[vsnet-chat 2346] standard clusters

[aah@nofs.navy.mil]

M67 has become pretty much a standard cluster for
photometry.  Several excellent papers have been published,
and a few dozen stars therein have believable photometric errors
less than one percent.  Such fields have many advantages
in calibrating CCD equipment, especially if they have good
astrometry in addition to UBVRI photometry.
  I've proposed in the past that NGC7790 be another of
these standard clusters.  Towards that end, I've put on
http://ftp.nofs.navy.mil/pub/outgoing/photom/ngc7790.gif
http://ftp.nofs.navy.mil/pub/outgoing/photom/ngc7790.std
a finding chart and preliminary photometry list of a set
of stars that are bright enough for most amateur telescopes,
are reasonably isolated, and have a fairly wide color range.
Over the next couple of months, I will improve this list
to give the best possible accuracy.
  However, neither M67 nor NGC7790 are easily available
to our southern observers.  Could someone propose a
similar field that could be established as a standard
region?  Reasonable criteria:  between 0 dec and -25dec
(so that I can reach it); lots of stars within a 10arcmin
field that are between 9th and 14th magnitude; a wide
color range; not too crowded; preferably in the 16h RA
range (since NGC7790=0h and M67=8h).  There are a couple
of Landolt standard fields that might fit these criteria,
especially fields like SA110-503, but I'd prefer an open
cluster or similarly identifiable region.
Arne

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