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VLSSr postage stamp server
The VLA Low-Frequency Sky Survey Redux (VLSSr)
VLSS-Redux Postage Stamp Server
The National Radio Astronomy Obseratory (NRAO) and
the Naval Research Laboratory
(NRL) used the NRAO Very Large Array to survey the sky north of a
declination of -30 degrees at a frequency of 74 MHz.
This postage stamp server is for images from a re-reduction of the survey
data (VLSSr), with maps at a resolution of
75" and a limiting peak source brightness of about 500 mJy/beam.
Final sky coverage of the catalog and images is complete above -10
degrees declination, and extends down to -30 degrees declination at
most RAs. In some areas data is available down to declinations of -36
The VLSSr represents a major improvement to the original VLSS over
most of the sky. It includes six previously unpublished fields, and
improved dynamic range in 95% of all fields. The clean bias has been
halved and is now 0.66 times the local RMS. The largest angular size
imaged has been roughly doubled to 36', and the number of cataloged
sources is increased by 35% to %93,000.
An improved primary beam model was applied to correct substantial
radially dependent flux errors present in the VLSS.
The VLSSr maps and catalog use the Roger, Costain and Bridle (1973 AJ
78 130) flux scale, based on the source models presented in Scaife and
Heald (2012 MNRAS 423 30).
If you make use of VLSSr data in your work, please reference this paper:
Lane, W. M., Cotton, W. D., Helmboldt , J. and Kassim, N. E. 2012
"VLSS Redux: Software Improvements applied to the Very Large Array
Low-frequency Sky Survey", Radio Science v. 47, RS0K04
For detailed general instructions click
here or for more about a form entry
click on its label.
Note: The southern completeness limit is -10 degrees for 18h < RA < 21h, -20 degrees for 15h < RA < 18h, and -30 degrees for the rest of the sky, with decreasing sky coverage to -36 degrees.
Note: these images will have a relatively high dynamic
range which will cause them to appear as white dots on a black background
unless the viewer used has suitable control over brightness, contrast and
the range of values to be displayed. The "noise" level in these images is
about 100 mJy/beam.
family of FITS image viewers is available for a variety of computer
systems. For a short discussion of installing external viewers for FITS
files click here.
Entire 17 x 17 deg fields can be obtained
or through a
simplified form interface.
The entire source catalog as a FITS binary table and software is available
(Reminder: shift-click will generally force your browser to save the requested
image to a file rather than displaying it in a text window.)
A postage stamp server is also available to obtain FITS images, jpeg or
contour plots of smaller regions. Ionospheric climatology using the VLSSr is described
The original survey reduction products (VLSS) can be obtained
The original survey (VLSS) is documented in: Cohen, A. S., Lane, W. M.,
Cotton, W. D., Kassim, N. E., Lazio, T. J., Perley, R. A. Condon, J.,
Erickson, W. C. 2006. "The VLA Low Frequency Sky Survey: Methods and
Preliminary Results", 2007, AJ, 134, 1245-1262
Other Sources of FITS Images from Sky Surveys
The (USA) National Radio Astronomy Observatory
(NRAO) is operated by
Associated Universities, Inc. and is a
Facility of the (USA) National Science
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