Troposphere calibrators for VLBA Calibrator Survey observing sessions

In addition to observing target objects, 3-4 strong sources from the troposphere calibrator list were observed every 1-1.5 hours during observing VLBA Calibrator Surveys VCS2, VCS3, VCS4 and VCS5 sessions. They were scheduled in such a way, that at each VLBA station at least one of these sources was observed at an elevation angle less than 20o, and at least one at an elevation angle greater than 50o. The purpose of these observations was to provide calibration for mismodeled atmospheric path delays and to tie the VCS source positions to the ICRF catalogue Ma et al. 1998. The list of troposphere calibrators was selected among the sources which according to the 2cm survey results Kovalev et al. 1998 showed the compactness index, i.e. the ratio of the flux density of an unresolved detail to the total VLBA flux density, more than 0.5. The coordinates of these sources are taken from the astrometric and geodetic catalogue RFC.

The troposphere calibrator list

Catalogue of 155 sources which forms the pool of tropospheric calibrators.

The same source list in VLBA SCHED key-file format.


  1. Ma, C., Arias, E.F., Eubanks, T.M., Fey, A.L., Gontier, A.-M., Jacobs, C.S., Sovers, O.J., Archinal, B.A., and Charlot, P., 1998, The International Celestial Reference Frame as Realized by Very Long Baseline Interferometry, Astronomical Journal, 116, 516
  2. Kovalev, Y.Y., Kellermann, K.I., Lister, M.L., Homan, D.C., Vermeulen, R.C., Cohen, M.H., Ros, E., Kadler, M., Lobanov, A.P., Zensus, J.A., Kardashev, N.S., Gurvits, L.I., Aller, M.F., and Aller, H.D. 2005, Sub-milliarcsecond Imaging of Quasars and Active Galactic Nuclei. IV. Fine Scale Structure, Astronomical Journal, 130, 2473. (astro-ph/0505536)

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This page was prepared by Leonid Petrov ()
Last update: 2017.06.20_11:15:49