Yvon Villarceau
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Yvon Villarceau
Antoine-Joseph Yvon Villarceau (15 January 1813 – 23 December 1883) was a French astronomer, mathematician, and engineer. He constructed an equatorial meridian-instrument and an isochronometric regulator for the Paris Observatory. He wrote ''Mécanique Céleste. Expose des Méthodes de Wronski et Composantes des Forces Perturbatrices suivant les Axes Mobiles'' (Paris: Gauthier-Villars, 1881) and ''Sur l'établissement des arches de pont, envisagé au point de vue de la plus grande stabilité'' (Paris: Imprimerie Impériale, 1853). He is the eponym of Villarceau circles, which are two circular sections of a torus other than the two trivial ones. A short street in the 16th arrondissement of Paris The 16th arrondissement of Paris (''XVIe arrondissement'') is one of the 20 arrondissements of the capital city of France. In spoken French, this arrondissement is referred to as ''seizième''. The arrondissement includes part of the Arc de T ... is named after Villarceau. R ...
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Eugène Pirou
Louis Eugène Pirou (26 September 1841 – 30 September 1909) was a French photographer and filmmaker, known primarily for his portraits of celebrities and scenes from the Paris Commune. He was awarded a gold medal at the Exposition Universelle of 1889. Life and work He owned numerous studios in Paris, mostly on the Boulevard Saint-Germain, but he also operated one at an old evangelical mission on the Rue Royale. That one was sold to a photographer named Arthur Herbert, in 1889, with permission to use Pirou's name. In 1898, Herbert sold the studio to the brothers Georges and Oscar Mascré (1865-1943), who continued to use Pirou's name without his permission. Pirou lost a complicated lawsuit against the brothers, who compounded the fraud by referring to the studio as "Otto-Pirou", in reference to Otto Wegener, a Swedish-born photographer who was also not associated with them.Camille Blot-Wellens, "Eugène Pirou, portraitiste de la Belle Époque", in ''Revue de la Bibliothèqu ...
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Astronomy
Astronomy () is a natural science that studies astronomical object, celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and chronology of the Universe, evolution. Objects of interest include planets, natural satellite, moons, stars, nebulae, galaxy, galaxies, and comets. Relevant phenomena include supernova explosions, gamma ray bursts, quasars, blazars, pulsars, and cosmic microwave background radiation. More generally, astronomy studies everything that originates beyond atmosphere of Earth, Earth's atmosphere. Cosmology is a branch of astronomy that studies the universe as a whole. Astronomy is one of the oldest natural sciences. The early civilizations in recorded history made methodical observations of the night sky. These include the Babylonian astronomy, Babylonians, Greek astronomy, Greeks, Indian astronomy, Indians, Egyptian astronomy, Egyptians, Chinese astronomy, Chinese, Maya civilization, Maya, and many anc ...
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Paris Observatory
The Paris Observatory (french: Observatoire de Paris ), 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 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 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. Constitution Administrat ...
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École Centrale Paris
École Centrale Paris (ECP; also known as École Centrale or Centrale) was a French grande école in engineering and science. It was also known by its official name ''École Centrale des Arts et Manufactures''. In 2015, École Centrale Paris merged with Supélec to form CentraleSupélec, a constituent college of the University of Paris-Saclay. Founded in 1829, it was among the most prestigious and selective grandes écoles. Rooted in rich entrepreneurial tradition since the industrial revolution era, it served as the cradle for top-level engineers and executives who continue to constitute a major part of the industry leadership in France. Since the 19th century, its model of education for training generalist engineers inspired the establishment of several engineering institutes around the world, such as the École Polytechnique Fédérale de Lausanne in Switzerland, Faculté polytechnique de Mons in Belgium, as well as other member schools of the Ecole Centrales Group alliance ...
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Astronomer
An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, natural satellite, moons, comets and galaxy, galaxies – in either observational astronomy, observational (by analyzing the data) or theoretical astronomy. Examples of topics or fields astronomers study include planetary science, Sun, solar astronomy, the Star formation, origin or stellar evolution, evolution of stars, or the galaxy formation and evolution, formation of galaxies. A related but distinct subject is physical cosmology, which studies the Universe as a whole. Types Astronomers usually fall under either of two main types: observational astronomy, observational and theoretical astronomy, theoretical. Observational astronomers make direct observations of Astronomical object, celestial objects and analyze the data. In contrast, theoretical astronomers create and investigate C ...
