In 1774, Mechain obtained the more permanent post as a calculator with the Depot of the Navy. At that time, he has met Charles Messier, who worked for the same department, but at the small observatory at Hotel de Cluny. Apparently, the two astronomers became friends around this time.
On the new post, Mechain was first involved in surveys of the French coastline. In addition, he had occasion to make some observations at Versailles. In 1774, he observed an occultation of Aldebaran by the Moon, which he later presented as a memoir to the Academy of Sciences.
Like Messier, Pierre Mechain became much devoted to comet observing and hunting. Also like Messier, he soon started to stumble over nebulous objects, and between 1779 and 1782, discovered the considerable number of 30 deep sky objects, 29 of which were original firsts. As apparently he had got in close cooperation with Charles Messier at that time, he almost instantly communicated his observations to Charles Messier, who usually checked their positions and added them to his catalog. Both astronomers undertook a vigorous effort to find more nebulae between late August 1780 and March 1781, when the manuscript for the final version of the Messier catalog was sent out to print. Mechain's last two contributions, M102 and M103, went into the publication unchecked and without positions.
Four additional findings of Mechain missed the publication; these are now known as M104, M105, M106, and M107. He communicated them to Bernoulli, the editor of the Berliner Astronomisches Jahrbuch, in a letter dated May 6, 1783. As these four objects were not contained in the original Messier catalog, they were longly attributed separately to Pierre Mechain (e.g. by John Herschel and J.L.E. Dreyer, the author of the NGC). In this same letter, Mechain disclaimed - possibly in error - his discovery of M102 as an erroneous re-observation of M101, thereby initiating a still open discussion on the identity of this object.
Mechain discovered his first two comets in 1781, and because of his mathematical skills, he was able to calculate their orbits. He was made a member of the Academy of Sciences in 1782. A third comet followed in 1785, and in 1786, he discovered another one which later became famous as "Comet Encke" (after the calculater of its orbit, the German astronomer J.F. Encke). Comet Encke was later independently rediscovered by Caroline Herschel in 1792 and by Pons in 1805, and is the shortest-periodic comet ever discovered, with a period of 3.5 years.
In 1786, Pierre Mechain became an associate editor of the Connaissance des Temps, the journal which had e.g. published the Messier Catalog - one year after Charles Messier had been appointed for the same job.
In 1787, Mechain collaborated with J.D. Cassini and Legendre on measuring the acurate longitude difference between Paris and Greenwich. All three visited William Herschel at his observatory in Slough in the same year.
Mechain discovered his fifth comet in the same year, 1787. His next, 6th discovery occurred in 1790; this finding was periodic comet Tuttle with a period of 13.75 years, as recognized by Tuttle in 1858.
In 1791, a project was initiated of a new survey of the meridian from Dunkirk to Barcelona, and Mechain undertook the southern part, together with an assistant, Tranchot. The operation started June 25, 1792, suffering from various difficulties caused by the French revolution: At one time, Mechain and Tranchot got arrested by revolutioneers in Essone, who first mistook their instruments as weapons, but later let them proceed.
When in Spain, Mechain got hurt in an accident, and when he had recovered, war had broken out between France and Spain, and he got interned. Nevertheless, he discovered another comet, his 7th, from Barcelona on January 10, 1793. During the terror regime in Paris, while Mechain himself was away, all of his property got lost, and his family suffered greatly. Mechain was eventually allowed to leave Spain for Italy, where he stayed at Genoa for some time, and returned to Paris finally in 1795.
On his return, he bacame member of the new Academy of Sciences, and the Bureau of Longitudes. Moreover, he was made director of the Paris Observatory, where he discovered his 8th and last comet on December 26, 1799; Messier took part in observing this one in order to obtain its orbit.
Apparently, Mechain was concerned about the quality of the results of his survey, and refused to publish them for a long time. Eventually, he got permission from Napoleon to extend the survey, and left Paris in 1803.
After completing part of this work, Pierre Mechain caught yellow fever and died in Castillion de la Plana in Spain on September 20, 1804.
M63 1779 Jun 14 M78 1780 Begin M65 1780 Mar 1 M66 1780 Mar 1 M68 1780 Apr 9 [M71] 1780 Jun 28 orig: De Chéseaux 1745-6 [M81] 1780 Aug orig: Bode 1774 Dec 31 [M82] 1780 Aug orig: Bode 1774 Dec 31 M75 1780 Aug 27 M72 1780 Aug 30 M76 1780 Sep 5 M74 1780 Sep End M79 1780 Oct 26 M77 1780 Oct 29 [M80] 1781 Jan 27 orig: Messier 1781 Jan 4 M97 1781 Feb 16 M108 1781 Feb 16 M109 1781 Feb 16 M85 1781 Mar 4 M98 1781 Mar 15 M99 1781 Mar 15 M100 1781 Mar 15 M95 1781 Mar 20 M96 1781 Mar 20 NGC 5195 1781 Mar 20 companion of M51 M94 1781 Mar 22 M105 1781 Mar 24 M101 1781 Mar 27 M102? 1781 Mar End (NGC 5866) disclaimed by Mechain; still controverse M103 1781 Mar End M104 1781 May 11 M106 1781 Jul M107 1782 Apr
Last Modification: 22 Jan 2000, 12:00 MET