[vsnet-chat 4930] Re: new southern variables

[Brian Skiff <bas@lowell.edu>]

     This looks like very useful stuff, and I encourage Vello to proceed
with the work.  For inclusion in databases it will be necessary to have
at least an approximate zero-point for the magnitudes.  Given the 
magnitude limit, I would use "good" Tycho-2 stars (errors < 0.03 in both
VT and BT), and given the instrumentation, I would transform to Cousins R
using equations Arne Henden has provided.  It would be better to have a
separate transformation for the obvious Miras and LPVs (i.e. the red stars
with a lot of far-red/near-IR output), perhaps simply a zero-point fudge-
factor.
     Convert everything using at least two (preferably more, up to 5 or 7)
comparison stars to standard R.  Make a list of coordinates to identify
the stars.  These should be found from a current "catalogue of precision",
in the south meaning specifically UCAC1.  It may be helpful to examine each
star on digitized sky survey images to check for crowding etc and verify
the identification.
     For the cyclic variables:  once you have about three cycles in hand,
and the period is reasonably determinate, I would bundle up the stars in
batches of 50 or 100 and publish them with finder charts and lightcurves
in the IBVS.  The data going into the lightcurves can be included as links
to the on-line version of the paper(s).  An example of the final product
(sans lightcurves) can be seen in Lennart Dahlmark's recent list:

http://vsnet.konkoly.hu/cgi-bin/IBVS?5181

Dahlmark has his data logged by hand, so there are no lightcurves, although
I am hoping to get his data keyed-in eventually.  With your automated
set-up, you can generate the lightcurves readily, so this is not a problem.
     I'll be pleased to help with the catalogue identification part if
desired, mainly because I don't want to see additional clutter in the
stellar databases.  Bulk search in VizieR, as Fraser suggests, do work most
of the time, but there are some subtleties that can trip you up here and
there.

\Brian

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