.help crcombine Apr98 noao.imred.crutil
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NAME
crcombine -- combine multiple exposures to eliminate cosmic rays
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USAGE	
.nf
crcombine input output
.fi
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PARAMETERS
See parameters for \fBimcombine\fR.
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DESCRIPTION
This task is a version of \fBimcombine\fR.  See the help for that task
for a description of the parameters and algorithms.

For the purpose of removing cosmic rays the most useful options
are the "crreject" algorithm and/or combining with a median.  Many other
options may work as well.  The best use of this task depends on the
number of images available.  If there are more than a few images the
images should be combined with an "average" and using a rejection
algorithm.
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EXAMPLES
1.  To combine two images using the gain and read noise parameters in
the image header:

.nf
    cl> crcombine obj012,obj013 abc gain=gain rdnoise=rdnoise 
.fi
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SEE ALSO
imcombine
.endhelp
