Paris Observatory

Paris Observatory

The Paris Observatory (French: Observatoire de Paris or Observatoire de Paris-Meudon) is the foremost astronomical observatory of France, and one of the largest astronomical centers in the world. Its historic building is to be found on the Left Bank of the Seine in central Paris, but most of the staff works on a satellite campus in the Meudon suburb of Paris.

Constitution

Meridian Room (or Cassini Room) at the Paris Observatory. The Paris Meridian is traced on the floor.

Administratively, it is a grand établissement of the French Ministry of National Education, with a status close to that of a public university. Its missions include:

• research in astronomy and astrophysics;
• education (four graduate programs, Ph.D. studies);
• diffusion of knowledge to the public.

It maintains a solar observatory at Meudon () and a radio astronomy observatory at Nançay. It was also the home to the International Time Bureau until its dissolution in 1987.

History

The observatory in the beginning of the eighteenth century with the wooden "Marly Tower" on the right, moved to the grounds by Giovanni Cassini, for the mounting of long tubed telescopes and even longer tubeless aerial telescopes.

Its foundation lies in the ambitions of Jean-Baptiste Colbert to extend France's maritime power and international trade in the 17th century. Louis XIV promoted its construction starting in 1667, being completed in 1671. It thus predates by a few years the Royal Greenwich Observatory in England, which was founded in 1675. The architect of the Paris Observatory was Claude Perrault whose brother, Charles, was secretary to Colbert and superintendent of public works. Optical instruments were supplied by Giuseppe Campani. The buildings were extended in 1730, 1810, 1834, 1850, and 1951. The last extension incorporates the spectacular Meridian Room designed by Jean Prouvé.

The world's first national almanac, the Connaissance des temps was published by the observatory in 1679, using eclipses in Jupiter's satellites to aid sea-farers in establishing longitude. In 1863, the observatory published the first modern weather maps. In 1882, a 33 cm (13 in) astrographic lens was constructed, an instrument that catalysed what proved to be the over-ambitious, international Carte du Ciel project.

In November 1913, the Paris Observatory, using the Eiffel Tower as an antenna, exchanged sustained wireless (radio) signals with the United States Naval Observatory to determine the exact difference of longitude between the two institutions.

Meudon 83-cm Great Refractor

See also: List of largest optical refracting telescopes and Paris Inch

The Meudon great refractor (Meudon 83-cm) was a 83 cm (33 in) aperture refractor, which with September 20, 1909 observations by E.M. Antoniadi helped disprove the Mars canals theory. It was a double telescope completed in 1891, with secondary having 62 cm (24 in) aperture lens for photography. It was one of the largest active telescopes in Europe.

Directors

The title of director of the Observatory was officially given for the first time to César-François Cassini de Thury by a Royal brevet dated November 12, 1771. However, the important role played by his grandfather and father in this institution during its first century actually gives them somewhat the role of director.

• Giovanni Cassini (1671–1712)
• Jacques Cassini (1712–1756)
• César-François Cassini de Thury (1756–1784)
• Dominique, comte de Cassini (1784–1793)
• Joseph Jérôme Lefrançais de Lalande (1795–1800)
• Pierre Méchain (1800–1804)
• Jean Baptiste Joseph Delambre (1804–1822)
• Alexis Bouvard (1822–1843)
• François Arago (1843–1853)
• Urbain Le Verrier (1854–1870)
• Charles-Eugène Delaunay (1870–1873)
• Urbain Le Verrier (1873–1877)
• Amédée Mouchez (1878–1892)

• Félix Tisserand (1892–1896)
• Maurice Loewy (1896–1907)
• Benjamin Baillaud (1908–1926)
• Henri-Alexandre Deslandres (1926–1929)
• Ernest Esclangon (1929–1944)
• André Danjon (1945–1963)
• Jean-François Denisse (1963–1967)
• Jean Delhaye (1967–1971)
• Raymond Michard (1971–1976)
• Jacques Boulon (1976–1981)
• Pierre Charvin (1981–1991)
• Michel Combes (1991–1999)
• Pierre Couturier (1999–2003)
• Daniel Egret (2003-2011)
• Claude Catala (2011–)

Facilities

Meudon

Solar Observatory Tower

• Solar Observatory Tower Meudon
• Chateau de Meudon
• LESIA space and astrophysics instrumentation research laboratory

Nançay

Nançay radio telescope

Saint-Véran

Also known as the Observatoire du Pic de Château Renard, the Observatoire de Saint-Véran was built in 1974 on top of the Pic de Château Renard (2,900 m or 9,500 ft), on the commune of Saint-Véran in the Haut Queyras (Hautes Alpes département). A coronograph was in operation there for ten years; the dome was moved there from the Perrault building of the Observatoire de Paris.

Nowadays, the AstroQueyras amateur astronomy association operates the facility, using a 60 cm (24 in) telescope on loan from the Observatoire de Haute Provence. Numerous asteroids have been discovered there.

Bibliography

• [Anon.] (2001) "Paris Observatory", Encyclopaedia Britannica, Deluxe CDROM edition
• [1]

External links

• Paris Observatory (official site, in English)
• Paris Observatory History (official site, in English)
• Location in Paris
• Publications of the Observatoire de Paris in Gallica, the digital library of the BnF (in French)