MK_SFD creates a desaturated set of images
from a series of long and short exposures by typing:
IDL> mk_sfd,infil,outfil,filpref
where 
is a string array of one or more SFR filenames (and
locations), 
is the string array containing the name of directory
where you want the file to be created, and 
is a string array
which contains the three letter file prefix name (usually SFD). The
desaturated image is compressed such that:
0 = 1 dn/sec/5 arcsec pixel
255 = 1,000,000 dn/sec/5 arcsec pixel
Use the routine SFD_DECOMP to restore the data from compressed bytes
to real numbers.