Galaxies & Deep Sky
Galaxies, galaxy clusters, quasars, and deep-sky objects
Astronomy: 47 Tucanae
47 Tucanae 47 Tucanae or 47 Tuc (also designated as NGC 104 and Caldwell 106) is a globular cluster located in the constellation Tucana. It is about 4.45 ± 0.01 kpc (14,500 ± 32.6 ly) from Earth, and...
Astronomy: Active Galactic Nuclei
Active Galactic Nuclei An active galactic nucleus (AGN) is a compact region at the center of a galaxy that emits a significant amount of energy across the electromagnetic spectrum, with characteristi...
Astronomy: Andromeda Galaxy
Andromeda Galaxy The Andromeda Galaxy is a barred spiral galaxy and is the nearest major galaxy to the Milky Way. It was originally named the Andromeda Nebula and is cataloged as Messier 31, M31, and...
Astronomy: Antennae Galaxies
Antennae Galaxies The Antennae Galaxies (also known as NGC 4038/NGC 4039 or Caldwell 60/Caldwell 61) are a pair of interacting galaxies in the constellation Corvus. They are currently going through a...
Astronomy: Barred Spiral Galaxies
Barred Spiral Galaxies A barred spiral galaxy is a spiral galaxy with a central bar-shaped structure composed of stars. Bars are found in about two thirds of all spiral galaxies in the local universe...
Astronomy: Blazars
Blazars A blazar (neologism of "BL Lacertae" and "Quasar") is an active galactic nucleus (AGN) with a relativistic jet – a jet composed of ionized matter traveling at nearly the speed of light – dire...
Astronomy: Cartwheel Galaxy
Cartwheel Galaxy The Cartwheel Galaxy (catalogue ESO 350-40 and PGC 2248) is a lenticular ring galaxy about 500 million light-years away in the constellation Sculptor. It has a D25 isophotal diameter...
Astronomy: Centaurus A
Centaurus A Centaurus A (also known as NGC 5128 or Caldwell 77) is a galaxy in the constellation of Centaurus. It was discovered in 1826 by Scottish astronomer James Dunlop from his home in Parramatt...
Astronomy: Cigar Galaxy
Cigar Galaxy Messier 82 (also known as NGC 3034, Cigar Galaxy or M82) is a starburst galaxy approximately 12 million light-years away in the constellation Ursa Major. It is the second-largest member ...
Astronomy: Coma Cluster
Coma Cluster The Coma Cluster (Abell 1656) is a large cluster of galaxies that contains over 1,000 identified galaxies. Along with the Leo Cluster (Abell 1367), it is one of the two major clusters co...
Astronomy: Dark Matter Halos
Dark Matter Halos In modern models of physical cosmology, a dark matter halo is a basic unit of cosmological structure. It is a hypothetical region that has decoupled from cosmic expansion and contai...
Astronomy: Elliptical Galaxies
Elliptical Galaxies An elliptical galaxy is a type of galaxy with an approximately ellipsoidal shape and a smooth, nearly featureless image. They are one of the three main classes of galaxy described...
Astronomy: Galaxy Clusters
Galaxy Clusters A galaxy cluster, or a cluster of galaxies, is a structure that consists of anywhere from hundreds to thousands of galaxies that are bound together by gravity, with typical masses ran...
Astronomy: Galaxy Mergers
Galaxy Mergers Interacting galaxies, also known as colliding galaxies, are two or more galaxies whose gravitational fields result in a disturbance of one another. There are several types of galactic ...
Astronomy: Globular Clusters
Globular Clusters A globular cluster is a spheroidal conglomeration of stars that is bound together by gravity, with a higher concentration of stars towards its center. It can contain anywhere from t...
Astronomy: Irregular Galaxies
Irregular Galaxies Irregular galaxy is a galaxy that does not have a distinct regular shape, unlike a spiral or an elliptical galaxy. Irregular galaxies do not fall into any of the regular classes of...
