THE VLA CONTINUUM POLARIMETRY DATA SET: 3C129
                            (Greg Taylor)

    These observations were taken with the VLA in the B-configuration
at 6 and 3.6 cm on July 25, 1994.  They were part of a multi-configuration,
multi-frequency project to provide high resolution images with good
sensitivity for this interesting source.  Polarimetry was particularly
important as one of the goals was to study the Faraday rotation 
measures in 3C129.  Results were published by Taylor, G.B., Govoni, F., 
Allen, S.W., and Fabian, A.C. 2001, MNRAS, 326, 2, astro-ph/0104223
"Magnetic Fields in the 3C129 Cluster".

    The data reduction for this project can be divided into three
stages - (1) calibrating the raw multi-source VLA data; (2)
self-calibrating the source data; and (3) making total intensity and
polarization images of the fully calibrated data.

Stage 1.  Calibrating 
---------------------
The multi-source file AT166.XBAND contains observations at 8 GHz of
the absolute flux density calibrator (0134+329=3C48), the absolute
polarization angle calibrator (0518+165=3C138) the phase calibrator
(0420+417), the polarization calibrator (0420+417), and 3C129.  There
are 2 IFs, 8515 and 8885 MHz, each with both right and left circular
correlator products.  The data have not been flagged or processed in
any way.  There is a similar file for the 5 GHz data in AT166.CBAND.

Stage 2. Imaging
----------------
If you have trouble getting the data calibrated, or want to skip that
step you can find calibration tables in AT166.XTAB and AT166.CTAB.
Once the tables are attatched you can SPLIT the sources out and
proceed with imaging and self-calibration.

Stage 3. Analysis
-----------------
The task IMAGR can be used to produce Stokes I, Q, U (and if you want
- V) images.  The task COMB can then be used to make images of the
linearly polarized intensity and polarization angle.  Try out PCNTR to
make contour plots with polarization vectors superposed.  If you process
more than one frequency to completion then you can make a primative
rotation measure image with COMB as well.  

Have fun!
                       - Greg