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49-574: Institutionally it was part of the Meudon Observatory, which later became integrated with the Paris observatory . The Great Refractor was used for research well into the 1980s, after nearly a century of use. In the 21st century it was renovated and re-opened for public outreach. The telescope is noted for being used to disprove the theory of Martian canals , which was a popular story in the late 19th century. The telescope lenses were made by

98-472: A 9 cm aperture Dollond telescope, and a telescope by Lerebours. One of the special telescopes in the collection of the observatory, was the Passy telescope of King Louis XV . This telescope was built by Dom Noel in the late 18th century, and was a reflecting telescope with a 61 cm aperture bronze mirror. In 1805 the mirror was re-polished, but it was tarnished again within two years; it remained at

147-486: A Henry astrograph with 13-inch objective was acquired. For the 1907 Transit of Mercury , some of the telescopes used at the Paris Observatory included: The telescopes were mobile and were placed on the terrace for the observations. The Meudon great refractor (Meudon 83-cm) is an 83 cm (33 in) aperture refractor, which, with September 20, 1909 observations by E. M. Antoniadi , helped disprove

196-492: A new one started, with the foundations of the telescopes built on the ruins, and old stables converted into laboratories. The dome building took about ten years of construction from 1880 to 1890. The site has a long history going back to a summer palace designed by Le Primatic, then a summer Palace of the Grand Dauphin by the end of the 17th century; some expansion were done by Jules Hardouin-Mansart. The old château Vieux

245-599: A new site and facilities. It was built in 1891. In addition to these sites, the Marseilles Observatory became a branch of the Paris Observatory in 1863. In 1873, Marseilles Observatory detached from Paris Observatory. King Louis XIV purchased the land for his new observatory in March 1667. This provided a site for the activities of the Academy of Sciences near to the city of Paris. The original buildings

294-534: 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. It remains the source of legal time in France, using multiple atomic fountain clocks maintained by its SYRTE ( Sytèmes de Référence Temps Espace ) department. The Paris Observatory Library, which was founded in 1785, provides

343-414: Is designed to focus blue light, which is the color desired for the film emulsion . (It would be another century before CCD imaging came into force). The lenses in the telescope are a type of glass lens that has two parts, usually called an achromat . The two parts, called a 'crown' and 'flint' have not only a certain shape (i.e. figure) but also a different chemical composition. The crown glass typically

392-524: Is made of steel. The observatory resides in a special park designed by fr:Urbain Vitry , the Parc de l'Observatoire . The dome was originally turned by a 12-horsepower gasoline engine, and electrical power was provided to the dome by an 8 hp engine running a generator. The telescope was noted for an instrument that detected polarization of light , installed in the 1920s by Bernard Lyot . The telescope

441-553: Is made with potassium and sodium silicates, while the flint is usually made with potassium and lead silicates. The 62 cm aperture photographic lens corrected for the colour blue, was not installed until 1898. The 1886 prices for each lens, was 130 thousand francs for the visual, and 50 thousand francs for the photographic. The dome is made of iron and weighs 100 tons. It was made by the firm Etablissements Cali. The Meudon refractor resides in Grande Cupola surrounded by

490-488: The Arago equatorial telescope , was completed. This telescope was proposed by director François Arago in 1846. It was installed in the east tower and was made by Lerebours. This instrument is known to have conducted photometry measurements of Jupiter's moons (there were only four known at that time) in the late 1880s. In 1863 a large transit circle was installed, and in 1878 a meridian instrument. The transit circle of 1863

539-509: The Mars canals theory. It is a double telescope completed in 1891, with a secondary 62 cm (24 in) aperture lens for photography. It was of the largest refracting telescopes in Europe and was active for a century until 1991. In the 21st century, it was renovated and supports public education and visitation. The Meudon refractor was built at Meudon Observatory . It is one of three sites of

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588-658: The Seine in central Paris , but most of the staff work on a satellite campus in Meudon , a suburb southwest of Paris. The Paris Observatory was founded in 1667. .Construction was completed by the early 1670s and coincided with a major push for increased science, and the founding of the Royal Academy of Sciences . King Louis XIV's minister of finance organized a "scientific powerhouse" to increase understanding of astronomy, maritime navigation, and science in general. Through

