CHAPTER 4: Data reductionThis chapter explains how to start reducing the baseband data that is recorded to the cluster disks. This is accomplished through another graphical user interface, GUIManager.
Section 1: PSRDISPThe program that is responsible for taking baseband data and coherently de-dispersing it into archives of folded profiles is called psrdisp. It is smart enough to access the pulsar catalogue on the cluster nodes to obtain an ephemeris for any baseband file it is directed to, based on the source name in the header. The processing parameters that are used are set when you launch a batch job from the GUIManager. This will suggest a default set of parameters for each job. Be aware that these may not always be the best! In particular, any "-x" options should be removed when processing 50 cm data.
The GUIManager takes the folded archives and moves them to a central store where they are sorted by source name and UTC start time. Normally the baseband data is deleted after processing, but it is possible to override this behaviour using a check-box on the GUI. Be aware that the cluster disks can only hold about 8 hours of data (when completely empty) so it is usually essential to process and delete the raw data files to prevent the disks filling. To kick off data reduction, run GUIManager on one of the secondary nodes. Wait for the ObsID of your observation to show up in the list of baseband files. Highlight it with the mouse and press the PSRDISP button. Enter the processing parameters to use and hit "OK". This will launch a cluster wide batch job.
Section 2: Real Time Data MonitoringYou can watch your data as it comes in (usually in chunks of 16 seconds) using the program ObsMonitor. This program must be run on cpsr1 and it takes a single argument which is the band number (0 or 1) to watch. In order to see both bands you must run two copies of the program (both on cpsr1).