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Denis Albert Bardou
Denis Albert Bardou (15 February 1841 – 14 March 1893) was a French manufacturer of precision optical instruments. Early life He was born in Paris, the son of Pierre Gabriel Bardou, optician, and Gertrude Aglaé Anna Guichard. Denis Albert's grandfather had founded the Maison Bardou in 1819, an optical company in Paris, which had then passed to his father. Career In 1865, Denis Albert assumed control of the family business. The company was located at his residence at 55, rue de Chabrol. The company manufactured and sold astronomical telescopes, spyglasses, binoculars, microscopes and opera glasses. The telescopes included both Equatorial mount, equatorial and Altazimuth mount, azimuthal models with silvered glass mirrors (10, 16, 20 cm). Between 1867 and 1891 the Bardou company won numerous awards at expositions of Le Havre, Philadelphia, and Paris, including a gold medal at the Exposition Universelle (1889), Exposition Universelle in Paris in 1889. It furnished optica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brackets
A bracket is either of two tall fore- or back-facing punctuation marks commonly used to isolate a segment of text or data from its surroundings. Typically deployed in symmetric pairs, an individual bracket may be identified as a 'left' or 'right' bracket or, alternatively, an "opening bracket" or "closing bracket", respectively, depending on the directionality of the context. Specific forms of the mark include parentheses (also called "rounded brackets"), square brackets, curly brackets (also called 'braces'), and angle brackets (also called 'chevrons'), as well as various less common pairs of symbols. As well as signifying the overall class of punctuation, the word "bracket" is commonly used to refer to a specific form of bracket, which varies from region to region. In most English-speaking countries, an unqualified word "bracket" refers to the parenthesis (round bracket); in the United States, the square bracket. Various forms of brackets are used in mathematics, with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
Telescope Manufacturers
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jaén, Spain
Jaén () is the urban capital city of the province of Jaén, in the autonomous community of Andalusia, Spain. The city of Jaén is the administrative and industrial centre for the province. Industrial establishments in the city include chemical works, tanneries, distilleries, cookie factories, textile factories, as well as agricultural and olive oil processing machinery industry. The layout of Jaén is determined by its position in the hills of the Santa Catalina mountains, with steep, narrow streets, in the historical central city district. Its population is 112,757 (2020), about one-sixth of the population of the province. Recently Jaén has had a great increase in cultural tourism, having received 604,523 tourists along the year 2015, 10% more than in 2014. The city is also known as the ''World Capital of Olive Oil'', because it is the biggest producer of the oil, known by locals as ''liquid gold''. Etymology The name is most likely derived from the Roman name ''Villa G ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Camille Flammarion
Nicolas Camille Flammarion Fellow of the Royal Astronomical Society, FRAS (; 26 February 1842 – 3 June 1925) was a French astronomer and author. He was a prolific author of more than fifty titles, including popular science works about astronomy, several notable early science fiction novels, and works on Parapsychology, psychical research and related topics. He also published the magazine ''L'Astronomie (magazine), L'Astronomie'', starting in 1882. He maintained a private Camille Flammarion Observatory, observatory at Juvisy-sur-Orge, France. Biography Camille Flammarion was born in Val-de-Meuse, Montigny-le-Roi, Haute-Marne, France. He was the brother of Ernest Flammarion (1846–1936), the founder of the Groupe Flammarion publishing house. In 1858 he became a computer (job description), computer at the Paris Observatory. He was a founder and the first president of the ''Société astronomique de France'', which originally had its own independent journal, L'Astronomie (magazi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
6th Arrondissement Of Paris
The 6th arrondissement of Paris (''VIe arrondissement'') is one of the 20 arrondissements of the capital city of France. In spoken French, it is referred to as ''le sixième''. The arrondissement, called Luxembourg in a reference to the seat of the Senate and its garden, is situated on the Rive Gauche of the River Seine. It includes educational institutions such as the École nationale supérieure des Beaux-Arts, the École des hautes études en sciences sociales and the Institut de France, as well as Parisian monuments such as the Odéon-Théâtre de l'Europe, the Pont des Arts, which links the 1st and 6th arrondissements over the Seine, Saint-Germain Abbey and Saint-Sulpice Church. This central arrondissement, which includes the historic districts of Saint-Germain-des-Prés (surrounding the abbey founded in the 6th century) and Luxembourg (surrounding the Palace and its Gardens), has played a major role throughout Parisian history and is well known for its café culture and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Observatory Of The Rue Serpente
