The number of pixels expected to be contaminated by cosmic rays. (Only used when cosmic-ray checking is enabled by TUNE_CRTRC=TRUE.)
This may be estimated by the user, or be generated by an automatic modeller.
If no estimate is available, then zero should be used. The program will then display a histogram of the ratio of original divided-by median image and allow manual selection of a clipping point. The number of pixels to be clipped (flagged as cosmic rays) will then be shown.
Martin Clayton