Pierre Méchain
Encyclopedia
Pierre François André Méchain (16 August 1744 – 20 September 1804) was a French
astronomer
and surveyor
who, with Charles Messier
, was a major contributor to the early study of deep sky objects and comets.
, the son of the ceiling designer and plasterer Pierre François Méchain. He displayed mental gifts in mathematics
and physics
but had to give up his studies for lack of money. However, his talents in astronomy
were noticed by Joseph Jérôme Lalande, for whom he became a friend and proof-reader. Lalande then secured a position for him with the Naval Depot of Maps at Versailles
, where he worked through the 1770s engaged in hydrographic
work and coastline surveying. It was during this time—approximately 1774—that he met Charles Messier, with whom he also became friends. In this year he also produced his first astronomical work, a paper on an occultation of Aldebaran
by the Moon
.
In 1777 he married Barbe-Thérèse Marjou, who bore him two sons and a daughter. He was admitted to the French Académie des sciences in 1782, and was the editor of Connaissance des Temps
from 1785 to 1792; this was the journal which, among other things, first published the list of Messier objects.
With his surveying skills, he worked on maps of Northern Italy
and Germany
after this, but his most important mapping work was geodetic
: the determination of the southern part of the meridian arc
of the Earth
's surface between Dunkirk and Barcelona
beginning in 1791. This measurement would become the basis of the metric system
's unit of length, the meter. He encountered numerous difficulties on this project, largely stemming from the effects of the French Revolution
. He was arrested after it was suspected his instruments were weapons, he was interned in Barcelona after war broke out between France and Spain, and his property in Paris
was confiscated during The Terror. He was released from Spain to live in Italy
, then returned home in 1795.
From 1799, he was the director of the Paris Observatory
.
Continuing doubts about his measurements of the Dunkirk-Barcelona arc led him to return to that work. This took him back to Spain
in 1804, where he caught yellow fever
and died in Castellon de la Plana
.
He independently discovered four others, originally discovered by someone else but unknown to him at the time and included in the Messier catalog: M71
, discovered by Philippe de Cheseaux in the 1740s; M80
, discovered by Messier about two weeks earlier than Méchain's observation; and M81
and M82
, discovered originally by Johann Bode.
Six other discoveries are "honorary Messier objects" added to the list in the 20th century: M104
, M105
, M106
, M107
, M108
, M109.
He also discovered NGC 5195
, the companion galaxy that makes M51 (AKA the Whirlpool Galaxy
) so distinctive.
One other Messier object can be attributed to him, M102. However, Méchain specifically disavowed the observation from 1783 onwards as a mistaken re-observation of M101. Since that time, others have proposed that he did in fact observe another object, and suggested what they might be. See the discussion The M102 Controversy for more details.
Interestingly, Méchain never set out to observe deep-sky objects. Like Messier, he was solely interested in cataloging objects that might be mistaken for comets; having done so, he was the second-most successful discoverer of comets of his time, after Messier himself.
Altogether, he discovered nine comets either alone or in combination with Messier . His sole discoveries are:
His co-discovery with Messier was C/1785 A1 (Messier-Mechain), former designation 1785 I. Note that only the two named comets have been connected to periodic comets that have computed orbits and in neither case was he an observer when they were computed, so by that technical definition (commonly used for comets since the 19th century) Méchain did not discover any of these nine.
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
Astronomer
An astronomer is a scientist who studies celestial bodies such as planets, stars and galaxies.Historically, astronomy was more concerned with the classification and description of phenomena in the sky, while astrophysics attempted to explain these phenomena and the differences between them using...
and surveyor
Surveying
See Also: Public Land Survey SystemSurveying or land surveying is the technique, profession, and science of accurately determining the terrestrial or three-dimensional position of points and the distances and angles between them...
who, with 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"...
, was a major contributor to the early study of deep sky objects and comets.
