cdfp_usno_wcs_stars

This is a specialized OTW code desined to take the USNO file from usno_00.py (usually named something like usno_all.cdfp) and extract only the well-classified stars. This is done to provide very point-like, high S/N sources for use in WCS derivation. The run command line is: 

 

% cdfp_usno_wcs_stars.sh usno_all.cdfp
The output (in CDFP format) is written to standard out, and in a script (like skygrab) I redirect to a file named usno.cdfp. The recipe for a source getting into the usno.cdfp output is:
  1. Any object above stellarity sg>5 and sg<15 is called a STAR
  2. The source must have boteh Blue and Red magnitudes
  3. The source must be classified as a STAR in both colors
This greatly cuts down the number of possible calibration sources compared to the full USN catalog list, but this recipe nearly always produces a large list of calibration stars.



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