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Collinder
In astronomy, the Collinder catalogue is a catalogue of 471 open clusters by Swedish astronomer Per Collinder. It was published in 1931 as an appendix to Collinder's paper ''On structural properties of open galactic clusters and their spatial distribution''. Catalogue objects are denoted by ''Collinder'', e.g. "Collinder 399". Dated prefixes include as ''Col + catalogue number'', or ''Cr + catalogue number'', e.g. "Cr 399". Vital statistics * The catalogue contains 471 objects: 452 open clusters, 11 globular clusters, 6 Asterism (astronomy), asterisms, 1 Stellar kinematics#Moving groups, stellar moving group, and 1 Stellar kinematics#Stellar associations, stellar association. * Objects are spread out across the entire celestial sphere. * NGC 188, Cr 8 is the northernmost Collinder object, located at a declination of +85º in the constellation Camelopardalis. * Cr 411 is the southernmost Collinder object, located at a declination of -79º in the constellation Octans. Collinder obj ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Per Collinder
Per Collinder (22 May 1890 – 6 December 1975) was a Swedish astronomer. Born at Sundsvall, he is known for a catalog of open clusters that he published in 1931, which is today known as the Collinder catalogue. He has written the books ''History of navigation'' and ''Worlds in Orbit''. He was married twice, and his first wife gave him four children. Collinder died at Uppsala Uppsala (, or all ending in , ; archaically spelled ''Upsala'') is the county seat of Uppsala County and the fourth-largest city in Sweden, after Stockholm, Gothenburg, and Malmö. It had 177,074 inhabitants in 2019. Located north of the ca .... Notes and references 1890 births 1974 deaths People from Sundsvall 20th-century Swedish astronomers {{Europe-astronomer-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asterism (astronomy)
An asterism is an observed pattern or group of stars in the sky. Asterisms can be any identified pattern or group of stars, and therefore are a more general concept than the formally defined 88 constellations. Constellations are based on asterisms, but unlike asterisms, constellations outline and today completely divide the sky and all its celestial objects into regions around their central asterisms. For example, the asterism known as the Big Dipper comprises the seven brightest stars in the constellation Ursa Major. Another is the asterism of the Southern Cross, within the constellation of Crux. Asterisms range from simple shapes of just a few stars to more complex collections of many stars covering large portions of the sky. The stars themselves may be bright naked-eye objects or fainter, even telescopic, but they are generally all of a similar brightness to each other. The larger brighter asterisms are useful for people who are familiarizing themselves with the night sky. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Octans
Octans () is a faint constellation located in the deep Southern Sky. Its name is Latin for the eighth part of a circle, but it is named after the octant, a navigational instrument. Devised by French astronomer Nicolas Louis de Lacaille in 1752, Octans remains one of the 88 modern constellations. The southern celestial pole is located within the boundaries of Octans. History and mythology Octans was one of 14 constellations created by French astronomer Nicolas Louis de Lacaille during his expedition to the Cape of Good Hope, and was originally named ''l’Octans de Reflexion'' (“the reflecting octant”) in 1752, after he had observed and catalogued almost 10,000 southern stars during a two-year stay at the Cape of Good Hope. He devised fourteen new constellations in uncharted regions of the Southern Celestial Hemisphere not visible from Europe. All but one honoured instruments that symbolised the Age of Enlightenment. It was part of his catalogue of the southern sky, the ''Co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Messier 34
Messier 34 (also known as M34 or NGC 1039) is a large and relatively near open cluster in Perseus. It was probably discovered by Giovanni Batista Hodierna before 1654 and included by Charles Messier in his catalog of comet-like objects in 1764. Messier described it as, "A cluster of small stars a little below the parallel of γ (Andromedae). In an ordinary telescope of 3 feet one can distinguish the stars." Based on the distance modulus of 8.38, it is about away. For stars ranging from 0.12 to 1 solar mass (), the cluster has about 400. It spans about 35 ′ on the sky which translates to a true radius of 7.5 light years at such distance. The cluster is just visible to the naked eye in very dark conditions, well away from city lights. It is possible to see it in binoculars when light pollution is low. The age of this cluster lies between the ages of the Pleiades open cluster at 100 million years and the Hyades open cluster at 800 million years. Specifically, comparison be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Messier 7
Messier 7 or M7, also designated NGC 6475 and sometimes known as the Ptolemy Cluster, is an open cluster of stars in the constellation of Scorpius. The cluster is easily detectable with the naked eye, close to the "stinger" of Scorpius. With a declination of −34.8°, it is the southernmost Messier object. M7 has been known since antiquity; it was first recorded by the 2nd-century Greek-Roman astronomer Ptolemy, who described it as a nebula in 130 AD. Italian astronomer Giovanni Batista Hodierna observed it before 1654 and counted 30 stars in it. In 1764, French astronomer Charles Messier catalogued the cluster as the seventh member in his list of comet-like objects. English astronomer John Herschel described it as "coarsely scattered clusters of stars". Telescopic observations of the cluster reveal about 80 stars within a field of view of 1.3° across. At the cluster's estimated distance of 980 light years this corresponds to an actual diameter of 25 light years. The tidal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Messier 48
Messier 48 or M48, also known as NGC 2548, is an open cluster of stars in the celestial equator, equatorial constellation of Hydra (constellation), Hydra. It sits near Hydra's westernmost limit with Monoceros, about to the east and slightly south of Hydra's brightest star, Alphard. This grouping was discovered by Charles Messier in 1771, but there is no cluster precisely where Messier indicated; he made an error, as he did with M47. The value that he gave for the right ascension matches, however, his declination is off by five degrees. Credit for discovery is sometimes given instead to Caroline Herschel in 1783. Her nephew John Herschel described it as, "a superb cluster which fills the whole field; stars of 9th and 10th to the 13th magnitude – and none below, but the whole ground of the sky on which it stands is singularly dotted over with infinitely minute points". M48 is visible to the naked eye under good atmospheric conditions. The brightest member is the star HIP 403 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Messier 21
