NED is a comprehensive database of multiwavelength data for extragalactic objects, providing a systematic, ongoing fusion of information integrated from hundreds of large sky surveys and tens of thousands of research publications. The contents and services span the entire observed spectrum from gamma rays through radio frequencies. As new observations are published, they are cross- identified or statistically associated with previous data and integrated into a unified database to simplify queries and retrieval. Seamless connectivity is also provided to data in NASA astrophysics mission archives (IRSA, HEASARC, MAST), to the astrophysics literature via ADS, and to other data centers around the world.
NASA/IPAC Extragalactic Database is covered by SCOPUS. NED's data and references are being continually updated, with revised versions being put on-line every 4-6 months.
NED contains "Level 5" a knowledgebase for extragalactic astronomy and cosmology