Life
Pierre Méchain was born in LaonLaon
Laon is the capital city of the Aisne department in Picardy in northern France.-History:The hilly district of Laon, which rises a hundred metres above the otherwise flat Picardy plain, has always held strategic importance...
, the son of the ceiling designer and plasterer Pierre François Méchain. He displayed mental gifts in mathematics
Mathematics
Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...
and physics
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
but had to give up his studies for lack of money. However, his talents in astronomy
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...
were noticed by Joseph Jérôme Lalande, for whom he became a friend and proof-reader. Lalande then secured a position for him with the Naval Depot of Maps at Versailles
Versailles
Versailles , a city renowned for its château, the Palace of Versailles, was the de facto capital of the kingdom of France for over a century, from 1682 to 1789. It is now a wealthy suburb of Paris and remains an important administrative and judicial centre...
, where he worked through the 1770s engaged in hydrographic
Hydrography
Hydrography is the measurement of the depths, the tides and currents of a body of water and establishment of the sea, river or lake bed topography and morphology. Normally and historically for the purpose of charting a body of water for the safe navigation of shipping...
work and coastline surveying. It was during this time—approximately 1774—that he met Charles Messier, with whom he also became friends. In this year he also produced his first astronomical work, a paper on an occultation of Aldebaran
Aldebaran
Aldebaran is a red giant star located about 65 light years away in the zodiac constellation of Taurus. With an average apparent magnitude of 0.87 it is the brightest star in the constellation and is one of the brightest stars in the nighttime sky...
by the Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...
.
In 1777 he married Barbe-Thérèse Marjou, who bore him two sons and a daughter. He was admitted to the French Académie des sciences in 1782, and was the editor of Connaissance des Temps
Connaissance des Temps
The Connaissance des temps is an official astronomical yearly publication in France.- History :Connaissance des temps is the oldest such publication in the world, published without interruption since 1679 , after the astronomer Jean Picard obtained from the King the right to create the journal...
from 1785 to 1792; this was the journal which, among other things, first published the list of Messier objects.
With his surveying skills, he worked on maps of Northern Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
and Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
after this, but his most important mapping work was geodetic
Geodesy
Geodesy , also named geodetics, a branch of earth sciences, is the scientific discipline that deals with the measurement and representation of the Earth, including its gravitational field, in a three-dimensional time-varying space. Geodesists also study geodynamical phenomena such as crustal...
: the determination of the southern part of the meridian arc
Meridian arc
In geodesy, a meridian arc measurement is a highly accurate determination of the distance between two points with the same longitude. Two or more such determinations at different locations then specify the shape of the reference ellipsoid which best approximates the shape of the geoid. This...
of the Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
's surface between Dunkirk and Barcelona
Barcelona
Barcelona is the second largest city in Spain after Madrid, and the capital of Catalonia, with a population of 1,621,537 within its administrative limits on a land area of...
beginning in 1791. This measurement would become the basis of the metric system
Metric system
The metric system is an international decimalised system of measurement. France was first to adopt a metric system, in 1799, and a metric system is now the official system of measurement, used in almost every country in the world...
's unit of length, the meter. He encountered numerous difficulties on this project, largely stemming from the effects of the French Revolution
French Revolution
The French Revolution , sometimes distinguished as the 'Great French Revolution' , was a period of radical social and political upheaval in France and Europe. The absolute monarchy that had ruled France for centuries collapsed in three years...
. He was arrested after it was suspected his instruments were weapons, he was interned in Barcelona after war broke out between France and Spain, and his property in Paris
Paris
Paris is the capital and largest city in France, situated on the river Seine, in northern France, at the heart of the Île-de-France region...
was confiscated during The Terror. He was released from Spain to live in Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
, then returned home in 1795.
From 1799, he was the director of the Paris Observatory
Paris Observatory
The Paris Observatory is the foremost astronomical observatory of France, and one of the largest astronomical centres in the world...
.
