Once setup is complete, science observations can begin. Observations need to include calibration data, including data for flux density, bandpass, polarisation and gain calibration.
It is important that sufficient calibration data is taken to characterise the array. This means taking flux density and bandpass calibration data for all observations, and leakage calibration data for polarisation observations.
This does not have to be done at the start of the observation, but should be done at some point during the observing session. If appropriate calibration sources are not above the horizon during the observing session, contact the scheduler (Jamie Stevens) to discuss options.
For cm, 15mm and 7mm observations, PKS1934-638 is the
appropriate flux calibrator and can also usually be used as a bandpass
calibrator (although spectral line observations at 15mm or 7mm will ordinarily require a stronger source).
For 3mm observations, a planet is needed for flux calibration, and a
source with large flux density (e.g. PKS1921-293 or PKS1253-055)
is required to calibrate the bandpass.
Bandpass calibrators should ideally be observed at high elevation (above 40 degrees) if possible. This is especially important for excellent polarization calibration.