|U.S. Naval Observatory
The Radio Reference Frame Image Database
- VLBA Images -- `snapshot' images
made using the National Radio Astronomy Observatory (NRAO) Very Long Baseline Array
telescope. Images using the VLBA together with several geodetic
antennas are also available for some sources. These 'VLBA+' images
provide enhanced uv-plane coverage and up to twice the
resolution of the VLBA alone. Available items include contour plots
and visibility plots in PostScript format. Images and/or visibility
data can also be obtained in FITS format upon request.
- Geodetic VLBI
Images -- `snapshot' images made using geodetic and/or
astrometric Very Long Baseline Interferometry (VLBI) observations.
Available items include contour plots in PostScript format.
The data presented here are the result of an ongoing program to
image radio reference frame sources on a regular basis. Our goal is to
establish a database of images of all of radio reference frame sources
at the same wavelengths as those used for precise astrometry (13cm and
4cm). These data will allow us primarily to monitor sources for
variability or structural changes so they can be evaluated for
continued suitability as radio reference frame objects. Further
information concerning these data can be found in the following
Observations of Radio Reference Frame Sources. I.,"
Astrophysical Journal Supplement Series, August 1996 issue (Vol. 105,
No. 2, Pages 299-330).
Observations of Radio Reference Frame Sources. II. Astrometric
Suitability Based on Observed Structure,"
Journal Supplement Series, July 1997 issue (Vol. 111, No. 1, Pages
Observations of Radio Reference Frame Sources. III. Astrometric
Suitability of an Additional 225 Sources,"
Journal Supplement Series, May 2000 issue (Vol. 128, No 1, Pages
If you make use of these data in any publication, please refer
to the citation instructions.
VLA and VLBI images of many of these sources may also be obtained
from the Pearson-Readhead
and Caltech-Jodrell Surveys. See also the VLBA Calibrator Survey
and the VLBA 2cm
Last modified: Wed Jun 13 09:44:52 EDT 2001
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