The Observatory of the rue Serpente was an astronomical observatory owned and operated by the Société Astronomique de France (the French Astronomical Society) in the historic Latin Quarter of Paris. It operated between 1890 until 1968, when it was transferred to a new location at the nearby Astronomy Tower of the Sorbonne. Origin On 4 April 1887, the headquarters of the recently founded Société Astronomique de France was established at the '' Hôtel des Sociétés Savantes'', a building that housed different scientific societies, at 28 rue Serpente in the 6th arrondissement of Paris. At the suggestion of Camille Flammarion, the society's founder, an observatory was built on the building's roof. Its purpose was to popularize astronomy and it would be open to all members of the Society. The observatory eventually included two domes (which still exist today), a meridian room, a meeting room, and a library, and it occupied the entire upper floor of the building. Over the years, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Focal Length
The focal length of an optical system is a measure of how strongly the system converges or diverges light; it is the inverse of the system's optical power. A positive focal length indicates that a system converges light, while a negative focal length indicates that the system diverges light. A system with a shorter focal length bends the rays more sharply, bringing them to a focus in a shorter distance or diverging them more quickly. For the special case of a thin lens in air, a positive focal length is the distance over which initially collimated (parallel) rays are brought to a focus, or alternatively a negative focal length indicates how far in front of the lens a point source must be located to form a collimated beam. For more general optical systems, the focal length has no intuitive meaning; it is simply the inverse of the system's optical power. In most photography and all telescopy, where the subject is essentially infinitely far away, longer focal length (lower ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Refracting Telescope
A refracting telescope (also called a refractor) is a type of optical telescope that uses a lens as its objective to form an image (also referred to a dioptric telescope). The refracting telescope design was originally used in spyglasses and astronomical telescopes but is also used for long-focus camera lenses. Although large refracting telescopes were very popular in the second half of the 19th century, for most research purposes, the refracting telescope has been superseded by the reflecting telescope, which allows larger apertures. A refractor's magnification is calculated by dividing the focal length of the objective lens by that of the eyepiece. Refracting telescopes typically have a lens at the front, then a long tube, then an eyepiece or instrumentation at the rear, where the telescope view comes to focus. Originally, telescopes had an objective of one element, but a century later, two and even three element lenses were made. Refracting telescope is a technolog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equatorial Mount
An equatorial mount is a mount for instruments that compensates for Earth's rotation by having one rotational axis, the polar axis, parallel to the Earth's axis of rotation. This type of mount is used for astronomical telescopes and cameras. The advantage of an equatorial mount lies in its ability to allow the instrument attached to it to stay fixed on any celestial object with diurnal motion by driving one axis at a constant speed. Such an arrangement is called a sidereal or clock drive. Equatorial mounts achieve this by aligning their rotational axis with the Earth, a process known as polar alignment. Astronomical telescope mounts In astronomical telescope mounts, the equatorial axis (the ''right ascension'') is paired with a second perpendicular axis of motion (known as the ''declination''). The equatorial axis of the mount is often equipped with a motorized "'' clock drive''", that rotates that axis one revolution every 23 hours and 56 minutes in exact sync with th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Camille Flammarion Observatory
The observatory was established in Juvisy-sur-Orge in 1883 by the French astronomer and author Camille Flammarion. In March 2010, the structure was classified as a historical monument by the French Ministry of Culture. The observatory belongs to the Société astronomique de France. Building and grounds The observatory is located on Route nationale 7 (formerly the avenue de la Cour de France), close to the downtown of Juvisy. The site, which is on a prominent hilltop location, is a large parcel of land that contains several buildings, a monumental gate, gardens, and a small forest. The building housing the observatory was originally a post house constructed in 1730. In 1883–1884, Flammarion transformed the structure into an astronomical observatory by adding a large equatorial room for the telescope, a library, a scientific museum, a meteorological station and an agricultural research station. In 1899, the architect François Giamarchi was commissioned to transform the east ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
L'Astronomie (magazine)
''LAstronomie'' () is a monthly astronomy magazine published by the Société astronomique de France (SAF). Sylvain Bouley, the president of SAF, is the publication director and astronomer Fabrice Mottez is the editor-in-chief. History The magazine was established by Camille Flammarion and the first issue, dated 1882, was published on January 1, 1883. After SAF was founded in 1887, a second journal was created, called the ''Bulletin mensuel de la Société Astronomique de France''. The two publications existed in parallel up to 1894. In the December 1894 issue, Flammarion announced in an editorial that ''LAstronomie'' would cease to exist. From January 1895 to December 1910, only the ''Bulletin de la Société Astronomique de France'' was published. Starting from 1912, the ''Bulletin'' was renamed ''LAstronomie'', while preserving the volume numbering of the ''Bulletin''. Distribution The magazine is available by subscription both in France and internationally in hard copy an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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