WRT_FITS creates a FITS file from an image (data) by typing: IDL> wrt_fits, outfil, header, data(*,*,n) where outfil is the string containing the filename. header is optional input which is the FITS string array ASCII header. If it is undefined, then WRT_FITS will build the minimal header. The routine RFITS should be used to read it. For SXT data, we recommend that you use SXT2FITS which is described in the next section.