[Aavso-photometry] SU TAU

[Tim Hager]

Brian,
    I just checked the online version of the GCVS and the coordinates agree
with the AAVSO chart.  The GCVS folks have been engaged in a long term
project to assign more accurate coordinates to the variables in the GCVS.
The most recent coordinates for the stars that they have revised are always
on their online site which is at:

http://www.sai.msu.su/groups/cluster/gcvs/gcvs/

Try the GCVS query form.  If you are using an older printed copy of the
GCVS, the coordinates might not be up to date.

I also checked the Aladin image display system (
http://aladin.u-strasbg.fr/aladin.gml ) and the correct star is indicated as
the variable on the AAVSO chart.  By the way, the F scale chart might be a
little easier to use if you are doing photometry with a ccd.

...Tim (HTY)

-----Original Message-----
From: aavso-photometry-bounces at mira.aavso.org
[mailto:aavso-photometry-bounces at mira.aavso.org]On Behalf Of Brian C.
Barnes
Sent: Monday, December 27, 2004 12:44 PM
To: aavso-photometry at mira.aavso.org
Subject: [Aavso-photometry] SU TAU


I've recently added SU TAU to my list of variables I'm monitoring. The AAVSO
chart (SE0401) lists SU TAU as 05 49 03.7, +19 04 22 (J2000.0), with a
rather bright (but unlabeled) star to the NW. At the given location I've
found a rather bright star, of approx. 10.11 MagV. I've noticed that lots of
folks have submitted observations for this star. My problem is that,
according to my copy of the GCVS, SU TAU is actually at 05:49:23.37, +19 04
04.78, south and east of this brighter star. According to photometry of my
image, at the GCVS location is a star, but it is too dim in my image (20
seconds) to get any MagV data on - my dimmest star is MagV 15.83 +- ~.5.

So my question is, is the AAVSO chart correct and the GCVS catalog is wrong,
or is the GCVS correct, and lots of folks have been submitting observations
for the wrong star? I'd like to be certain of my data.

Brian C. Barnes

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