file1.fits
and (if specified) file2.fits, or more.
A constant offset can be specified.
The computed sum is stored in file1.fits.
The mean flag causes the sum to be divided by the number of files. The sum is carried as a floating point number so clipping should not be a problem until the file is written.
The number of rows and columns in file1 must equal to those in filen.
The result is placed in file1 unless the outfile= option is specified.
add alflyr.fits gamma.fits
add alflyr.fits const=45 outfile=- adds 45 to the file alflyr.fits
sending the result to stdout
add gamma1.fits gamma2.fits gamma3.fits mean
-adds files gamma2.fits and gamma3.fits to gamma1.fits and divides the result by 3 and write
the result in gamma1.fits.