Note on Calibrators for the LBA

Basically there are two kinds of (total flux) calibrators in VLBI:
    FRINGE FINDERS: which are strong sources near the source of interest to estimate delay and rate errors due to correlator model errors other than source position. Particularly handy to correct large clock errors.

    PHASE REFERENCING: where observations of a calibrator source are interleaved with those of the target. Then fringe fit solutions for the calibrator source can be used to calibrate delay, rate and phase residuals of the target.

LBA staff will help you with this when preparing the observing schedule with you. Meanwhile the following resources provide useful information about potential calibrators: Note 1: Sources marked as "C" (calibrators) are safe for using as phase calibrators and fringe finders (if they are bright enough). Sources marked as "N" (non-calibrators) may be suitable as calibrators caution if additional information is available. Sources marked as "U" (unreliable) should not been used as calibrators without additional observations.

Note 2: Many sources are variable and exhibit changes in their structure.

Updated 2010.jun.04