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Meridian (astronomy)
In astronomy, the meridian is the great circle passing through the celestial poles, as well as the zenith and nadir of an observer's location. Consequently, it contains also the north and south points on the horizon, and it is perpendicular to the celestial equator and horizon. Meridians, celestial and geographical, are determined by the pencil of planes passing through the Earth's rotation axis. For a location ''not'' at a geographical pole, there is a unique meridian plane in this axial-pencil through that location. The intersection of this plane with Earth's surface is the '' geographical meridian'', and the intersection of the plane with the celestial sphere is the celestial meridian for that location and time. There are several ways to divide the meridian into semicircles. In the horizontal coordinate system, the observer's meridian is divided into halves terminated by the horizon's north and south points. The observer's upper meridian passes through the zenith while the l ...
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Villarceau Circles
In geometry, Villarceau circles () are a pair of circles produced by cutting a torus obliquely through the center at a special angle. Given an arbitrary point on a torus, four circles can be drawn through it. One is in a plane parallel to the equatorial plane of the torus and another perpendicular to that plane (these are analogous to lines of latitude and longitude on the Earth). The other two are Villarceau circles. They are obtained as the intersection of the torus with a plane that passes through the center of the torus and touches it tangentially at two antipodal points. If one considers all these planes, one obtains two families of circles on the torus. Each of these families consists of disjoint circles that cover each point of the torus exactly once and thus forms a 1-dimensional foliation of the torus. The Villarceau circles are named after the French astronomer and mathematician Yvon Villarceau (1813–1883) who wrote about them in 1848. Mannheim (1903) showed that t ...
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Torus
In geometry, a torus (plural tori, colloquially donut or doughnut) is a surface of revolution generated by revolving a circle in three-dimensional space about an axis that is coplanar with the circle. If the axis of revolution does not touch the circle, the surface has a ring shape and is called a torus of revolution. If the axis of revolution is tangent to the circle, the surface is a horn torus. If the axis of revolution passes twice through the circle, the surface is a spindle torus. If the axis of revolution passes through the center of the circle, the surface is a degenerate torus, a double-covered sphere. If the revolved curve is not a circle, the surface is called a ''toroid'', as in a square toroid. Real-world objects that approximate a torus of revolution include swim rings, inner tubes and ringette rings. Eyeglass lenses that combine spherical and cylindrical correction are toric lenses. A torus should not be confused with a '' solid torus'', which is formed by r ...
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16th Arrondissement Of Paris
The 16th arrondissement of Paris (''XVIe arrondissement'') is one of the 20 arrondissements of the capital city of France. In spoken French, this arrondissement is referred to as ''seizième''. The arrondissement includes part of the Arc de Triomphe, and a concentration of museums between the and the , complemented in 2014 by the Fondation Louis Vuitton. With its ornate 19th-century buildings, large avenues, prestigious schools, museums, and various parks, the arrondissement has long been known as one of French high society's favourite places of residence (comparable to London's Kensington and Chelsea or Berlin's Charlottenburg) to such an extent that the phrase () has been associated with great wealth in French popular culture. Indeed, the 16th arrondissement of Paris is France's third richest district for average household income, following the 7th, and , both adjacent. The 16th arrondissement hosts several large sporting venues, including: the , which is the stadium w ...
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P1170673 Paris XVI Rue Yvon-Villarceau Rwk
P117 may refer to: * , a patrol boat of the Mexican Navy * C19orf70, chromosome 19 open reading frame 70, a protein * Papyrus 117, a biblical manuscript * P117, a state regional road in Latvia {{disambiguation ...
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19th-century French Astronomers
The 19th (nineteenth) century began on 1 January 1801 (Roman numerals, MDCCCI), and ended on 31 December 1900 (Roman numerals, MCM). The 19th century was the ninth century of the 2nd millennium. The 19th century was characterized by vast social upheaval. Slavery was abolitionism, abolished in much of Europe and the Americas. The Industrial Revolution, First Industrial Revolution, though it began in the late 18th century, expanding beyond its British homeland for the first time during this century, particularly remaking the economies and societies of the Low Countries, the Rhineland, Northern Italy, and the Northeastern United States. A few decades later, the Second Industrial Revolution led to ever more massive urbanization and much higher levels of productivity, profit, and prosperity, a pattern that continued into the 20th century. The Gunpowder empires, Islamic gunpowder empires fell into decline and European imperialism brought much of South Asia, Southeast Asia, and almost ...
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