NAME:
  siftstar
 PURPOSE:   (one line only)
  Generate filtered lists of stars from a single image tagged by crowding
 DESCRIPTION:
 CATEGORY:
  Photometry
 CALLING SEQUENCE:
  siftstar,fn
 INPUTS:
  fn - filename of the image (string). Do not include path to the file
          in this input. (example: '100704.032')
 OPTIONAL INPUT PARAMETERS:
 KEYWORD INPUT PARAMETERS:
  REDDIR - Path to the data products associate with this image.
            (default='/net/frakir/raid/buie/Reduced/')  Do not include the
            date name in the directory, that part is automatically generated
            from the input file name.
  KEYLIST  - Name of a file containing a correspondence list. This list
                associates a set of standard names with the actual keyword
                names found in a FITS file header. If this keyword is
                omitted, a default list is used, as if a file with the
                following contents had been supplied:
                   AIRMASS   K  AIRMASS
                   DATE      K  DATE-OBS
                   DATETMPL  T  DD-MM-YYYY
                   EXPDELTA  V  0.0
                   EXPTIME   K  EXPTIME
                   FILTER    K  FILTERS
                   FILENAME  K  CCDFNAME
                *  OBJECT    K  OBJECT
                   UT        K  UT 
                *  RA        K  RA
                *  DEC       K  DEC
                *  EPOCH     K  EPOCH
                The middle column is a flag. It may be K, for Keyword,
                T, for Template, or V, for Value. If it is V, the contents
                of the third field on that line should make sense for the
                name in the first field.  Only those fields marked with '*'
                are actually used by this program.
  VERBOSE - Flag, if set turns on lots of printed and graphical output

 OUTPUTS:
  Writes two file files to REDDIR+'Src/'
    fn+'.sr1' - data for large photometric aperture sources
    fn+'.sr2' - data for small photometric aperture sources
 KEYWORD OUTPUT PARAMETERS:
 COMMON BLOCKS:
 SIDE EFFECTS:
 RESTRICTIONS:
 PROCEDURE:
  Get source list from rdir+root+'/Src/'+root+fn+'.srd
     need x,y,ra,dec
  Get photometric aperture size from rdir+root+'/reduc.inf'
     use rdreduc, this will get objrad,sky1,sky2,gain,rdnoise,ddir
  Grab the image and its header from ddir+root+'/cal/'+fn
     need the image array and exposure time (info.exptime)
  Call photiso with big aperture, saving the sky --> list1
  Call photiso with small aperture, reusing the sky --> list2
  Remove list1 from list2 (intrsect)
  Save results (for each list)
      x,y,fwhm,mag,err,ra,dec,snr   (mag goes with aperture for the list)
      make sure to augment the header to save things like apertures
 MODIFICATION HISTORY:
  2011/01/13, Written by Erin R. George, Southwest Research Institute
  2011/02/10, ERG, added numtoflist call
  2011/02/11, ERG, changed input to be complete filename string
  2011/03/08, MWB, incorporated into the master library, minor fix on the
                     contents of the sr2 files.
  2012/03/08, MWB, added VERBOSE flag