Pipeline: Frequent VLA problems

General Description The VLA pipeline delivers calibrated data and some initial images of VLA observation runs. The quality of the calibration and imaging products is usually assessed through the weblog that is created in each pipeline run. During the observations, the VLA may have encountered technical problems that are reflected in various ways in the weblog, analytic graphs show the behavior of the calibration tables as a function of time, frequency, polarization, etc. Analytical numbers describe the amount of flagging, derived fluxes, image statistics, etc.

Here we would like to briefly describe common VLA observing problems, how they are identified in the pipeline calibration weblog, and how they can be addressed.

Pointing

RFI Deformatter Problems

Correlator Zeros

Baseband and Subband Edges

Compression

Resolved Calibrators

Wrong Intents

Extreme Solution Intervals

Weather

Decorrelation

Shadowing

Switches