Yet Another Use for TASS measurements

[Stupendous Man <richmond@a188-l009.rit.edu>]

  Brian Skiff sent me the following message, which describes his
use of the Mark III "tenxcat" catalog.

                                            Michael

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     Recently I have been 'exploring' the old Dearborn red stars catalogue.
This survey was completed about the time of WWII and includes 44,000 "red"
stars north of about -5 Dec and brighter than V ~11.  The ReadMe file for
the machine-readable version can be found here:

http://vizier.u-strasbg.fr/viz-bin/Cat?II/68

The original positions are quite rough, with typical errors of 2'-3', and 5'
offsets are not uncommon, so the first task has been simply to recover the
stars on the sky.  After that, I have made identifications with the traditional
HD and BD catalogues, plus GSC, IRAS, and other modern catalogues as relevant.
Cleaned up results for the first 1100 Dearborn stars are copied out to the
Lowell ftp area:

ftp://ftp.lowell.edu/pub/bas/starcats/dearborn.sample

     Nearly all the stars appear in Tycho-2, and I use the Tycho colors
to identify the stars.  However, it is clear that for fainter stars the 
Tycho colors can be erroneous, specifically too blue, since non-detections
in the blue (BT) band end up skewing the reported blue magnitude to a brighter
value, making the star seem less red than it really is.  For stars south of 
about +2 Dec, this is where the TASS MkIII 'tenxcat' data come to the rescue.
The TASS data reach rather fainter than the Dearborn catalogue, so the V-I
colors especially are unambiguous about the relative redness of stars near the
nominal Dearborn positions, making it easy to identify the intended stars.
Since I'm looking for gross differences in color, the fact that the MkIII
data have errors of ~0.1 mag. is not important when comparing V-I of, say, 0.6
against V-I of 2.0 or larger.  Although the notes at the bottom of the sample
list have a few remarks giving specific use of the MkIII data, it was used as
a diagnostic far more often.
     As per the coverage map in TechNote 56, I'll be running past the main
block of MkIII data soon in the southern zone of the Dearborn list.  I'm gonna
miss having it!  Thus you might consider this a plea for more results from the
new systems.  Tom D keeps urging folks to start on MkIV reductions, but this is
a request from someone outside the group who actually wants to use the data.
My interest is simply to have reliable V and V-I (or some color) for stars of
intermediate brightness generally.  Incidentally, I access 'tenxcat' with the
Strasbourg VizieR utility, since it allows me to search on bulk input lists in
both Tycho-2 and the MkIII data at the same time.  It's a nice tool, and I'm
glad you published the file so that the Strasbourg folks could include it in
their system.
     About half the Dearborn stars, by the way, are solid M-type stars, and
are certainly variable, though perhaps only at the few percent level (I show
GCVS names in the file only when SIMBAD has missed them).  These are stars to
check for variability if not already known.  Nearly all the designated red
variables are essentially unstudied as to lightcurve anyway, so it hardly
matters whether one of these stars is a known variable or not---they all need
work.

\Brian