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Getting NVSS data products by anonymous FTP

The large (4 deg X 4 deg) maps and their associated multisource (u,v) data sets are stored as binary files in FITS format. Maps are stored in gzip compressed form, but an uncompressed form may be requested (see below). Each map is named by the J2000 right ascension and declination of its center, and the first letter specifies the polarization plane(s). For example, C2230P84.gz is the map cube with Stokes I, Q, and U planes centered on right ascension = 22h 30m, declination = +84 deg. I0224M32.gz contains only the total-intensity plane centered on right ascension 02h 24m, declination -32 deg. The corresponding multisource (u,v) data file is called J0224-32.MS. The compressed map cubes are about 1.7 megabytes in size, and the total-intensity maps are smaller (about 0.7 megabytes) for faster access by users not interested in linear polarization. The postscript file (about 4.7 megabytes) contains a detailed description of the NVSS. This paper has been published; the reference is Condon, J. J., Cotton, W. D., Greisen, E. W., Yin, Q. F., Perley, R. A., Taylor, G. B., & Broderick, J. J. 1998, AJ, 115, 1693.

A sample anonymous FTP session is shown below:

     login: anonymous
     password:             (type your full email address here)
     cd pub/nvss           (to access the NVSS public directory)
     ls                    (to list the directory contents)
     get          (to get a postscript copy of the paper)
     binary                (to copy binary files)
     cd MAPS               (to access the MAPS directory)
     get C2230P84.gz       (to get the compressed map cube centered 
                            on 22h 30m, +84 deg)
     get I0224M32          (to get the total-intensity map centered
                            on 02h 24m, -32 deg in uncompressed form)
     cd ../CATALOG         (to go to the CATALOG directory)
     get CATALOG.FIT       (to get the source catalog as a FITS
                            binary table)

Compression: The images are stored as standard FITS files compressed in GNU zip (gzip) format, the .gz extension denoting this compression. If an uncompressed version is desired, omit the .gz when requesting the file. Gzipped files may be uncompressed with the command gunzip which is available for most computer systems. See the text file pub/nvss/compress.txt for a more detailed description of gzip.

A Romanian translation of this page was provided by Web Geek Science.

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Jim Condon