This directory contains material for running demonstrations of the routines
in the IRAF.STECF package impol

To run these demonstrations IRAF/STSDAS is mandatory and the impol package 
must be loaded

The directory is composed of the following files:

reflneb.fits      A 512x512 intensity image of a model reflection nebula

demo_foc.cl      
demo_nicmos.cl    IRAF cl scripts for running the demo's for the 
demo_wfpc2.cl     three HST instruments and a SPECIAl (non-HST)
demo_special.cl   instrument

demo_plot.cl      IRAF cl script for producing the model polarization
                  image of the instrument demo's and plotting it

For each instrument a separate file is required giving the
polarization properties for each available filter. For FOC and
WFPC2 the data in these files have been produced by integrating 
the polarization properties over the filter passband (c.f. 
Biretta & McMaster, WFPC2 Polarization Calibration, HST WFPC2
ISR 97-11). For NICMOS the values have been taken from Hines, 
Schmidt, & Schneider, 2000, Analysis of Polarized Light with 
NICMOS, PASP, 112, 983. The file for a non-HST instrument assumes 
a pefect polarizer with polarizer rotations every 22.5 degrees. 
The names of these files are as follows:

foc-pol-filt-001.tab
nicmos-pol-filt-001.tab   Required STSDAS table files for providing the
wfpc2-pol-filt-001.tab    instrumental characteristics 
special-pol-001.tab

foc-pol-filt-001.dat
nicmos-pol-filt-001.dat   ASCII data for the above STSDAS table files for 
wfpc2-pol-filt-001.dat    the instrumental characteristics 
special-pol-001.dat

define.col   Column definition file to create e.g. foc-pol-filt-001.tab
             from foc-pol-filt-001.dat
[N.B. The .tab files were created under UNIX but are not readable under
Linux and other architectures. In this case the tables files can be
recreated by running: 
tcreate table="foc-pol-filt-001.tab" cdfile="define.col" \
datafile="foc-pol-filt-001.dat" nskip=3
for example.]

reflneb.tab       STSDAS table file providing the variation of polarization
                  for the model nebula
reflnebaper3.tab  STSDAS table file providing the parameters of three
                  circular apertures for the aperture polarimetry task

reflneb.dat       ASCII data file for the above STSDAS table for the model 
                  nebula
model.col         Column definition file to create reflneb.tab from
                  reflneb.dat 
reflnebaper3.dat  ASCII data file for the above STSDAS table for the 
                  circular apertures 
aperture.col      Column definition file to create reflnebaper3.tab from
                  reflnebaper3.dat 
[N.B. The tables files can be recreated by running e.g.
tcreate table="reflneb.tab" cdfile="model.col" datafile="reflneb.dat" nskip=0 ]

demo.tar.gz       gzip'ed copy of whole contents of this directory
                  (after gunzip'ing restore with  tar xvf demo.tar)

Last updated 26 July 2000
+---------------------------------------------------------------------------+
| Jeremy R. Walsh,                                 E-mail:  jwalsh@eso.org  |
| Space Telescope European Co-ordinating Facility,                          |
| European Southern Observatory,                                  Room: 519 |
| Karl-Schwarzschild-Strasse 2,                    Phone:  +49 89 32006-248 |
| D-85748 Garching,                                FAX:    +49 89 32006-480 |
| Germany                    WWW: http://ecf.hq.eso.org/~jwalsh/jwalsh.html |
+---------------------------------------------------------------------------+