Data Set Overview
  =================
 
  This data set is intended to include published broadband colors of centaurs
  and Transneptunian Objects (TNOs) published through March 2013.  It also
  includes some comets with Centaur orbits.
 
  Data
  ====
 
  Data were collected from the published literature and include
  Johnson-Kron-Cousins color indices and one-sigma uncertainty values.  Many
  objects have data reported by several groups.  Details of the observations
  and data reduction are to be found in the individual papers.  Note that only
  UBVRIJHK colors are included in this collection.  For ECAS colors of Centaur
  2060 Chiron, see the PDS ECAS data set, EAR-A-2CP-3-RDR-ECAS-V4.0.
 
  Results on objects with comet designations are provided in a separate file,
  cometcencol.tab.
 
  Archiving History
  =================
 
  The TNO colors data set, EAR-A-3-RDR-TNO-PHOT, was first introduced in 2000
  and has been updated mostly annually since then.  At the 2004 review, a data
  set compiling colors of Centaurs was also introduced, and it was decided to
  combine the two to make a new data set.  A column was added to the data
  table to indicate whether the object is a TNO or a Centaur.  In the 2009
  update, a column was added to specify if the measurement was made of the
  primary or secondary, or of the coma or nucleus, of the target body.  In
  2010, the column identifying the dynamic classification (TNO or CEN) was
  changed to reflect the classification by the MPC (TNO or CEN/SDO) rather
  than the assignment made by the individual publication, as it had been in
  earlier versions of the data set.
 
  This data set supersedes all the versions of the TNO colors data set,
  EAR-A-3-RDR-TNO-PHOT.

Confidence Level Overview
  =========================
    We assume the R-bandpass used by the various observers is in the
    Kron-Cousins system, but that this cannot be verified for all of the
    measurements included in this data set.
 
    Some entries provide colors which result from the combination of multiple
    observing runs, sometimes over several years.  These results have no
    single observing date.  For asteroids, these results are provided in a
    separate file, multirun.tab, to discourage their inappropriate use.  For
    cometary objects, these results are provided in the comet file,
    cometcencol.tab, with a null value of 9999-99-99 for the observing date.
    (The comet file is so short this is unlikely to result in confusion.)  See
    the original papers for information about the observing dates for these
    results.
 
    Refer to the individual published papers for the confidence level of any
    individual measurement.