Pierre Méchain

Pierre -François- André Méchain ( born August 16, 1744 Laon, France, † September 20, 1804 in Castellon de la Plana, Spain) was a French astronomer and geographer.

Life

He discovered eight comets and 26 objects outside our solar system and took part in an expedition, the result of which was used as a definition of the meter.

Pierre Méchain, was born in the north of France, the son of the architect Pierre -François Méchain and Marie -Marguerite Roze. He originally wanted to become an architect and studied mathematics and physics. However, due to financial difficulties he had to leave the university. At times, he worked as a tutor of two boys, about 50 km from Paris. He became friends with Jérôme de Lalande, who gave him advance features of his work " L' Astronomy ". 1772 Lalande got him a job as a hydraulic Count on the card instead of the Navy in Versailles. The site was initially limited in time and Méchain bolstered his income by teaching mathematics.

1774 Méchain got a permanent position as a computer in the Navy and was initially concerned with the accurate determination of the French coastline. In this time he met Charles Messier know, who was also employed by the Navy, but worked in a small observatory at the Hôtel de Cluny.

In 1777 he married Barbe- Thérèse Marjou. They had two sons, Jerome and Augustine, and a daughter.

In addition to his work at Versailles Méchain led by astronomical observations. In 1774 he held an occultation of the star Aldebaran by the moon. Like his friend Messier, he became the " comet hunter ". The position of unknown misty objects for which it could be either comets, he stated further Messier who reviewed this and enlisted in his catalog. In this way Méchain discovered 26 deep-sky objects, including the globular cluster M80 and the M102 and M103 galaxies.

His first comet discovered Méchain, 1781. Due to his mathematical knowledge, he was able to determine its orbit. He studied the records of the comets of 1532 and 1661 and refuted the then prevalent theory that it was one and the same object. In 1782 he received the Prize of the Academy of Sciences and became its member. In 1786 he discovered a comet which now bears the name of Encke. Encke was rediscovered independently in 1792 by Caroline Herschel in 1805 by Jean -Louis Pons. The astronomer Johann Franz Encke could finally determine its course, and it was found that Encke is with an orbital period of only 3.5 years, the comet with the shortest period. 1790 Méchain discovered a periodic comet which now bears the name 8P/Tuttle.

After 1780 Méchain made ​​several trips, inter alia, to Germany and northern Italy to make to cards. In 1785 he became editor of the magazine " Connaissance des Temps ", which had at that time published the Messier catalog.

1787 Méchain collaborated with Jean Dominique Comte de Cassini and Adrien -Marie Legendre to determine the exact difference of longitude between Paris and Greenwich. In the same year three the German -born astronomer William Herschel visited in his observatory in Slough.

1792, the distance between Dunkirk and Barcelona should be determined exactly. At the so-called Meridian expedition, Jean -Baptiste Joseph Delambre attended. Méchain and his assistant Jean Joseph Tranchot took over while the southern sector. The expedition turned out to be due to the aftermath of the French Revolution as difficult. Méchain Tranchot and were even briefly detained in Essonne of revolutionaries who held their scientific instruments for weapons. In Spain Méchain was injured in an accident. When he finally recovered, broke from the French - Spanish war, and he was interned. During this time he discovered from Barcelona on January 10, 1793 his seventh comet. Here he also believed a mistake in his calculations of the width to have discovered of Barcelona, ​​with impacts on the Meridian Project. The error does not let go of him, led him to self-doubt and depression, which delayed his work later, and were also a reason why he later returned to Spain. In 1794 he was able to travel to Genoa, where he remained for a year before he returned to Paris in 1795. During his stay abroad Méchain lost his entire property in France, and his family was subjected to severe reprisals. On his return in 1795 him great honors were bestowed. He became a member of the new Academy of Sciences, the Bureau des Longitudes and director of the Paris Observatory. Here he discovered on December 26, 1799 his last comet.

Méchain was known for the accuracy of his work, his work has been laid for a long time. Napoleon Bonaparte gave him the permission to extend his investigations, and Méchain left Paris in 1803. In Spain, he fell ill and died in 1804 of yellow fever.

In his memory, the asteroid ( 21785 ) Méchain was named.