Messier 21 or M21, also designated NGC 6531 or Webb's Cross, is an open cluster of stars located to the north-east of Sagittarius in the night sky, close to the Messier objects M20 to M25 (except M24). It was discovered and catalogued by Charles Messier on June 5, 1764. This cluster is relatively young and tightly packed. A few blue giant stars have been identified in the cluster, but Messier 21 is composed mainly of small dim stars. With a magnitude of 6.5, M21 is not visible to the naked eye; however, with the smallest binoculars it can be easily spotted on a dark night. The cluster is positioned near the Trifid nebula (NGC 6514), but is not associated with that nebulosity. It forms part of the Sagittarius OB1 association. This cluster is located away from Earth with an extinction of 0.87. Messier 21 is around 6.6 million years old with a mass of . It has a tidal radius of 11.7 pc, with a nucleus radius of and a coronal radius of . There are at least members with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Messier 47
Messier 47 (M47 or NGC 2422) is an open cluster in the mildly southern constellation of Puppis. It was discovered by Giovanni Batista Hodierna before 1654 and in his then keynote work re-discovered by Charles Messier on 1771. It was also independently discovered by Caroline Herschel. There is no cluster in the position indicated by Messier, which he expressed in terms of its right ascension and declination with respect to the star 2 Puppis. However, if the signs (+ and −) he wrote are swapped, the position matches. Until this equivalency was found, M47 was considered a lost Messier Object. This identification as the same thing (ad idem) only came in 1959 with a realization by Canadian astronomer T. F. Morris. M47 is centered about 1,600 light-years away and is about 78 million years old. The member stars have been measured down to about red dwarfs at apparent magnitude 19. There are around 500 members, the brightest being HD 60855, a magnitude 5.7 Be star. The cluster is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Messier 46
Messier 46 or M46, also known as NGC 2437, is an open cluster of stars in the slightly southern constellation of Puppis. It was discovered by Charles Messier in 1771. Dreyer described it as "very bright, very rich, very large." It is about 5,000 light-years away. There are an estimated 500 stars in the cluster with a combined mass of , and it is thought to be a mid-range estimate of 251.2 million years old. The cluster has a very broadest (tidal) radius of and core radius of . It has a greater spatial extent in infrared than in visible light, suggesting it is undergoing some mass segregation with the fainter (redder) stars migrating to a coma (tail) region. The fainter stars that extend out to the south and west may form a tidal tail due to a past interaction. The planetary nebula NGC 2438 appears to lie within the cluster near its northern edge (the faint almost rainbow array of colored smudge at the top-center of the image), but it is most likely unrelated since it does not ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Messier 39
Messier 39 or M39, also known as NGC 7092, is an open cluster of stars in the constellation of Cygnus, positioned two degrees to the south of the star Pi Cygni and around 9° east-northeast of Deneb. The cluster was discovered by Guillaume Le Gentil in 1749, then Charles Messier added it to his catalogue in 1764. When observed in a small telescope at low power the cluster shows around two dozen members but is best observed with binoculars. It has a total integrated magnitude (brightness) of 5.5 and spans an angular diameter of – about the size of the full Moon. It is centered about away. This cluster has an estimated mass of and a linear tidal radius of . Of the 15 brightest components, six form binary star systems; one more is suspected. HD 205117 is a probable eclipsing binary system with a period of 113.2 days that varies by 0.051 in visual magnitude. Both members seem to be subgiants. Within are at least five chemically peculiar stars and ten suspect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Messier 35
Messier 35 or M35, also known as NGC 2168, is a relatively close open cluster of stars in the west of Gemini, at about the declination of the sun when the latter is at June solstice. It was discovered by Philippe Loys de Chéseaux around 1745 and independently discovered by John Bevis before 1750. It is scattered over part of the sky almost the size of the full moon and is away. The compact open cluster NGC 2158 lies directly southwest of it. Leonard & Merritt (1989) computed the mass of M35 using a statistical technique based on proper motion velocities of its stars. The mass within the central was found to be between 1600 and 3200 solar masses, consistent with the mass of a realistic stellar population within the same radius. Bouy et al. in 2015 found a mass of around within the central . There are 305 stars that can be intrinsically shown to be extremely likely to be members, and up to 4,349 averaging the 50% membership probability, from the kinematic (such as paralla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Messier 29
Messier 29 or M29, also known as NGC 6913, is a quite small, bright open cluster of stars just south of the central bright star Gamma Cygni of a northerly zone of the sky, Cygnus. It was discovered by Charles Messier in 1764, and can be seen from Earth by using binoculars. From the solar system's viewpoint it is well within the several degrees of a certain intermittently uniquely bright and dusty plane of the night sky – that of the arms and bulge of the Milky Way. It is at least many hundreds of light years short of the yardstick distance to the galactic center, as is between 4,000Kenneth Glyn Jones (ed.) ''The Sky Catalogue 2000.0'' and 7,200 light years away.Preferred by most sources including Mallas/Kreimer and Burnham, and agreeing with early estimates or R.J. Trumpler 1930 A 1998 popular work gives a value within this range.Kepple, George Robert., Sanner, Glen W.. The Night Sky Observer's Guide: Spring & summer. United States: Willmann-Bell, 1998 at Chapter 42 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
