KELT paper -- an "Extremely Little Telescope"

[Tass Mailing List <tass@mail.alembic.net>]

Date: Fri, 12 Oct 2007 11:41:16 -0400
From: Michael Richmond <richmond@stupendous.cis.rit.edu>
To: tass@tass-survey.org
Cc: mwrsps@rit.edu
Subject: KELT paper -- an "Extremely Little Telescope"


  The August 2007 issue of the Publications of the Astronomical
Society of the Pacific has an article on "KELT", which is
a small, automated telescope based on telephoto camera lenses
and CCDs.

  See

       http://www.journals.uchicago.edu/PASP/journal/contents/v119n858.html

or
       http://lanl.arxiv.org/abs/0704.0460


   It has a much larger field of view than the TASS Mark IV, but, most
important, it has a different job: its main purpose is to study a few
fields repeatedly to look for planetary transits.  The system is based
on a CCD with a red-pass filter, which yields an overall response
not _too_ different from R-band.  The authors write at one point of
their photometric calibration:

   "... We find that the R_k magnitudes are within a few tenths
    of standard R-band photometry, with the uncertainty dominated
    by the color term.  Since we do not have V-I colors for all
    our stars ...."

   Hmm.  Sounds to me like the authors might want to look at the
Mark IV measurements, which _do_ provide (V-I) colors for many
of their stars.  One of their telephoto lenses yields results
down to mag 12.5 or so, for which the Mark IV photometry should
be nearly complete (especially for KELT's large pixel size).
Their other lens goes down to mag 16, so it would still suffer
missing (V-I) colors.

   Still, this shows that the TASS results can be very useful.
Many groups are getting interested in large-scale surveys, yet are
too busy to include the multiple filters needed to solve for
color terms in their photometry.  We can help them to do their
jobs better.

                          Michael