NASA/IPAC Extragalactic Database

The NASA/IPAC Extragalactic Database (NED) is an online astronomical database that organizes positions, redshifts, photometry, and literature references for objects beyond the Milky Way.

Astronomical object: A physical entity or structure studied in astronomy, such as a star, galaxy, or nebula. NED gathers records for astronomical objects, concentrating on those outside the Milky Way.
Celestial coordinate system: A framework for specifying positions on the celestial sphere using angular coordinates. NED uses celestial positions to identify and locate objects.
Virtual Observatory: An approach to astronomy that enables interoperable access to distributed data and services. NED participates in the broader effort to make astronomical data accessible across archives.
NASA: The United States government agency responsible for the civilian space program and aerospace research. NASA is one of the institutions named in NED’s title and supports its operation.
Astronomical catalog: An organized list of astronomical objects with identifying information and measured properties. NED brings together object data drawn from many catalogs.
Equatorial coordinate system: A celestial coordinate system that specifies positions by right ascension and declination. Right ascension and declination are common position fields in NED records.
International Virtual Observatory Alliance: An international organization that coordinates standards for sharing astronomical data and services. Its standards support interoperable access to resources such as NED.
Infrared Processing and Analysis Center: A NASA astronomy and data center at the California Institute of Technology. IPAC hosts and operates NED as part of its astronomical data services.
Astronomical cross-identification: The process of determining whether observations or catalog entries describe the same celestial object. NED links differently named records when they identify the same extragalactic object.
Galaxy: A gravitationally bound system of stars, gas, dust, and dark matter. Galaxies are a central class of extragalactic objects represented in NED.

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