re photometry sources

[jg <jg@jgws.freeisp.co.uk>]

I don't think the following'll be any use for calibration, but it could
be useful for assessment (???)  Certainly it should provide a largeish
number of objects to test against.

Tom's current region of imaging takes in NGC 6633, NGC 6709, IC 4756 and
IC 4665, a group of well populated and in some cases relatively sparse
(the IC objects) open clusters that have quite a bit of photometry (V
and B-V at least, not sure about Ic) available for them.  This includes
stuff up to 6th mag, and there's the odd K giant or two with respect to
colour range, but mostly these'll be white to blue stars.

The Lausanne database and Mermilliod et al's open cluster catalogues
have data for these, other sources may exist elsewhere.

I'd expect the IC 4665 stars at least to crop up as individual objects
in the TASS dataset soon to be made available online, it being a
binocular resolvable cluster.

Cheers

John G.