[vsnet-chat 3081] Re: (fwd) Globular Variables (Greaves)

[Brian Skiff <bas@lowell.edu>]

     The general lack of accurate coordinates for the variables in globulars
is (in my opinion) a serious lacuna in the literature.  The system of ad hoc
x,y offsets is an anachronism inadequate for modern observing.  I'd like
to suggest therefore that since John has started the work that he
publish it.  The x,y coord systems do not always have their origin at the
center of the cluster, but instead are sometimes for a specific star in the
field or for a specific RA/Dec (usually to only 1' accuracy!).  This varies
cluster-to-cluster, so has to be determined from Clement's files for each
case.  The lack of coordinates has resulted in papers claiming large numbers
of supposedly new variables in at least one globular found by Space Telescope
folks which in fact were mostly known.  In completing such work, it will
be necessary both to make a large number of cross-IDs and also to generate
new positions for objects with poor or incorrect x,y coordinates---if you
want to do it right.

\Brian

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