. This section describes how to convert raw correlator data to our standard archive format. From there is it relatively easy to obtain either arrival times or to study polarization. The data reduction is a multistage process. You must learn about each in turn. Note: production and reduction of the correlator data uses the environment variables OBSDATA, OBSDIR, and fptmpool a lot. Booking is in OBSDIR, data goes into OBSDATA and the finished archives end up in fptmpool. (You need a $ sign in front of them) .