Messier object
Encyclopedia
The Messier objects are a set of astronomical object
Astronomical object
Astronomical objects or celestial objects are naturally occurring physical entities, associations or structures that current science has demonstrated to exist in the observable universe. The term astronomical object is sometimes used interchangeably with astronomical body...

s first listed by French
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

 astronomer
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...

 Charles Messier
Charles Messier
Charles Messier was a French astronomer most notable for publishing an astronomical catalogue consisting of deep sky objects such as nebulae and star clusters that came to be known as the 110 "Messier objects"...

 in 1771. The original motivation of the catalogue was that Messier was a comet
Comet
A comet is an icy small Solar System body that, when close enough to the Sun, displays a visible coma and sometimes also a tail. These phenomena are both due to the effects of solar radiation and the solar wind upon the nucleus of the comet...

 hunter, and was frustrated by objects which resembled but were not comets. He therefore compiled a list of these objects, in collaboration with his assistant Pierre Méchain
Pierre Méchain
Pierre François André Méchain was a French astronomer and surveyor who, with Charles Messier, was a major contributor to the early study of deep sky objects and comets.-Life:...

.

A similar list had been published in 1654 by Giovanni Hodierna
Giovanni Battista Hodierna
Giovanni Battista Hodierna was an Italian astronomer at the court of the Duke of Montechiaro. He compiled a catalog of some 40 entries, including at least 19 real and verifiable nebulous objects that might be confused with comets. The work anticipated Messier's catalogue, but had little impact...

, but had no impact and was probably not known to Messier.

Lists and editions

The first edition covered 45 objects numbered M1
Crab Nebula
The Crab Nebula  is a supernova remnant and pulsar wind nebula in the constellation of Taurus...

 to M45
Pleiades (star cluster)
In astronomy, the Pleiades, or Seven Sisters , is an open star cluster containing middle-aged hot B-type stars located in the constellation of Taurus. It is among the nearest star clusters to Earth and is the cluster most obvious to the naked eye in the night sky...

. The total list published by Messier finally contained 103 objects, but the list "got an independent life" by successive additions by other astronomers, motivating the additions by side notes in Messier’s and Mechain’s texts indicating that either of them knew of the objects. The first such addition came from Nicolas Camille Flammarion in 1921, who added Messier 104 after finding Messier’s side note in his 1781 edition exemplar of the catalogue. M105
Messier 105
Messier 105 is an elliptical galaxy in the constellation Leo. Messier 105 is known to have a supermassive black hole.-History:...

 to M107
Messier 107
Globular Cluster M107 is a very loose globular cluster in the constellation Ophiuchus. It was discovered by Pierre Méchain in April 1782 and independently by William Herschel in 1793...

 were added by Helen Sawyer Hogg
Helen Sawyer Hogg
Helen Battles Sawyer Hogg, CC was a prolific astronomer noted for her research into globular clusters...

 in 1947, M108
Messier 108
Messier 108 is a barred spiral galaxy in the constellation Ursa Major. It was discovered by Pierre Méchain in 1781 or 1782. From the perspective of the Earth, this galaxy is seen almost edge-on....

 and M109
Messier 109
Messier 109 is a barred spiral galaxy approximately away in the constellation Ursa Major. M109 can be seen southeast of the star Phecda .-History:Messier 109 was discovered by Pierre Méchain in 1781...

 by Owen Gingerich
Owen Gingerich
Dr. Owen Jay Gingerich is a former Research Professor of Astronomy and of the History of Science at Harvard University, and a senior astronomer emeritus at the Smithsonian Astrophysical Observatory...

 in 1960, and M110
Messier 110
Messier 110 is a dwarf spheroidal galaxy that is a satellite of the Andromeda Galaxy. M110 contains some dust and hints of recent star formation, which is unusual for dwarf elliptical galaxies in general.-History:...

