The NRAO VLA Sky Survey

The NRAO VLA Sky Survey (NVSS) covers the sky north of J2000.0 delta = -40 deg (82% of the celestial sphere) at 1.4 GHz. The principal data products are (1) a set of 2326 4 deg x 4 deg continuum ``cubes'' with three planes containing Stokes I, Q, and U images plus (2) a catalog of almost 2 x 10^6 discrete sources stronger than S ~ 2.5 mJy. The images all have theta = 45" FWHM resolution and nearly uniform sensitivity. Their rms brightness fluctuations are sigma ~ 0.45 mJy beam^-1 ~ 0.14 K (Stokes I) and sigma ~ 0.29 mJy beam^-1 ~ 0.09 K (Stokes Q and U). The rms uncertainties in right ascension and declination vary from <~1" for the N ~ 4 x 10^5 sources stronger than 15 mJy to 7" at the survey limit. The NVSS was made as a service to the astronomical community. All data products, user software, and updates are being released via the World Wide Web as soon as they are produced and verified.