Continuing doubts about his measurements of the Dunkirk-Barcelona arc led him to return to that work. This took him back to Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
in 1804, where he caught yellow fever
Yellow fever
Yellow fever is an acute viral hemorrhagic disease. The virus is a 40 to 50 nm enveloped RNA virus with positive sense of the Flaviviridae family....
and died in Castellon de la Plana
Castellón de la Plana
Castellón de la Plana or Castelló de la Plana is the capital city of the province of Castelló, in the Valencian Community, Spain, in the east of the Iberian Peninsula, on the Costa del Azahar by the Mediterranean Sea...
.
Discoveries
Méchain discovered either 26 or 27 deep-sky objects, depending on how one counts M102. Eighteen of these were included in the Messier catalog:- Sunflower Galaxy, the Sunflower Galaxy
- Globular Cluster M72Messier 72Messier 72 is a globular cluster in the Aquarius constellation discovered by Pierre Méchain on August 29, 1780. Charles Messier looked for it on the following October 4 and 5, and included it in his catalog...
- Spiral Galaxy M74Messier 74Messier 74 is a face-on spiral galaxy in the constellation Pisces. It is at a distance of about 32 million light-years away from Earth. The galaxy contains two clearly defined spiral arms and is therefore used as an archetypal example of a Grand Design Spiral Galaxy...
, the Phantom Galaxy - Globular Cluster M75Messier 75Messier 75 is a globular cluster in the constellation Sagittarius. It was discovered by Pierre Méchain in 1780 and included in Charles Messier's catalog of comet-like objects that same year....
- Little Dumbbell Nebula, the Little Dumbbell Nebula
- Spiral Galaxy M77Messier 77Messier 77 is a barred spiral galaxy about 47 million light-years away in the constellation Cetus. Messier 77 is an active galaxy with an Active Galactic Nucleus , which is obscured from view by astronomical dust at visible wavelengths...
- M78Messier 78The nebula Messier 78 is a reflection nebula in the constellation Orion. It was discovered by Pierre Méchain in 1780 and included by Charles Messier in his catalog of comet-like objects that same year....
- Globular Cluster M79Messier 79Messier 79 is a globular cluster in the Lepus constellation. It was discovered by Pierre Méchain in 1780...
- Messier 85Messier 85Messier 85 is a lenticular galaxy in the Coma Berenices constellation. It is 60 million light years away, making it the 94th most distant Messier object, and it estimated to be 125,000 light years across....
- M94Messier 94Messier 94 is a spiral galaxy in the constellation Canes Venatici. It was discovered by Pierre Méchain in 1781,...
- M95Messier 95Messier 95 is a barred spiral galaxy about 38 million light-years away in the constellation Leo. It was discovered by Pierre Méchain in 1781, and catalogued by Charles Messier four days later.-Nucleus:...
- M96Messier 96Messier 96 is an intermediate spiral galaxy about 31 million light-years away in the constellation Leo. It was discovered by Pierre Méchain in 1781.-M96 Group:...
- Owl Nebula, the Owl Nebula
- M98Messier 98Messier 98 is an intermediate spiral galaxy about 60 million light-years away in the constellation Coma Berenices. It was discovered by Pierre Méchain on March 15, 1781 along with M99 and M100 and was cataloged as a Messier object on April 13, 1781...
- M99Messier 99Messier 99 is an unbarred spiral galaxy approximately 50 million light-years away in the constellation Coma Berenices....
, the Coma Pinwheel Galaxy - M100Messier 100Messier 100 is an example of a grand design spiral galaxy located within the southern part of constellation Coma Berenices. It is one of the brightest galaxies in the Virgo cluster, approximately 55 million light-years distant from Earth and has a diameter of 160,000 light years...
- Pinwheel Galaxy, the Pinwheel Galaxy
- M102Messier 102Messier 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,...
, an object listed in the Messier Catalogue that remains unidentified - M103Messier 103Messier 103 is an open cluster where a few thousand stars formed in the constellation Cassiopeia. This open cluster was discovered in 1781 by Charles Messier’s friend and collaborator Pierre Méchain. It is one of the most distant open clusters, with distances of 8,000 to 9,500 light years from the...
