially not for the putative VX Dra position, which I feel
aids Jochen Pietz' viewpoint.

Simply, it is most likely that the originally listed position was a bit
spurious.  I believe Pulkova Observatory regularly took "patrol plates"
during prewar times, and I'm pretty certain that they were not part of an
astrometric survey, while positional reduction on relatively large plates
can be a tad problematic at such high declinations.

Were the Pulkova patrols searching for variables?  A declination that far
north would not normally be used for asteroid and/or comet patrols, or even
novae for that matter.

Cheers

John

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