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Secretan (company)
Secretan was a company based in Paris, France that manufactured telescopes and other scientific instruments. History In 1845, Marc Secretan (1804–1867), a Swiss mathematician, and Noël Paymal Lerebours (1807–1873), a French optician, established a firm in Paris that manufactured precision instruments. In 1854, Secretan became the sole owner of the company, which continued to operate under the name Lerebours & Secretan. With popular interest in astronomy growing, the French physicist Léon Foucault (1819–1868) entered into an exclusive contract with Secretan for the commercialization of a reflecting telescope. Upon the death of Secretan in 1867, the company’s management first passed to his son Auguste François (1833–1874), and then to Auguste’s cousin Georges Emmanuel Secrétan (1837–1906). Around 1889, Georges Secrétan moved the company’s workshops to 30 rue du Faubourg Saint-Jacques, near the Paris Observatory and appointed Raymond Augustin Mailhat (1862 †... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Instrument
An optical instrument (or "optic" for short) is a device that processes light waves (or photons), either to enhance an image for viewing or to analyze and determine their characteristic properties. Common examples include periscopes, microscopes, telescopes, and cameras. Image enhancement The first optical instruments were telescopes used for magnification of distant images, and microscopes used for magnifying very tiny images. Since the days of Galileo and Van Leeuwenhoek, these instruments have been greatly improved and extended into other portions of the electromagnetic spectrum. The binocular device is a generally compact instrument for both eyes designed for mobile use. A camera could be considered a type of optical instrument, with the pinhole camera and camera obscura being very simple examples of such devices. Analysis Another class of optical instrument is used to analyze the properties of light or optical materials. They include: *Interferometer for measuring the in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paris
Paris () is the capital and most populous city of France, with an estimated population of 2,165,423 residents in 2019 in an area of more than 105 km² (41 sq mi), making it the 30th most densely populated city in the world in 2020. Since the 17th century, Paris has been one of the world's major centres of finance, diplomacy, commerce, fashion, gastronomy, and science. For its leading role in the arts and sciences, as well as its very early system of street lighting, in the 19th century it became known as "the City of Light". Like London, prior to the Second World War, it was also sometimes called the capital of the world. The City of Paris is the centre of the Île-de-France region, or Paris Region, with an estimated population of 12,262,544 in 2019, or about 19% of the population of France, making the region France's primate city. The Paris Region had a GDP of €739 billion ($743 billion) in 2019, which is the highest in Europe. According to the Economist Intelli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
France
France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pacific and Indian Oceans. Its Metropolitan France, metropolitan area extends from the Rhine to the Atlantic Ocean and from the Mediterranean Sea to the English Channel and the North Sea; overseas territories include French Guiana in South America, Saint Pierre and Miquelon in the North Atlantic, the French West Indies, and many islands in Oceania and the Indian Ocean. Due to its several coastal territories, France has the largest exclusive economic zone in the world. France borders Belgium, Luxembourg, Germany, Switzerland, Monaco, Italy, Andorra, and Spain in continental Europe, as well as the Kingdom of the Netherlands, Netherlands, Suriname, and Brazil in the Americas via its overseas territories in French Guiana and Saint Martin (island), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telescopes
A telescope is a device used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation. Originally meaning only an optical instrument using lenses, curved mirrors, or a combination of both to observe distant objects, the word ''telescope'' now refers to a wide range of instruments capable of detecting different regions of the electromagnetic spectrum, and in some cases other types of detectors. The first known practical telescopes were refracting telescopes with glass lenses and were invented in the Netherlands at the beginning of the 17th century. They were used for both terrestrial applications and astronomy. The reflecting telescope, which uses mirrors to collect and focus light, was invented within a few decades of the first refracting telescope. In the 20th century, many new types of telescopes were invented, including radio telescopes in the 1930s and infrared telescopes in the 1960s. Etymology The word ''telescope'' was coine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Noël Paymal Lerebours
Noël Marie Paymal Lerebours (16 February 1807 – 23 July 1873) was a French optician and daguerreotypist. He is best known today for his ''Excursions Daguerriennes'', books of views of the world's monuments, based on early photographs redrawn by hand as Aquatint engravings. Early life Lerebours was born in Paris of an unknown father. His mother, Marie Jeanne Françoise Paymal, a seamstress from Vitry-sur-Marne, worked in Rue Froidmanteau, Tuileries, Paris. She married Jean Lerebours, an optician, who adopted the child on 11 June 1836. On the death of his adoptive father, Lerebours took over the optician's shop in the Place du Pont-Neuf and formed a partnership with Marc Secretan in 1845, the firm being known as ''Lerebours et Secretan''. As well as producing high quality lenses and glasses for astronomical observatories, during the years 1840-1850 Lerebours was equally interested in improving daguerreotype photography. Career In the autumn of 1839, Lerebours used his skil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Léon Foucault
Jean Bernard Léon Foucault (, ; ; 18 September 1819 – 11 February 1868) was a French physicist best known for his demonstration of the Foucault pendulum, a device demonstrating the effect of Earth's rotation. He also made an early measurement of the speed of light, discovered eddy currents, and is credited with naming the gyroscope. Early years The son of a publisher, Foucault was born in Paris on 18 September 1819. After an education received chiefly at home, he studied medicine, which he abandoned in favour of physics due to a blood phobia. He first directed his attention to the improvement of Louis Daguerre's photographic processes. For three years he was experimental assistant to Alfred Donné (1801–1878) in his course of lectures on microscopic anatomy. With Hippolyte Fizeau he carried out a series of investigations on the intensity of the light of the sun, as compared with that of carbon in the arc lamp, and of lime in the flame of the oxyhydrogen blowpipe; on the int ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Raymond Augustin Mailhat
Raymond Augustin Jean-Baptiste Mailhat (28 March 1862 – 22 April 1923) was a French manufacturer of telescopes and precision optical instruments. Biography Raymond Mailhat was born on 28 March 1862 in Saurat ( Ariège), the son of Jean Benjamin Mailhat, an illiterate shoemaker. After studying under Paul Gautier (1842-1909), Raymond became the director of the Secrétan company’s optics workshop in Paris on 1 January 1889. In 1894, Mailhat bought part of those workshops and established his own business. The Maison Mailhat manufactured a wide variety of equipment for both scientists and amateurs: * Astronomical and photographic lenses * Mirrors (flat, spherical and parabolic) * Equatorial mount refractor telescopes and photographic telescopes * Meridian circles (fixed and portable) * Astronomical and geodesical equipment for scientific missions and explorers * Simple refractor and equatorial telescopes for amateur comet hunters * Equipment for physicists * Coelostats ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amateur Astronomy
Amateur astronomy is a hobby where participants enjoy observing or imaging celestial objects in the sky using the unaided eye, binoculars, or telescopes. Even though scientific research may not be their primary goal, some amateur astronomers make contributions in doing citizen science, such as by monitoring variable stars, double stars, sunspots, or occultations of stars by the Moon or asteroids, or by discovering transient astronomical events, such as comets, galactic novae or supernovae in other galaxies. Amateur astronomers do not use the field of astronomy as their primary source of income or support, and usually have no professional degree in astrophysics or advanced academic training in the subject. Most amateurs are hobbyists, while others have a high degree of experience in astronomy and may often assist and work alongside professional astronomers. Many astronomers have studied the sky throughout history in an amateur framework; however, since the beginning of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
