A typical observation at the VLA will comprise observations of a
program source interspersed with scans on nearby phase calibrators, plus
observations of a primary flux calibrator, and a bandpass calibrator
for spectral line programs. Some special considerations are needed for
observations at low and high frequencies, to deal with RFI mitigation
and bandwidth smearing (
GHz) and the effects of the troposphere and
antenna performance (
GHz).
General hints and suggestions on how to set up your VLA observations may be found in the VLA Calibration Manual
Advice specific to low and high frequency observing at the VLA may be found under "Observing Guides and Tools" at Tools for Astronomers.
Observe files tell the VLA how the whole system will be set up for each scan in an observation; JObserve is a tool for producing such observe files. For example, in the default continuum modes the outputs from JObserve for each scan are four lines ("cards") in the observe file specifying: (1) source card giving source name and other observing parameters; (2) data selection card describing integration time and IFs/channels required; (3) LO card with local oscillator settings; (4) fine tuning card with the fine tuning settings for the Fluke synthesizers. Details of other cards may be found at the VLA Operations On-Line Reference Page.
For observations that do not use the default continuum settings this cookbook assumes some familiarity with the VLA signal path. Further details may be found in the Spectral Line Users Guide.
Further information about the capabilities of the VLA may be found in the VLA Observational Status Summary.