Definition of Duplicate Observation

A proposed observation is considered a duplicate of another observation if all of the following conditions are met:

  • Target field location
    • For a single-field, the proposed position coincides within the half-power beam width of the
      other observation. Moving objects (e.g., Solar System objects) will be identified by name.
    • For mosaic observations, more than 50% of the proposed pointings are within the half-power beam width area covered by the other observation.
    • For evolving or variables sources, the duplication is not scientifically justified.
    • For GBT monitoring programs, no two active programs can monitor the same proposed position that coincides within the half-power beam width of the other observation. Moving objects (e.g., Solar System objects) will be identified by name.
  • Angular Resolution
    • The proposed angular resolution differs by a factor of ≤ 2 from the other observation.
  • Spectral Windows
    • For the VLA and VLBA,
      • Continuum: The requested sensitivity (rms) for the aggregate bandwidth is better by a factor of ≤ 2 from the other observation and the requested frequency is within a factor of 1.3.
      • Spectral line: If the central frequency in any requested correlator window is encompassed by the other observation and the sensitivity per spectral channel, after smoothing to the same spectral resolution, is better by a factor of ≤ 2. Or, if the spectral resolution, as justified by the science case, is better by a factor of ≤ 2.
    • For the GBT,
      • Continuum: The requested sensitivity (rms) for the aggregate bandwidth is better by a factor of ≤ 2 from the other observation and the requested frequency is within a factor of 1.3.
      • Spectral Lines: Within the largest beam size of two receivers with overlapping frequency ranges, any spectral line being the same while taking into account velocity/redshift.

Solar observations will not be checked for duplication.

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