TRIPP_CHEESE_FLAT

      Generate image excluding all stars found in input image

      photometry

       TRIPP_CHEESE_FLAT, IMAGE, FWHM=FWHM, DETECT_SIGMA=DETECT_SIGMA, $
                 GAIN=GAIN, RON=RON, REL_ERR=REL_ERR, CUT_VAL=CUT_VAL

        IMAGE - 2-dimensional array which should be checked against
                stars etc.

        FWHM : Full width half maximum of gauss function to be used
               for search. Determines size of stars to be
               excluded. Defines also circle which is cut from image
               by CUT_RAD=2*FWHM if CUT_RAD is not defined.
               Default: 10
        DETECT_SIGMA: Detection statistic threshold. All stars below
               this sigma are ignored.
               Default: 3
        GAIN:  Ratio of photons (electrons) used per ADU (i.e. value
               stored in image). Used to determine background random
               noise.
               Default: 2.60 e-/ADU (CAHA instrument)
        RON:   Readout noise in units of photons (electrons). Used to
               determine background random noise.
               Default: 5.980 (CAHA instrument)
        REL_ERR: Relative error defining background noise. The
               noise is determined at first step for one pixel
               only. To get the proper noise to set the detection
               threshold the algorithm must adjust the error with
               a relative error factor. This factor is print out by
               the DAO-PHOT FIND routine but unfortunately could not
               be used for automatic processing. Refer also: DAOPHOT
               2 Manual, Annex 2, and P.R.Stetson.
               Default: 1
        CUT_RAD: Radius of circle to cut from image.
               Default:  2*FWHM.
        CUT_VAL: Value to set image circle at.
               Default = 0.

        IMAGE - input image with all found stars excluded (set at CUT_VAL)

        Destroys input image by changing pixel values for found stars.

        Could not find extended star sources.

        > img=readfits("flat3.fits")
        > TRIPP_CHEESE_FLAT, img, 10, 5, 2.6, 5.98, 0.45
        > tripp_tv, img
     -> exclude stars from img, fwhm of 10 -> radius = 20,
     -> detection sigma of 5 with relative error of 0.45,
     -> detector properties of gain 2.6 and readout noise of 5.98
        (e-).

     created 21-09-2001, Eckart Göhler

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