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NVSS Postage Stamp Server (2001.12.06-runs v1.2.2 of 1999.07.19)

NVSS Postage Stamp Server

This postage Stamp server for NRAO/VLA Sky Survey (NVSS) returns radio images of the sky in FITS or JPEG format, or as a contour plot. For detailed general instructions or information about this survey, see the Help File under "general"; or use the links on the forms for help about each item.

Equinox:
Polarization:
Object name [optional]:
Central Right Ascension:
Central declination:
Desired image size (degrees):
See Pixel Spacing for size limit.
Pixel spacing:
Desired pixel size in arcseconds
(Min 0.001; max image size 262144 pixels, e.g. 512 x 512)
Projection:
Desired rotation
(N through E) on the sky in degrees. (Use 0.0 for contour plots)
Image Type:
Don't use "FITS Image" unless you have an external viewer configured to activate for fits files in your browser. Also, for JPEG images, you may need to "reload" the image if you've fetched more than one.

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 0.5 mJy/beam.

the FITSview 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.

In publications using NVSS results please reference Condon, et al. 1998, AJ, 115, 1693; a preprint of this paper which describes the design and techniques of the NVSS is available here. The NVSS survey is substantially complete, missing only small, isolated holes. Entire 4 x 4 degree fields may be obtained as FITS files using either a Web browser or ftp. (Reminder: shift-click will generally force your browser to save the requested image to a file rather than displaying it in a text window.) For the latest information and detailed descriptions of the NVSS survey see its home page. An online source catalog search is also available.

Users of the AIPS task IMAGR often need to image extra fields covering nearby confusing sources. A RUN file generator produces the required list of field offsets for NVSS sources whose flux densities, attenuated by the primary beam, exceed a chosen cutoff.

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 Foundation.

Any problems with the UK postage-stamp server?

segh@mrao.cam.ac.uk