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Up: Observing Guide for Pulsars
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This process can now be achieved under computer control (either by the
controller or observer).
- Ask the controller to give control of the telescope to arthur,
if it is not already.
- Stop any current integration.
- If you wish the controller to run offset scans, he should start the
PSRCONTROL program in the usual way for timing, then select
OFFSETS from the main menu.
- If you wish to run the program yourself, log in to ARTHUR as PULSAR (or a
pulsar group account) and
type OFFSET1. The procedure is now the same for observer or
- Configure the scan routine from the OFFSET startup menu. In general the
default values are recommended and you should only need to select a
- Decide whether to make initial scan in Azimuth or Elevation (this item toggles if you
- Select a source. (Hit return to be presented with a list of calibration
sources, move the cursor to the source you want and hit
RETURN, Press ENTER to continue).
- For a strong calibrator, you can add extra attenuation (type in an integer
number of dBs, press RETURN).
- Change the parameter file if necessary (default is recommended).
- Optionally choose a graphics device for a pretty printout.
- Check initial az and el offsets (these are taken from the PSRACQ parameter
file.) Check length of scan, offset rate and errors
tolerance. (Default values are recommended).
- Auto reverse scan can be toggled ON or OFF (Default will scan in both
Azimuth and elevation, forward and reverse)
- ENTER to start scanning, CTRL-Z to chicken out.
- The program will make two scans along the initial scan axis, measuring
signal levels (on both polarisations summed) through the Pulsar timing
hardware (filter bank and DDU)
- A gaussian is fit to the scans and the axis offset is set to the value
- two furthur scans are made and fitted along the other axis.
- Offset values are given and can be noted down as the program progresses,
but more accurate values can be obtained after the scans are finished, by
running PLOTOFFSET 1. This process incorporates some spike
rejection, and produces a graphics output for posterity.
- File the offset graph in the Pulsar calibration folder, note the values in
the log book and update the default parameter file using MENU
Sun Aug 17 17:32:08 BST 1997
Mod: Oct 21 1999 cajordan