JObserve uses standard Calibrator Lists and NRAO Default Lists available from NRAO. The Databases menu allows you to check whether the versions you are using are the same as the most recent NRAO versions, and if you have old versions, to download the most up-to-date databases. On starting JObserve the Calibrator List displays all sources in the VLA Calibrator Manual.
You may restrict the calibration sources displayed to those near a source in your Source List or Observe List by highlighting the item (single click) and selecting Find nearby calibrator in the Databases menu. The distance from the source selected to the calibrators in the Calibrators List is then also given in degrees.