637-486: The coronagraph , which he invented to observe the corona without having to wait for a solar eclipse. Most of this work implied painstaking long observations at the Pic du Midi Observatory. It was an exceptionally good site, free of both air pollution and light pollution but it came with a disadvantage: In the interwar period access to the peak implied mountaineering skills and physical fitness, especially in winter when access

686-588: The École Polytechnique and studied engineering , physics , and chemistry at the University of Paris . From 1920 until his death he worked for the Meudon Observatory , where in 1930 he earned the title of Joint Astronomer of the Observatory . After gaining the title, he earned a reputation of being an expert of polarized and monochromatic light. Throughout the 1930s, he labored to perfect

735-618: The Academy of Sciences traced the future building's outline on a plot outside town near the Port Royal abbey , with the Paris meridian exactly bisecting the site north–south. The meridian line was used as a basis for navigation and would be used by French cartographers as their prime meridian for more than 200 years. The Paris Observatory predates by a few years the Royal Greenwich Observatory in England, which

784-744: 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. Early telescopes were supplied by

833-475: The Henry Brothers, and the mounting was made by Gautier. Meudon Observatory was founded in 1876, but became part of the Paris Observatory in the 1926. In this period the observatories were not just a telescope, but more like a laboratory, with integrated equipment, libraries, and workshops for practical and theoretical astronomy. A major focus was developing new kinds of instruments. The chief developer

882-696: The Meridian Room designed by Jean Prouvé . In 1671 Saturn's moon Iapetus was discovered from the observatory, followed by Rhea in 1672. The moons Dione and Tethys were also discovered from the observatory in 1684. In 1676 the staff concluded that light itself was travelling at a finite speed. 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,

931-620: The Meudon refractor was noted for being very steady, and this aided in taking micrometer measurements of the Galilean moons of Jupiter. In addition, the surfaces of these bodies were sketched and attempts made to determine their rotation period. In 1954, a ruined ring plain inside the Lunar crater Godin was discovered with the Meudon 83 cm refractor visually. It is noted as a difficult visual observation target from Earth, and it lies west of

980-607: The Moon and Mars. By 1896 the astronomer Henri Perrotin used the great refractor to make observations of planet Jupiter. Starting in 1909 Eugène Antoniadi was able to help disprove the theory of Martian canali by viewing through the great refractor. A trifecta of observational factors synergize; viewing through the third largest refractor in the World, Mars was at opposition, and exceptional clear weather. The canali dissolved before Antoniadi's eyes into various "spots and blotches" on

1029-481: The Observatory until it was dismantled in 1841. A Lerebours telescope of 24.4 cm aperture was installed in 1823, at a cost of 14,500 Francs. In 1835 Arago used this telescope to observe the return of Halley's Comet that year. In 1837 the Gambey mural circle was installed, and also a transit instrument, also by Gambey. In 1857 a refracting telescope of 38 centimetres (14.96 in) aperture objective ,

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1078-574: 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 gave them somewhat the role of Director. The observatory did not have a recognised Director until 1771, before that each member could do as they pleased. Sometimes Giovanni Cassini (1671–1712) and Jacques Cassini (1712–1756) are listed as "Directors" retrospectively. The same goes for François Arago, who also

1127-577: The Paris Observatory; Meudon Observatory became part of the Paris Observatory in 1926. The Meudon Great refractor is the third largest astronomical refractor of its type in the world. The Meudon refractor is located in the Grande Coupole building, which was renovated in the early 2000s. Bernard Lyot Bernard Ferdinand Lyot ( French pronunciation: [bɛʁnaʁ fɛʁdinɑ̃ ljo] 2 7 February 1897 in Paris – 2 April 1952 in Cairo )

1176-417: The astronomers George Ellery Hale and Edward Emerson Barnard , Antoniadi could not find support for geometric canals, and felt that improvements in photography would support this. In the 1920s, Antoniadi also made observations of the rotation period of the planet Mercury . The planet was reported as appearing as "yellow orange with tinge of copper", with some grey areas as well. In the early 20th century,

