FITS header for 3c273.fits
FITS header for 3c273.fits
SIMPLE = T / file does conform to FITS standard
BITPIX = -32 / number of bits per data pixel
NAXIS = 4 / number of data axes
NAXIS1 = 505 / length of data axis 1
NAXIS2 = 298 / length of data axis 2
NAXIS3 = 1 / length of data axis 3
NAXIS4 = 1 / length of data axis 4
EXTEND = T / FITS dataset may contain extensions
COMMENT FITS (Flexible Image Transport System) format defined in Astronomy and
COMMENT Astrophysics Supplement Series v44/p363, v44/p371, v73/p359, v73/p365.
COMMENT Contact the NASA Science Office of Standards and Technology for the
COMMENT FITS Definition document #100 and other FITS information.
OBJECT = 'No_Name ' / Name of object
TELESCOP= 'VLA ' / Telescope used
INSTRUME= 'L-BAND ' / Instrument/detector used
OBSERVER= 'NVSS GRP' / Astronomical observer
DATE-OBS= '1995-02-27' / Date (yyyy-mm-dd) of observations
BUNIT = 'JY/BEAM ' / Physical units of image
EPOCH = 2.000E+03 / Celestial coordiate equinox
ALTRPIX = 1.000000E+00 / Frequency alternate reference pixel
DATAMAX = 4.727494E+01 / Maximum physical value in image
DATAMIN = -1.286774E-01 / Minimum physical value in image
OBSRA = 1.880000000000E+02 / Observered Right Ascension
OBSDEC = 4.000000000000E+00 / Observered declination
CTYPE1 = 'RA---SIN' / Axis types
CTYPE2 = 'DEC--SIN'
CTYPE3 = 'STOKES '
CTYPE4 = 'FREQ '
CDELT1 = -4.166667E-03 / Axis coordinate increments
CDELT2 = 4.166667E-03
CDELT3 = 1.000000E+00
CDELT4 = 1.000000E+08
CRPIX1 = 2.530000E+02 / Axis coordinate reference pixel
CRPIX2 = 4.750000E+01
CRPIX3 = 1.000000E+00
CRPIX4 = 1.000000E+00
CROTA1 = 0.000000E+00 / Axis coordinate rotation
CROTA2 = 0.000000E+00
CROTA3 = 0.000000E+00
CROTA4 = 0.000000E+00
CRVAL1 = 1.872774999996E+02 / Axis coordinate value at CRPIXn
CRVAL2 = 2.052222222222E+00
CRVAL3 = 1.000000000000E+00
CRVAL4 = 1.400000000000E+09
HISTORY ------------------------------------------------------------------------
HISTORY NRAO VLA Sky Survey
HISTORY Copyright 1994
HISTORY Associated Universities, Inc.
HISTORY National Radio Astronomy Observatory
HISTORY 520 Edgemont Road
HISTORY Charlottesville, VA 22903-2475
HISTORY
HISTORY Permission is granted for publication and reproduction of this
HISTORY material for scholarly, educational, and private non-commerical
HISTORY use. Inquiries for potential commercial uses should be
HISTORY addressed to:
HISTORY NRAO
HISTORY 520 Edgemont Road
HISTORY Charlottesville, VA 22903-2475
HISTORY
HISTORY ------------------------------------------------------------------------
HISTORY
HISTORY
HISTORY THE NRAO VLA SKY SURVEY
HISTORY
HISTORY J. J. Condon, W. D. Cotton, E. W. Greisen, and Q. F. Yin
HISTORY National Radio Astronomy Observatory, 520 Edgemont Road
HISTORY Charlottesville, VA 22903
HISTORY
HISTORY R. A Perley
HISTORY National Radio Astronomy Observatory, P. O. Box 0
HISTORY Socorro, NM 87801
HISTORY
HISTORY J. J. Broderick
HISTORY Physics Department
HISTORY Virginia Polytechnic Institute and State University
HISTORY Blacksburg, VA 24061
HISTORY
HISTORY
HISTORY Observations for the 1.4 GHz NRAO VLA Sky Survey (NVSS) began in 1993
HISTORY September and should cover the sky north of -40 deg declination (82%
HISTORY of the celestial sphere) before the end of 1996. The principal data
HISTORY products will be:
HISTORY
HISTORY (1) A set of 2326 continuum map "cubes," each covering 4 deg X 4 deg
HISTORY with three planes containing Stokes I, Q, and U images. These maps
HISTORY were made with a relatively large restoring beam (45 arcsec FWHM) to
HISTORY yield the high surface-brightness sensitivity needed for completeness
HISTORY and photometric accuracy. Their rms brightness fluctuations are
HISTORY about 0.45 mJy/beam = 0.14 K (Stokes I) and 0.29 mJy/beam = 0.09 K
HISTORY (Stokes Q and U). The rms uncertainties in right ascension and
HISTORY declination vary from 0.3 arcsec for strong (S > 30 mJy) point
HISTORY sources to 5 arcsec for the faintest (S = 2.5 mJy) detectable
HISTORY sources.
