This directory contains the IDL procedure imgrism.pro to simultaneously display
a 2-d grism image (in a .pha file) along with the extracted spectrum.    For
example, imgrism can be used with sw00336489000ugu_1.pha (GRB081203) as follows:

;Display image/spectrum on the monitor
IDL> imgrism,'sw00336489000ugu_1.pha'

;Create a postscript file sw00336489000ugu_1.ps
IDL> imgrism,'sw00336489000ugu_1.pha',/ps    

;Create a png file sw00336489000ugu_1.png
IDL> imgrism,'sw00336489000ugu_1.pha',/png

To use these procedures place them in a directory pointed to by one's !PATH (or
simply place them in the same directory as the .pha file.)   The IDL astronomy
library is also  required to be in one's !PATH.    Also needed are several
procedures (plotimage, mpfit, subcell) from Craig Markwardt's IDL library
(http://cow.physics.wisc.edu/~craigm/idl/idl.html) but they are included in this
directory.

The directory also contains IDL routines for a more customized grism extraction.
The details are not discussed here, but below are some examples using imgrism. 
 
 IDL> imgrism,'sw00336489000ugu_1.pha',/grismspec
 will show the polynomial fit to the background.
 
 IDL> imgrism,'sw00336489000ugu_1.pha',/centroid
 will follow the trace by fitting cross-dispersion profiles (not needed