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Starting Observations

At the start of observations, the observer needs to load the schedule file, ensure that sampler settings are in range and calibrate the array.

The Duty Astronomer should be available to help observers starting their observations

Procedure

Load the setup schedule file The schedule file for calibration needs to be loaded into caobs
caobs> set file schedule_file
Observe the calibrator In caobs, drive to the calibrator with
caobs> track # (where # is the scan number within the schedule file)
Set sampler levels Once on source, caobs should attempt to set attenuators so that the power levels into the samplers are within the sampler range. If there is insufficient range with the fine attenuators the observer may need to set coarse attenuators and occasionally even mm attenuators.
Check visibilities Once the attenuators are stable (no automatic changes for more than 1 minute) visibilities need to be checked to ensure that they are stable.
In vis, check the delays, amplitudes and phases are stable for all baselines.
cacal If visibilities are stable, continue tracking on the calibrator, and in xbones window, run cacal with
xbones> cacal
In general, it is appropriate to accept automatic mode.
amplitude calibration At some point, amplitude and bandpass calibration data needs to be observed.
For cm observations (including 1cm observations) this will (in general) be a short (5-10 min) observation on PKS1934-638.
3mm calibration is more complicated: See XXXX for information on 3mm calibration
If the calibrator is above 30 degrees at the start of the observation, it is a good time to do the calibration. If calibration cannot be done at the start, time has to be allowed at the end of the observation. To observe the amplitude calibrator:
caobs> stop stop observations
caobs> corr closefile closes the data file, another one will be opened when you start observing
(caobs> set file filename) if necessary, load a new schedule file
caobs> track # tracks on a source until the stop command
(a new data file will be opened if there isn't an open file)
caobs> stop  
start observing Finally, real observing can begin
caobs> stop  
caobs> set file filename load observation schedule file
caobs> track 1 drive to the first source in the schedule file
caobs> stop  
caobs> start 1/100 cycles through the schedule file 100 times

Original: Robin Wark (17-Aug-2006)
Modified: Robin Wark (24-Aug-2006)