
Config (.ptolemyrc) variables used by relastro:

  RELASTRO_SIGMA_LIM   : exclude measurements with dMag > SIGMA_LIM for image calibrations
  PM_DT_MIN            : minimum temporal baseline needed to calculate a proper motion
  PM_TOOFEW            : minimum number of valid detections to calculate a proper motion
  POS_TOOFEW           : minimum number of valid detections to calculate an average position

  CATDIR               : database directory

  GSCFILE              : template sky layout definition table (used for CATDIRs created before this feature)
  SKY_DEPTH            : define the output sky catalog size
  SKY_TABLE            : specify an alternate name for the sky catalog table

  PHOTCODE_FILE        : template photcode table (used for CATDIRs created before the photcode table was added to catdir)

  CATMODE              : define the output catalog mode (mef,split,etc) -- this is ignored
  CATFORMAT            : define the output catalog format (eg, PS1_DEV_1) -- this is ignored
