calibrate

        input =                 Input spectra to calibrate
       output =                 Output calibrated spectra
      airmass = header          Airmass
      exptime = header          Exposure time (seconds)
     (extinct = yes)            Apply extinction correction?
        (flux = yes)            Apply flux calibration?
  (extinction = "onedstds$ctioextinct.dat")   Extinction file
 (observatory = )_.observatory) Observatory of observation
   (ignoreaps = no)             Ignore aperture numbers in flux calibration?
 (sensitivity = "sens")         Image root name for sensitivity spectra
         (fnu = no)             Create spectra having units of FNU?
        (mode = "ql")           

IMPORTANT NOTES:

Keywords marked as header should be left blank so that the task can
get that information from the data header.