He independently discovered four others, originally discovered by someone else but unknown to him at the time and included in the Messier catalog: M71
Messier 71
Messier 71 is a globular cluster in the constellation Sagitta. It was discovered by Philippe Loys de Chéseaux in 1746 and included by Charles Messier in his catalog of comet-like objects in 1780...
, discovered by Philippe de Cheseaux in the 1740s; M80
Messier 80
Messier 80 is a globular cluster in the constellation Scorpius. It was discovered by Charles Messier in 1781....
, discovered by Messier about two weeks earlier than Méchain's observation; and M81
Messier 81
Messier 81 is a spiral galaxy about 12 million light-years away in the constellation Ursa Major. Due to its proximity to Earth, large size and active galactic nucleus Messier 81 (also known as NGC 3031 or Bode's Galaxy) is a spiral galaxy about 12 million light-years away in the constellation Ursa...
and M82
Messier 82
Messier 82 is the prototype nearby starburst galaxy about 12 million light-years away in the constellation Ursa Major...
, discovered originally by Johann Bode.
Six other discoveries are "honorary Messier objects" added to the list in the 20th century: M104
Sombrero Galaxy
The Sombrero Galaxy is an unbarred spiral galaxy in the constellation Virgo located 28 million light years from earth. It has a bright nucleus, an unusually large central bulge, and a prominent dust lane in its inclined disk. The dark dust lane and the bulge give this galaxy the appearance of a...
, M105
Messier 105
Messier 105 is an elliptical galaxy in the constellation Leo. Messier 105 is known to have a supermassive black hole.-History:...
, M106
Messier 106
Messier 106 is a spiral galaxy in the constellation Canes Venatici. It was discovered by Pierre Méchain in 1781. M106 is at a distance of about 22 to 25 million light-years away from Earth...
, 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...
, 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....
, M109.
He also discovered NGC 5195
NGC 5195
NGC 5195 is a dwarf galaxy that is interacting with the Whirlpool Galaxy . Both galaxies are located approximately 25 million light-years away in the constellation Canes Venatici...
, the companion galaxy that makes M51 (AKA the Whirlpool Galaxy
Whirlpool Galaxy
The Whirlpool Galaxy is an interacting grand-design spiral galaxy that is estimated to be 23 ± 4 million light-years from the Milky Way Galaxy. in the constellation Canes Venatici...
) so distinctive.
One other Messier object can be attributed to him, M102. However, Méchain specifically disavowed the observation from 1783 onwards as a mistaken re-observation of M101. Since that time, others have proposed that he did in fact observe another object, and suggested what they might be. See the discussion The M102 Controversy for more details.
Interestingly, Méchain never set out to observe deep-sky objects. Like Messier, he was solely interested in cataloging objects that might be mistaken for comets; having done so, he was the second-most successful discoverer of comets of his time, after Messier himself.
Altogether, he discovered nine comets either alone or in combination with Messier . His sole discoveries are:
- C/1781 M1 (Mechain), 1781 I
- C/1781 T1 (Mechain), 1781 II
- C/1785 E1 (Mechain), 1785 II
- 2P/Encke, discovered in 1786
- C/1787 G1 (Mechain), 1787 I
- 8P/Tuttle8P/Tuttle8P/Tuttle is a periodic comet in our solar system. Perihelion was late January 2008, and as of February was visible telescopically to Southern Hemisphere observers in the constellation Eridanus. On December 30, 2007 it was in close conjunction with spiral galaxy M33...
, discovered in 1790 - C/1799 P1 (Mechain), 1799 II
- C/1799 Y1 (Mechain), 1799 III
His co-discovery with Messier was C/1785 A1 (Messier-Mechain), former designation 1785 I. Note that only the two named comets have been connected to periodic comets that have computed orbits and in neither case was he an observer when they were computed, so by that technical definition (commonly used for comets since the 19th century) Méchain did not discover any of these nine.