iraf.net

Hi,I am trying to create cosmic ray masks using the task driz_cr within the dither package.
To do that, I need to specify the image group to be cleaned, however my file does not contain multi groups.I try to give group=1, but I get the following message:Working on image.fits
ERROR: FXF: EOF encountered while reading FITS file (image.fits[1])
"imgets(inimg,backg)"
line 79: dither$driz_cr.cl
called as: `driz_cr (inlist=image.fits, gain=0.8, rn=2.7, SNR=3)'

If I give the commands catfits image.fits this is what I get:EXT# FITSNAME FILENAME EXTVE DIMENS BITPI OBJECT 0 image.fits 2048x1034 16 NGC1705 How can I solve the problem?hope somebody can help!
thanks!Francesca

Try using parameter 'group=0' if you have a simple FITS file. Otherwise, you can have a look at the CRUTIL package. The STScI helpdesk (help@stsci.edu) might also be able to offer some advice.