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 gamma
add alflyr const=45 outfile=- adds 45 to the file alflyr.fits
sending the result to stdout
add gamma1 gamma2 gamma3 mean
-adds files gamma2 and gamma3 to gamma1 and divides the result by 3 and write
the result in gamma1.fits.