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Calibrate the System Temperature


  1. Ask the controller to give control of the telescope to arthur, if it is not already.
  2. Stop any current integration.
  3. If you wish the controller to do the calibration, he should start the PSRCONTROL program in the usual way for timing, then select CALIBRATE from the main menu.
  4. If you wish to run the program yourself, log in to ARTHUR as PULSAR (or a pulsar group account) and type PSRCAL1. The procedure is now the same for observer or controller.
  5. If you have just checked the telescope offsets Sec. 5Make sure that the parameter file is updated and set as default.
  6. Choose a source that has a flux density comparable to the system temperature Ssys. Expected Ssys and cal levels are shown in Table 1.
  7. Try to choose a source as far away as possible from the sun (at least 90) and the Galactic plane.
  8. A high elevation is also desirable to avoid ground spillover effects (Figure 5

    Figure 5: The lower solid curve shows spill over at 1400MHz for the Lovell telescope.

    Table 4: Calibration sources. # Indicates preferred sources

  9. When selecting whether to make the offsets in RA or DEC, select the coordinate that will make most of the offset occur in azimuth rather than elevation. The telescope settles more quickly in azimuth than elevation, and this avoids variable ground effects during the calibrations procedure.
  10. If a strong source has had to be chosen and you are worried about saturation, extra attenuation can be added to the entire calibration run.
  11. The program will perform 6 sets of 4 integrations.
  12. Print out the result and stick it into the pulsar calibration folder. Make a note of the values in the log book.
  13. You are now ready to start observing. Ask the controller to start up psrcontrol and start off on a strong pulsar to check that you see pulses.
  14. You should also note the details of the filter banks, local oscillators and frequency of channel 1 in the logbook.

Jon Bell
Sun Aug 17 17:32:08 BST 1997
Mod: 21 Oct. 1999 cajordan