NRAO VLA Sky Survey
The NRAO VLA Sky Survey ( NVSS ) was an astronomical survey of the Northern Hemisphere carried out by the Very Large Array ( VLA ) of the National Radio Astronomy Observatory ( NRAO ) , resulting in an astronomical catalogue . 
<triplet> NRAO VLA Sky Survey <subj> astronomical survey <obj> instance of <triplet> astronomical survey <subj> astronomical catalogue <obj> subclass of <triplet> Very Large Array <subj> NRAO VLA Sky Survey <obj> part of <subj> National Radio Astronomy Observatory <obj> operator <triplet> National Radio Astronomy Observatory <subj> Very Large Array <obj> has part