response

  calibration = input image name  Longslit calibration images
 normalizatio = input image name  Normalization spectrum images
     response = output image name Response function images
 (interactive = yes)            Fit normalization spectrum interactively?
   (threshold = INDEF)          Response threshold
      (sample = "*")            Sample of points to use in fit
    (naverage = 1)              Number of points in sample averaging
    (function = "spline3")      Fitting function
       (order = 30)              Order of fitting function
  (low_reject = 3.)             Low rejection in sigma of fit
 (high_reject = 3.)             High rejection in sigma of fit
    (niterate = 1)              Number of rejection iterations
        (grow = 0.)             Rejection growing radius
    (graphics = "stdgraph")     Graphics output device
      (cursor = "")             Graphics cursor input
        (mode = "ql")           

Useful cursor keys in graph mode:

f - repeat the fit and redray the graph (after fitting function 
    parameters have been changed)

k - display ratio of data to fit (use this version of the plot 
    gauge the goodness of the fit; residulas should be around 15%)

j - display original data with fit superposed

? - get the help menu

Useful :commands in graph mode:

:function <name> - change the type of fitting function (<name> =
                   chebychev, legendre, spline1, spline3)

:order N         - change the order of the fitting function (N=order)