| Reflection nebula | |
|---|---|
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| Observation data: J2000 epoch | |
| Right ascension | 06h 31m 12.0s |
| Declination | +23° 06′ 34″ |
| Apparent magnitude (V) | 7.03 |
| Apparent dimensions (V) | ~32 arcminutes dia. |
| Constellation | Gemini |
| Designations | IC 444, DG 100, LBN 840, Ced 74. |
IC 444 is a small, 32 square arcminute reflection nebula in the constellation Gemini.
The New General Catalogue of Nebulae and Clusters of Stars is an astronomical catalogue of deep-sky objects compiled by John Louis Emil Dreyer in 1888. The NGC contains 7,840 objects, including galaxies, star clusters and emission nebulae. Dreyer published two supplements to the NGC in 1895 and 1908, known as the Index Catalogues, describing a further 5,386 astronomical objects. Thousands of these objects are best known by their NGC or IC numbers, which remain in widespread use.
Diamond dust is a ground-level cloud composed of tiny ice crystals. This meteorological phenomenon is also referred to simply as ice crystals and is reported in the METAR code as IC. Diamond dust generally forms under otherwise clear or nearly clear skies, so it is sometimes referred to as clear-sky precipitation. Diamond dust is most commonly observed in Antarctica and the Arctic, but can occur anywhere with a temperature well below freezing. In the polar regions of Earth, diamond dust may persist for several days without interruption.
Messier 108 is a barred spiral galaxy about 46 million light-years away from Earth in the northern constellation Ursa Major. It was discovered by Pierre Méchain in 1781 or 1782. From the Earth, this galaxy is seen almost edge-on.
IC 2602 is an open cluster in the constellation Carina. Discovered by Abbe Lacaille in 1751 from South Africa, the cluster is easily visible to the unaided eye, and is one of the nearest star clusters, centred about 149 parsecs away from Earth.
The Cygnus Loop is a large supernova remnant (SNR) in the constellation Cygnus, an emission nebula measuring nearly 3° across. Some arcs of the loop, known collectively as the Veil Nebula or Cirrus Nebula, emit in the visible electromagnetic range. Radio, infrared, and X-ray images reveal the complete loop.
IC 2944, also known as the Running Chicken Nebula, the Lambda Centauri Nebula or the λ Centauri Nebula, is an open cluster with an associated emission nebula found in the constellation Centaurus, near the star λ Centauri. It features Bok globules, which are frequently a site of active star formation. However, no evidence for star formation has been found in any of the globules in IC 2944. Other designations for IC 2944 include RCW 62, G40 and G42.
The Medusa Nebula is a planetary nebula in the constellation of Gemini. It is also known as Abell 21 and Sharpless 2-274. It was originally discovered in 1955 by University of California, Los Angeles astronomer George O. Abell, who classified it as an old planetary nebula. With the computation of expansion velocities and the thermal character of the radio emission, Soviet astronomers in 1971 concluded that it was most likely a planetary nebula. As the nebula is so large, its surface brightness is very low, with surface magnitudes of between +15.99 and +25 reported.
IC 5146 is a reflection/emission nebula and Caldwell object in the constellation Cygnus. The NGC description refers to IC 5146 as a cluster of 9.5 mag stars involved in a bright and dark nebula. The cluster is also known as Collinder 470. It shines at magnitude +10.0/+9.3/+7.2. Its celestial coordinates are RA 21h 53.5m, dec +47° 16′. It is located near the naked-eye star Pi Cygni, the open cluster NGC 7209 in Lacerta, and the bright open cluster M39. The cluster is about 4,000 ly away, and the central star that lights it formed about 100,000 years ago; the nebula is about 12 arcmins across, which is equivalent to a span of 15 light years.
IC 405 is an emission and reflection nebula in the constellation Auriga north of the celestial equator, surrounding the bluish, irregular variable star AE Aurigae. It shines at magnitude +6.0. Its celestial coordinates are RA 05h 16.2m dec +34° 28′. It is located near the emission nebula IC 410, the open clusters M38 and M36, and the K-class star Iota Aurigae.
NGC 935 and IC 1801 are a pair of interacting galaxies within the Aries constellation. They were discovered on 18 September 1885 by Lewis Swift. NGC 935 is the northern member of the pair, and IC 1801 is the southern. Together, they are listed in Halton Arp's Atlas of Peculiar Galaxies as Arp 276, as an example of interacting galaxies.
NGC 1893 is an open cluster in the constellation Auriga. It is about 12,400 light years away. The star cluster is embedded in the Tadpole Nebula.
IC 1011 is a barred spiral galaxy with apparent magnitude of 14.7, and with a redshift of z=0.02564 (SIMBAD) or 0.025703 (NASA), yielding a distance of 100 to 120 megaparsecs. Its light has taken 349.5 million years to travel to Earth. IC 1011's calculated age is approximately 12.95 billion years. The IC designation comes from the Index Catalogue.
NGC 156 is a double star located in the Cetus constellation. It was discovered on 1882 by Ernst Wilhelm Leberecht Tempel.
NGC 226 is a spiral galaxy located approximately 216 million light-years from the Sun in the constellation Andromeda. It was discovered on December 21, 1786, by William Herschel.
NGC 444 is a spiral galaxy of type Sd located in the constellation Pisces. It was first discovered on October 26, 1854 by R. J. Mitchell, and was also spotted on October 17, 1903 by Stéphane Javelle. It was described by Dreyer as "very faint, much extended 135°, a little brighter middle."
NGC 452 is a barred spiral galaxy located in the constellation Pisces. It was discovered in 1827 by Sir John Herschel. It is about 5 arcminutes west of NGC 444.
ESO 444-46 is a class E4 supergiant elliptical galaxy; the dominant and brightest member of the Abell 3558 galaxy cluster around 195 megaparsecs away in the constellation Centaurus. It lies within the core of the massive Shapley Supercluster, one of the closest neighboring superclusters. It is one of the largest galaxies in the local universe, and possibly contains one of the most massive black holes known. The black hole's mass is very uncertain, with estimates ranging from as low as 501 million M☉, to as high as 77.6 billion M☉.
NGC 530, also known as IC 106, is a lenticular galaxy in the constellation Cetus. It is approximately 226 million light years from the Milky Way and has a diameter of around 100,000 light years. The object was discovered on November 20, 1886, by the American astronomer Lewis A. Swift, who listed it as NGC 530, and rediscovered on November 16, 1887, by Guillaume Bigourdan, who listed it as IC 106.
IC 1953 is a barred spiral galaxy situated in the constellation of Eridanus. Located about 83.4 million light years away, it is a member of the Eridanus cluster of galaxies, a cluster of about 200 galaxies. It was discovered by DeLisle Stewart in 1899.
ESO 383-76 is an elongated, X-ray luminous supergiant elliptical galaxy, residing as the dominant, brightest cluster galaxy (BCG) of the Abell 3571 galaxy cluster, the sixth-brightest in the sky at X-ray wavelengths. It is located at the distance of 200.6 megaparsecs from Earth, and is possibly a member of the large Shapley Supercluster. With a diameter of about 540.9 kiloparsecs, it is one of the largest galaxies known. It also contains a supermassive black hole, one of the most massive known with mass estimates varying from 2 billion M☉ to 28 billion M☉.
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