 by Kenneth Glyn Jones. M102
Messier 102
Messier 102 is a galaxy listed in the Messier Catalogue that has not been identified unambiguously. Its original discoverer Pierre Méchain later said that it was a duplicate observation of Messier 101, but there are historical and observational reasons to believe that it could be NGC 5866,...

 was observed by Méchain, who communicated his notes to Messier; later, it was admitted by Méchain himself that this object does not exist, and it was simply a re-observation of M101. Some sources mention the galaxy NGC 5866
NGC 5866
NGC 5866 is a relatively bright lenticular or spiral galaxy in the constellation Draco. NGC 5866 was probably discovered by Pierre Méchain or Charles Messier in 1781, and independently found by William Herschel in 1788.-Dust disk:One of the most outstanding features of NGC 5866 is the extended...

 as an identification for M102, but its description does not fit with Méchain's notes.

Messier's final catalogue was included in the Connaissance des Temps for 1784 (published in 1781). These objects are still known by their "Messier number" from this list.

Messier lived and did his astronomical work at the Hotel de Cluny, in France in the Earth's northern hemisphere
Northern Hemisphere
The Northern Hemisphere is the half of a planet that is north of its equator—the word hemisphere literally means “half sphere”. It is also that half of the celestial sphere north of the celestial equator...

. For this reason, the list he compiled contains only objects found in the sky area he could observe: from the north celestial pole
Celestial pole
The north and south celestial poles are the two imaginary points in the sky where the Earth's axis of rotation, indefinitely extended, intersects the imaginary rotating sphere of stars called the celestial sphere...

 to a celestial latitude of about −35.7°. Many impressive objects visible only from the southern hemisphere, such as the Large
Large Magellanic Cloud
The Large Magellanic Cloud is a nearby irregular galaxy, and is a satellite of the Milky Way. At a distance of slightly less than 50 kiloparsecs , the LMC is the third closest galaxy to the Milky Way, with the Sagittarius Dwarf Spheroidal and Canis Major Dwarf Galaxy lying closer to the center...

 and Small
Small Magellanic Cloud
The Small Magellanic Cloud is a dwarf galaxy. It has a diameter of about 7,000 light-years and contains several hundred million stars. It has a total mass of approximately 7 billion times the mass of our Sun....

 Magellanic Clouds
Magellanic Clouds
The two Magellanic Clouds are irregular dwarf galaxies visible in the southern hemisphere, which are members of our Local Group and are orbiting our Milky Way galaxy...

, are not listed.

All of the Messier objects are visible with binoculars or small telescopes (under favorable conditions); therefore they are popular viewing objects for amateur astronomers. In early spring astronomers sometimes gather for "Messier marathon
Messier marathon
A Messier marathon is an attempt, usually organized by amateur astronomers, to find as many Messier objects as possible during one night. The Messier catalogue was compiled by French astronomer Charles Messier during the late 18th century and consists of 110 relatively bright deep sky objects...

s", when all of the objects can be viewed over a single night.

A summary of the astrophysics of each Messier object can be found in the Concise Catalog of Deep-sky Objects.

See also


:Category:Messier objects
  • Deep sky object
  • New General Catalogue
    New General Catalogue
    The New General Catalogue of Nebulae and Clusters of Stars is a well-known catalogue of deep sky objects in astronomy. It contains 7,840 objects, known as the NGC objects...

  • Herschel 400 Catalogue
    Herschel 400 Catalogue
    The Herschel 400 catalogue is a subset of William Herschel's original deep sky catalogue of 2,500 deep sky objects, selected by Brenda F. Guzman , Lydel Guzman, Paul Jones, James Morrison, Peggy Taylor and Sara Saey of the Ancient City Astronomy Club in St. Augustine, Florida, USA circa 1980...

  • Caldwell catalogue
    Caldwell catalogue
    The Caldwell Catalogue is an astronomical catalog of 109 bright star clusters, nebulae, and galaxies for observation by amateur astronomers. The list was compiled by Sir Patrick Caldwell-Moore, better known as Patrick Moore, as a complement to the Messier Catalogue.The Messier Catalogue is used...


External links

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