identify

       images =                 Images containing features to be identified
        crval =  leave blank    Approximate coordinate (at reference pixel)
        cdelt =  leave blank    Approximate dispersion
     (section = "middle line")  Section to apply to two dimensional images
    (database = "database")     Database in which to record feature data
   (coordlist = "/astro/users/ben/premap/calibration/idhenear.dat") User coordinate list
       (units = "")             Coordinate units
        (nsum = "10")           Number of lines/columns/bands to sum in 2D imag
       (match = -3.)            Coordinate list matching limit
 (maxfeatures = 100)             Maximum number of features for automatic identi
      (zwidth = 100.)           Zoom graph width in user units
       (ftype = "emission")     Feature type
      (fwidth = 4.)             Feature width in pixels
     (cradius = 5.)             Centering radius in pixels
   (threshold = 0.)             Feature threshold for centering
      (minsep = 2.)             Minimum pixel separation
    (function = "chebychev")      Coordinate function
       (order = 1)              Order of coordinate function
      (sample = "*")            Coordinate sample regions
    (niterate = 3)              Rejection iterations
  (low_reject = 3.)             Lower rejection sigma
 (high_reject = 3.)             Upper rejection sigma
        (grow = 0.)             Rejection growing radius
   (autowrite = no)             Automatically write to database
    (graphics = "stdgraph")     Graphics output device
      (cursor = "")             Graphics cursor input
     (aidpars = "")             Automatic identification algorithm parameters
        (mode = "ql")       

NOTE:

When fititng the wavelength-pixel data, you should aim for r.m.s. residuals
less than 0.1 pixel. You should also make sure that there are no systematic
trends in the residuals and no grossly offensive outliers.

Useful Keystroke Commands:

m - mark an emission line and eneter its wavelength
f - fit the wavelength-pixel relation and display plot
l - auto-identify lines based on an approximate wavelength solution


Fitting Keystroke Commands (available when fit is displayed):

f - repeat the fit and refresh the plot
d - delete the point nearest to the cursor
j - display post-fit residuals
k - display data-to-fit ratios
l - display non-linear part of fitting function