1225-557: The canals could not. This idea also crumbled, as larger telescopes being used by experienced astronomers under the best conditions available were not seeing any canals, but rather finer details of the Martian surface and atmosphere. In addition, a telescope at Pic Du Midi was used to take over 1300 pictures of Mars, and among them "no trace" of canals could be seen. It was rebutted that the canals were due to differing observing (i.e. "seeing") conditions. Combined with reports from America, by

1274-465: The centuries the Paris Observatory has continued in support of astronomical activities, and in the 21st century connects multiple sites and organizations, supporting astronomy and science, past and present. 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: It maintains

1323-521: The crater peak. Paris Observatory The Paris Observatory ( French : Observatoire de Paris ; French pronunciation: [ɔbsɛʁvatwaʁ də paʁi] ), a research institution of the Paris Sciences et Lettres University , is the foremost astronomical observatory of France , and one of the largest astronomical centers in the world. Its historic building is on the Left Bank of

1372-470: The declination of the needle at Paris is about two and a half degrees to the west." The architect of the Paris Observatory was Claude Perrault whose brother, Charles , was secretary to Jean-Baptiste Colbert and superintendent of public works. Optical instruments were supplied by Giuseppe Campani . Construction of the Observatory was completed in 1671, though the buildings were extended in 1730, 1810, 1834, 1850, and 1951. The last extension incorporates

1421-476: The errant comet) was not found until the 1990s. Also the observation of planets meant, planets of the Solar system, as it was, again a century before exoplanet discovery was confirmed. The telescope had a good reputation among astronomers for an achromatic telescope in the early 20th century. Dr. Jules Janssen made the first observation with the telescope in 1893, of the pole star. He went on to make observations of

1470-450: The exact difference of longitude between the two institutions. The Paris Observatory library preserves a great number of original works and letters of the Observatory and well known astronomers. The entire collection has been inventoried in an online archive called Calames. Some of the work is now digitized on the digital library such as those of Johannes Hevelius , Jérôme Lalande and Joseph-Nicolas Delisle . The title of Director of

1519-485: The famed craftsman Giuseppe Campani. Cassini, an astronomer who worked in the early days of the Observatory, had used Campani's telescopes in the 1660s, and continued to do so when he moved to the Paris Observatory. The Marly tower, moved to the observatory in 1685 for mounting telescopes, was demolished in 1705. The Marly tower was originally made for the Versailles water supply system (see Machine de Marly ), but

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1568-636: The gardens and other site facilities. The Meudon telescope was typical of this period, missing out on becoming the largest refractor because of the Lick Observatory telescope coming online in 1888, and there were even bigger refractors, such as the Yerkes Observatory telescope, inaugurated in 1897. With the advent of chemical-based astrophotography in the 19th century, there were some difficulties in adapting Great refactors to this application. There were different solutions, and one way

1617-633: 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 observatory used the Eiffel Tower as an antenna , exchanged sustained radio signals with the United States Naval Observatory in Washington, D.C. to determine

1666-555: The observatory was integrated with the nearby Paris Observatory and became an important campus for that observatory. Even into the 21st century solar observations are conducted at the Meudon site, and the preserved Great Refractor (Grande lunette) and astronomical gardens overlooking the city of Paris have delighted visitors for decades. The site includes: After the Second World War, French astronomers began designing and building instruments for radio astronomy. A field station

1715-560: The researchers with documentation and preserves the ancient books, archives, and heritage collections of the institution. Many collections are available online. The Paris Observatory was proposed in 1665-1666 by the French Academy of Sciences , which had recently been founded by the Minister of Finance Jean-Baptiste Colbert . In 1666, King Louis XIV authorized the building of the Observatory. On Midsummer's Day 1667, members of

1764-439: The surface of Mars . The spider webs of Mars are doomed to become a myth of the past Antoniadi's use of the Meudon refractor (often called the 33 inch) added to a growing body of evidence from astronomer's around the world using large telescopes that were not seeing the canals of Mars. There was a counter-theory that small telescopes, in which the canals could sometimes be seen, were somehow better than larger telescopes, in which

1813-462: The targets such as the Moon , Jupiter, and Mars. The dome was damaged by the weather in 1999, but a grant from the French Ministry of Education supported its repair. The telescope was typically used to observe planets , double stars , comets , and asteroids . At the time asteroids are often also called minor planets , and was synonymous with asteroids; the first non-asteroid minor planets (beside