HISTORY
HISTORY (2) Lists of discrete sources.
HISTORY
HISTORY The NVSS is being made as a service to the astronomical community, and
HISTORY the data products are being released as soon as they are produced and
HISTORY verified.
HISTORY
HISTORY ------------------------------------------------------------------------
HISTORY
HISTORY
HISTORY ADDITIONAL INFORMATION
HISTORY
HISTORY All large NVSS maps that have been verified are available by anonymous
HISTORY FTP, as described below. The anonymous FTP directory also contains a
HISTORY README file pointing to files, such as the postscript file "paper.ps",
HISTORY giving a more detailed description of the NVSS. Careful users will
HISTORY read these files before using the NVSS images. If you have any
HISTORY questions or comments about the NVSS, please contact Jim Condon by
HISTORY email at Internet address "jcondon@nrao.edu" or by telephone at (804)
HISTORY 296-0322.
HISTORY
HISTORY ------------------------------------------------------------------------
HISTORY
HISTORY
HISTORY ANONYMOUS FTP DIRECTORY
HISTORY
HISTORY The large (4 deg X 4 deg) map cubes and total intensity only images
HISTORY are stored as binary files in FITS format (see Grosbol et al. 1988,
HISTORY Astronomy & Astrophysics Supplements, v. 73, p. 359 for a description
HISTORY of the FITS format). Maps are stored in gzip compressed form but an
HISTORY uncompressed form may be requested (see below). Each map is named by
HISTORY the J2000 right ascension and declination of its center. Maps
HISTORY containing the full (IQU) polarization cube have names beginning with
HISTORY a "C" and those with total intensity only begin with an "I". For
HISTORY example, C2230P84.gz is centered on right ascension = 22h 30m,
HISTORY declination = +84 deg; "M" is used to denote negative declinations.
HISTORY You can copy these maps by anonymous FTP. A typical FTP session might
HISTORY go as follows:
HISTORY
HISTORY ftp nvss.cv.nrao.edu
HISTORY login: anonymous
HISTORY password: (type your name or email address here)
HISTORY cd pub/nvss (to access the NVSS public directory)
HISTORY ls (to list the directory contents)
HISTORY get paper.ps (to get a postscript copy of the paper)
HISTORY binary (to copy binary files)
HISTORY cd MAPS (to go to the maps directory)
HISTORY get C2230P84.gz (to get the map cube centered on 22h 30m,
HISTORY +84 deg in compressed form)
HISTORY get I2230P84 (to get the total intensity map centered on
HISTORY 22h 30m, +84 deg in uncompressed form)
HISTORY quit
HISTORY
HISTORY
HISTORY You can also access the FTP directory via the VLA D-array NVSS Survey
HISTORY item on the NRAO WWW home page:
HISTORY
HISTORY http://www.nrao.edu
HISTORY
HISTORY Compression: The images are stored as standard FITS files compressed
HISTORY in GNU zip (gzip) format; the .gz at the end of the name denoting this
HISTORY compression. If an uncompressed version is desired, omit the ".gz" when
HISTORY requesting the file from ftp. Gzipped file are uncompressed using
HISTORY gunzip which is available for most computer systems. For more details
HISTORY see file pub/nvss/compress.txt.
HISTORY ------------------------------------------------------------------------
HISTORY AIPS IMNAME='I1232P04 ' IMCLASS='I ' IMSEQ= 1 /
HISTORY AIPS USERNO= 101 /
HISTORY AIPS / VDQTZ QUANTIZE AT 1.00000E-04
HISTORY AIPS CLEAN BMAJ= 1.2500E-02 BMIN= 1.2500E-02 BPA= 0.00
HISTORY AIPS CLEAN NITER= 1 PRODUCT=1 / NORMAL
HISTORY postage: Input FITS file =
HISTORY /home/ftp/pub/nvss/MAPS/I1232P04.gz
DATE = '2010-08-02' / Date FITS file written (yyyy-mm-dd)
ORIGIN = 'postage 1.2.1 (NVSS postage stamp)' / FITS file creator