Observatory of Paris

The observatory of Paris was born from the project, in 1667, to create a astronomical Observatoire equipped with good instruments making it possible to establish charts for navigation. It comes in complement from the founded Academy of Science in 1666.

He played a very important part in the Astronomie Occident ale. It is there that occurred of the Science S like the Géodésie, the Cartographie and the Météorologie.

The observatory of Paris is currently established on three sites: Paris, Meudon and Nançay.

History

Under the pressure of many scientists and in particular Adrien Auzout which writes, in 1665, a letter with Louis XIV to ask him to create without awaiting more a company of sciences and arts .

It is in 1666 that Louis XIV and Jean-Baptiste Colbert found the royal Académie of sciences. At its first meeting, the December 22nd 1666, it is decided the creation of the royal observatory, which will become later the current observatory of Paris. It was to be used of meeting room and experimentation for all the academicians. But because of its distance of Paris of the time, only the astronomers use it.

The June 21st 1667 (day of the Summer solstice), the mathematicians of the Academy trace on the ground, with the current site of the building, the meridian line and the other directions necessary to the exact establishment of the building designed by the Architecte and doctor Claude Perrault (whose brother Charles was secretary of Colbert). The median plane of the Observatory will define from now on the Méridien of Paris. As of 1669, Colbert calls Jean-Dominique Cassini to direct the Observatory, it makes carry out modifications of the building.

The site of Meudon was established with the site of old the Château of Meudon.

Dynasty of Cassini

It was directed during the first 125 years by the Cassini family:
  • Jean-Dominique Cassini (Cassini I), of 1669 with 1712 gives him a fast expansion. During this period, large astronomers like Huygens, Roëmer and others attend the Observatory. Jean Picard takes a measurement of the terrestrial degree there thus melting geodesy.
  • Jacques Cassini (Cassini II), his son, takes the changing of 1712 with 1756. The Observatory is then directed by the Academy of Science. But in the facts, the director has a very great independence.
  • César-François Cassini (Cassini III also called Cassini de Thury), the small son, directs it 1756 to 1784. It is during this period that studies in geodesy and cartography develop.
  • Jean-Dominique, count de Cassini (Cassini IV), the back small son, undergoes the attacks of the French revolution and directs the Observatory starting from 1784. Being monarchist, he resigns in 1793.
All Cassini were very present within the Observatory, and lived even on the spot.

After the Revolution

After the resignation of the count de Cassini, the observatory is somewhat abused by the French revolution because of its very strong bonds with monarchy. A rather muscular inspection takes place even to find weapons and vivres, but nothing like it will not be found in the buildings Observatory. The money is also lacking.

In 1795, a decree attaches the observatory to the Bureau of longitudes, whose mission is to develop astronomy. The astronomers Lalande, Jean-Dominique Cassini, Pierre-François-Andre Méchain and Jean-Baptiste Joseph Delambre are statutory and perceive wages.

During the following years, the position of director will be allotted successively to:

However, it should be noted that during this period, the direction of the observatory goes hand in hand with the presidency (renewed annually) of the Office of longitudes, and concerns only the administrative office and nonscientific, because the astronomers are autonomous with regard to the course chosen for their work. Alexis Bouvard was thus, as a treasurer of the Office of longitudes, in load of the administration of the Observatory of 1808 until its death in 1843. In April 1834, following the adoption of a new payment of the Office of longitudes concerning the service of the Observatory of Paris, François Arago is named director of the observations, charged with supervising the regular work of the establishment, entrusted to pupils astronomers.

François Arago develops at the observatory the Polymétrie and the photometry and carries out the first Daguerréotype there Sun. During this period, Foucault introduces the Miroir reflectors with money deposit.

Urbain the Glassmaker occupies the position of director of 1854 with 1870. It founds there meteorology, the office of meteorology is then moved with the Parc Montsouris. Being very close to the new capacity and also member of the Senate, it manages to extend the capacities of the director of the Observatory. It also manages to increase the pays of the astronomers. But its authoritative character creates important tensions with the personnel of the observatory. Shortly after the collective resignation of 14 astronomers, it is raised of its station.

Jules Jansen presents a project of restoration of the castle of Meudon, obtains the required funds (more than one franc million of the time) and there founds the Physical Observatory of Astronomy in 1876. A large cupola is created which always shelters instruments of observation. The Observatory of Meudon remains one of the reference laboratories for the study of the Sun.

The Admiral Mouchez of 1878 with 1892, until its death, directs in its turn the Observatory. It decides, in 1887, the creation of the Sky chart , project in which take part 180 observatories throughout the world. It renovates the apparatuses, opens the observatory with the public and unifies the hour in France, per hour of the meridian line of Paris.

François-Felix Tisserand takes the direction of the Observatory of 1892 with 1896, until its death. While working out its Treated of celestial mechanics , it follows very close the various works in progress and day before to the good performance of the material.

It is then with the turn of Maurice Lœwy to ensure the direction of the Observatory, of 1897 with 1907, until its death. It takes an active part in the development of the Sky chart .

Benjamin Baillaud takes the position of director of 1908 with 1926. He is the initiator of the creation of the International office of the hour. He takes an active part in the restoration of the French astronomical equipment.

Of 1927 with 1929, it is Henri Deslandres which ensures the direction of the observatory. Deslandres was the director of the Observatoire of Meudon. The fastening of this observatory with that of Paris gives access to him the position of director. Deslandres wanted to transfer all the astronomical equipment from Paris towards Meudon, by keeping in the capital only the administrative one. This project will never be applied.

Ernest Esclangon ensures the direction of 1927 1944. It will be in particular at the origin of the creation of the speaking Horloge in 1932. To ensure the continuity of the time Service , whereas France are invaded by the Germany, Esclangon and part of the personnel leave to Bordeaux. It is Armand Lambert which ensures the direction by interim of the observatory. After the Armistice, the observatory preserves an about normal activity. Being Jewish, Lambert continues in spite of very ensuring its work. It is stopped in 1943 and is sent to Auschwitz, from where it will not return.

At the end of the Second world war, the position of director is allotted to André Danjon, which will exert it until in 1963. Before having the position of director, Danjon enjoys already a very strong reputation. It is thanks to this one that it extends the means of the Observatory enormously, in particular as a personnel. He also takes an active part in making of equipment like the electronic Caméra. Because of the increase in the number of scientists within the Observatory, it will make build several other buildings and will limit the height and the lighting of the buildings present around the Observatory, so as to keep a certain quality of sight. In 1953, the Observatoire of Nançay is attached to the Observatory of Paris. This fastening makes it possible to make many discoveries on the solar Couronne and Jupiter.

Contemporary time

Established on the three sites of Paris, Meudon and Nançay, the Observatory of Paris is a Grand concerning establishment Ministère of Higher education and Research. It is the largest national pole of research in astronomy. It is currently chaired by Daniel Egret.

The research led to the Observatory of Paris covers all the fields of astronomy and contemporary astrophysics, while studying:

The researchers and engineers of the Observatory produce instruments of observation for the Télescope S on the ground or the space probes, organize observation campaigns, set up the treatment and the data analysis of observation, work out databases, or carry out digital simulations making it possible to model the astrophysical phenomena and to make theoretical interpretation of it.

The Observatory of Paris shelters a doctoral school and activities of training of the Masters and develops a numerical campus: Astrophysical to measure.

List former directors

Bibliographical resource

See too

Related articles

External bonds

  • Official site
  • Photographs of the Observatory of Meudon

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