Astronomy: Large Magellanic Cloud
Large Magellanic Cloud The Large Magellanic Cloud (LMC) is a dwarf galaxy and satellite galaxy of the Milky Way. At a distance of around 50 kiloparsecs (163,000 light-years), the LMC is the second- o...
Astronomy: Messier 87
Messier 87 Messier 87 (also known as Virgo A or NGC 4486, generally abbreviated to M87) is a supergiant elliptical galaxy in the constellation Virgo that contains several trillion stars. One of the l...
Astronomy: NGC 1300
NGC 1300 NGC 1300 is a barred spiral galaxy located about 69 million light-years away in the constellation Eridanus. The galaxy is about 130,000 light-years across....
Astronomy: Omega Centauri
Omega Centauri Omega Centauri (ω Cen, NGC 5139, or Caldwell 80) is a globular cluster in the constellation of Centaurus that was first identified as a non-stellar object by Edmond Halley in 1677. Loc...
Astronomy: Open Clusters
Open Clusters An open cluster is a type of star cluster made of tens to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. More than 1,100 open c...
Astronomy: Pinwheel Galaxy
Pinwheel Galaxy The Pinwheel Galaxy (also known as Messier 101, M101 or NGC 5457) is a face-on, counterclockwise intermediate spiral galaxy located 21 million light-years (6.4 megaparsecs) from Earth...
Astronomy: Quasars
Quasars A quasar ( KWAY-zar) is an extremely luminous active galactic nucleus (AGN). It is sometimes known as a quasi-stellar object, abbreviated QSO....
Astronomy: Sagittarius A*
Sagittarius A* A* or A star may refer to: A* search algorithm, a pathfinding algorithm used in computing A*, the highest grade in some examination systems such as the GCE Advanced Level A*STAR, the ...
Astronomy: Small Magellanic Cloud
Small Magellanic Cloud The Small Magellanic Cloud (SMC) is a dwarf galaxy near the Milky Way. Classified as a dwarf irregular galaxy, the SMC has a D25 isophotal diameter of about 5.78 kiloparsecs (1...
Astronomy: Sombrero Galaxy
Sombrero Galaxy The Sombrero Galaxy (also known as Messier Object 104, M104 or NGC 4594) is a peculiar galaxy of unclear classification in the constellation borders of Virgo and Corvus, being about 9...
Astronomy: Spiral Galaxies
Spiral Galaxies Spiral galaxies form a class of galaxy originally described by Edwin Hubble in his 1936 work The Realm of the Nebulae and, as such, form part of the Hubble sequence. Most spiral galax...
Astronomy: The Local Group
The Local Group The Local Group is the galaxy group that includes the Milky Way, where Earth is located. It consists of two collections of galaxies in a "dumbbell" shape; the Milky Way and its satell...
Astronomy: The Milky Way
The Milky Way The Milky Way or Milky Way Galaxy is the galaxy that includes the Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky f...
Astronomy: The Pleiades
The Pleiades The Pleiades ( PLEE-ə-deez, PLAY-, PLY-), also known as Seven Sisters and Messier 45 (M45), is an asterism of an open star cluster containing young B-type stars in the northwest of the c...
Astronomy: Triangulum Galaxy
Triangulum Galaxy The Triangulum Galaxy is a spiral galaxy 2.878 million light-years (ly) from Earth in the constellation Triangulum. It is catalogued as Messier 33 or NGC 598....
Astronomy: Virgo Cluster
Virgo Cluster The Virgo Cluster is a cluster of galaxies whose center is 53.8 ± 0.3 Mly (16.5 ± 0.1 Mpc) away in the Virgo constellation. Comprising approximately 1,300 (and possibly up to 2,000) mem...
Astronomy: Whirlpool Galaxy
Whirlpool Galaxy The Whirlpool Galaxy, also known as Messier 51a (M51a) or NGC 5194, is an interacting grand-design spiral galaxy with a Seyfert 2 active galactic nucleus. It lies in the constellatio...