1862-404: Was Pierre Janssen , who orchestrated the construction of the large refractor. Janssen was famous for his role in the discovery of Helium in 1868, and by 1875 he was authorized to build a large astrophysical observatory. The facilities were built on the ruins of an old French palace, noted in the publication Scientific American for "beautiful view of Paris and the river seine." As one era ended

1911-523: Was a French astronomer . An avid reader of the works of Camille Flammarion , he became a member of the Société Astronomique de France in 1915 and made his first observations using the society's telescope on rue Serpente in Paris. He soon acquired a 4-inch (100 mm) telescope and soon upgraded to a 6-inch (150 mm). From graduation in 1918 until 1929, he worked as a demonstrator at

1960-399: Was designed by Claude Perrault. A dome and terrace was added in 1847. The Meudon site was constructed in the late 19th century by Jules Janssen , one of the discoverers of helium . With a million francs and permission to build on the ruins of the old royal palace, he constructed one of the grandest observatories of its day, with a focus on astronomy and solar physics. After World War I,

2009-470: Was established in 1891, and the second lens for photography was installed in 1898. The telescope was used for astronomical research for a century before being idled. Some famous astronomers of the 20th century that used the telescope include for example, Bernard Lyot and E. M. Antoniadi. Dr. Janssen made his first observation with the telescope in 1893. The first observation was of the Pole star , followed by

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2058-511: Was established in 1953, and by the late 1950s several radio instruments were established. In 1965 the Nançay radio telescope was established, a design equivalent to an almost 100-metre dish. 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), in the commune of Saint-Véran in

2107-432: Was founded in 1675. The English philosopher John Locke visited the Paris Observatory on 28 August 1677, which he recorded in his journal: "At the Observatory we saw the Moon in a twenty-two foot glass, and Jupiter, with his satellites, in the same. The most remote was on the east, and the other three on the west. We also saw Saturn and his ring, in a twelve-foot glass, and one of his satellites. Monsieur Cassini told me, that

2156-483: Was made by Secretan and Eichens. In 1875 a 120 cm aperture silver-on-glass reflecting telescope was built, for 400,000 francs (the French unit of currency at that time). This 120 cm diameter aperture telescope was a silvered glass mirror polished by Martin. However, when it was mounted it was realized the gravity altered its shape because of the mirror's weight, thus causing an image quality issue. In 1886

2205-466: Was moved to the southern gardens area near the Paris Observatory. The tower could hold the objective lens for extremely long focal length aerial telescopes. In 1732 a quadrant instrument made by Langlois was established at the Observatory. In 1804 a telescope of 8.4 cm aperture, made by Bellet, was established on the roof of the observatory. In 1807 a Short reflector telescope was acquired, and there were several instruments available including

2254-406: Was not actually a Director although he did have a de facto position of leadership and is often credited as such. The current President of the Observatory is Fabienne Casoli . The first site was the Paris headquarters established in 1667 by King Louis XIV of France. This facility had various work done on it over the centuries, and in 1927 the Meudon Observatory was added, which included

2303-497: Was only gained with a long and tiresome ski touring trek on sealskin-fitted skis, a technique mastered by Lyot, a keen sportsman and mountaineer. Accommodation on site can only be described as spartan, before a powerline, a bigger refuge and a cablecar were built in the early 1950s. In 1938, he showed a movie of the corona in action to the International Astronomical Union . In 1939, he was elected to

2352-507: Was replaced by the château Neuf, which was used until the Franco-Prussian War of 1870. The usuefull location meant the sites involvement in the activities of that war, and by the end it was left ruin. On these ruins Janssen was able to use location for the new observatory, that would house the great telescope. There are two objective lenses, one is designed for the human eye , and the other for photography. The 62 cm lens

2401-491: Was to make to separate objectives in separate tubes, with each lens having different optical properties. An example of the first case was the Great refractor of Meudon Observatory, which had a visual objective lens of 32.7 (83 cm) inches on one tube, and alongside it another tube with a lens of 24.4 inches (63 cm) intended for photographic work. The lenses are mounted in the same tube, in this case actually rectangular and

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