Strange things -- Open questions

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NVis count in listobs

  • The number of visibilities corresponding to a given integration does not take into account neither the number of channels nor the number of polarizations. 1 spectral window and 1 baseline and 1 integration = 1 visibility
  • The auto-correlations are regarded as visibilities: N antennas correspond to N*(N-1)/2 baselines and {N*(N-1)/2}+N visibilities.

Example [NGC3256]: 1 integration, 9 antennas (36 baselines), 4 spectral windows (of 128,128,1,1 channels and 2 polarizations) => NVis=180

  • In the case of the WVR data (i.e. one of the spectral window), N antennas correspond to NVis=N (no correlation). And sometimes 2 separate integrations are put together in the listobs (NVis=2*N in that case). This is strange. [found in NGC3256 dataset from CSV]