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Dipleidoscope
Dipleidoscope A dipleidoscope is an instrument used to determine true noon; its name comes from the Greek for ''double image viewer''. It consists of a small telescope and a prism that creates a double image of the sun. When the two images overlap, it is local true noon. The instrument is capable of determining true noon to within ten seconds. The dipleidoscope was invented by Giovanni Battista Amici in the first half of the 19th century. Edward John Dent Edward John Dent (1790–1853) was a famous English watchmaker noted for his highly accurate clocks and marine chronometers. He founded the Dent company. Early years Edward John Dent, son of John and Elizabeth Dent, was born in London on 1 ..., a chronometer and clockmaker in London, was working in the 1830s on a simple contrivance that would allow the public to set clocks correctly based on the transit of the sun (more complex and expensive transit telescopes had been developed by Ole Rømer in 1690). By 1840 he felt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Noon
Noon (or midday) is 12 o'clock in the daytime. It is written as 12 noon, 12:00 m. (for meridiem, literally 12:00 noon), 12 p.m. (for post meridiem, literally "after noon"), 12 pm, or 12:00 (using a 24-hour clock) or 1200 (military time). Solar noon is the time when the Sun appears to contact the local celestial meridian. This is when the Sun reaches its apparent highest point in the sky, at 12 noon apparent solar time and can be observed using a sundial. The local or clock time of solar noon depends on the longitude and date, with Daylight Savings Time tending to place solar noon closer to 1:00pm. Etymology The word ''noon'' is derived from Latin ''nona hora'', the ninth canonical hour of the day, in reference to the Western Christian liturgical term none, one of the seven fixed prayer times in traditional Christian denominations. The Roman and Western European medieval monastic day began at 6:00 a.m. (06:00) at the equinox by modern timekeeping, so the ninth hour star ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Telescope
An optical telescope is a telescope that gathers and focuses light mainly from the visible part of the electromagnetic spectrum, to create a magnified image for direct visual inspection, to make a photograph, or to collect data through electronic image sensors. There are three primary types of optical telescope: * Refracting telescopes, which use lenses and less commonly also prisms (dioptrics) * Reflecting telescopes, which use mirrors (catoptrics) * Catadioptric telescopes, which combine lenses and mirrors An optical telescope's ability to resolve small details is directly related to the diameter (or aperture) of its objective (the primary lens or mirror that collects and focuses the light), and its light-gathering power is related to the area of the objective. The larger the objective, the more light the telescope collects and the finer detail it resolves. People use optical telescopes (including monoculars and binoculars) for outdoor activities such as observational as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Edward John Dent
Edward John Dent (1790–1853) was a famous English watchmaker noted for his highly accurate clocks and marine chronometers. He founded the Dent company. Early years Edward John Dent, son of John and Elizabeth Dent, was born in London on 19 August 1790. He was baptised on 18 October 1790, at St. Clement Danes Church in the Strand. Edward had a younger brother, William (born 11 February 1792). The boys' mother, Elizabeth, died while they were still young – she was buried on 16 May 1793. Interest in watchmaking At the age of 14, Dent became apprenticed to his grandfather, John Wright Dent, a tallow chandler. Under the terms of the indenture – dated 20 August 1804 – John Wright Dent was expected to find suitable lodgings for his apprentice. Fortunately, Edward John Dent's cousin, Richard Rippon, was willing to have him. Rippon was an expert watchmaker and Dent became fascinated by watchmaking and less interested in the business of making and selling candles. Indeed, Dent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meridiana Iconantidiptica Di Giovanni Battista Amici Inv
Meridiana Fly S.p.A., operating as Meridiana (formerly named ''Meridiana S.p.A.''), was a privately owned Italian airline headquartered in Olbia with its main base at Olbia Costa Smeralda Airport. It operated scheduled and charter flights to domestic, European and intercontinental destinations from several Italian bases. Some of its operations were carried out by the old Air Italy under the Meridiana brand. It was owned by Qatar Airways through AQA Holding (49%) and Alisarda S.p.A. (51%), who rebranded the airline as the new Air Italy effective 1 March 2018. History Early years The company was set up with the name of Alisarda on 29 March 1963 by Aga Khan Prince Karīm al-Hussaynī with the aim of promoting tourism in Sardinia. Scheduled flights commenced in 1964. On 3 May 1991 in an Extraordinary Shareholders Meeting, the name of the company was changed to Meridiana S.p.A., and a new logo was created. These changes were made to reflect the expansion of the company's operat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prism (optics)
An optical prism is a transparent optics, optical element with flat, polished surfaces that are designed to refraction, refract light. At least one surface must be angled — elements with two parallel surfaces are ''not'' prisms. The most familiar type of optical prism is the triangular prism, which has a triangular base and rectangular sides. Not all optical prisms are prism (geometry), geometric prisms, and not all geometric prisms would count as an optical prism. Prisms can be made from any material that is transparent to the wavelengths for which they are designed. Typical materials include glass, acrylic glass, acrylic and fluorite#Optics, fluorite. A dispersive prism can be used to break white#White light, white light up into its constituent spectral colors (the colors of the rainbow) as described in the following section. Other types of prisms noted below can be used to reflection (physics), reflect light, or to split light into components with different polarization (w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Giovanni Battista Amici
Giovanni Battista Amici (; 25 March 1786 – 10 April 1863) was an Italian astronomer, microscopist, and botanist. Amici was born in Modena, in present-day Italy. After studying at Bologna, he became professor of mathematics at Modena, and in 1831 was appointed inspector-general of studies in the Duchy of Modena. A few years later he was chosen director of the observatory at Florence, where he also lectured at the museum of natural history. Amici died in Florence in 1863. His name is best known for the improvements he effected in the mirrors of reflecting telescopes and especially in the construction of the microscope. He was also a diligent and skillful observer, and busied himself not only with astronomical subjects, such as the double stars, the satellites of Jupiter and the measurement of the polar and equatorial diameters of the sun, but also with biological studies of the circulation of the sap in plants, the fructification of plants, infusoria etc. He was the first to obse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meridian Circle
The meridian circle is an instrument for timing of the passage of stars across the local meridian, an event known as a culmination, while at the same time measuring their angular distance from the nadir. These are special purpose telescopes mounted so as to allow pointing only in the meridian, the great circle through the north point of the horizon, the north celestial pole, the zenith, the south point of the horizon, the south celestial pole, and the nadir. Meridian telescopes rely on the rotation of the sky to bring objects into their field of view and are mounted on a fixed, horizontal, east–west axis. The similar transit instrument, transit circle, or transit telescope is likewise mounted on a horizontal axis, but the axis need not be fixed in the east–west direction. For instance, a surveyor's theodolite can function as a transit instrument if its telescope is capable of a full revolution about the horizontal axis. Meridian circles are often called by these names, altho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ole Rømer
Ole Christensen Rømer (; 25 September 1644 – 19 September 1710) was a Danish astronomer who, in 1676, made the first measurement of the speed of light. Rømer also invented the modern thermometer showing the temperature between two fixed points, namely the points at which water respectively boils and freezes. In scientific literature, alternative spellings such as "Roemer", "Römer", or "Romer" are common. Biography Rømer was born on 25 September 1644 in Århus to merchant and skipper Christen Pedersen (died 1663), and Anna Olufsdatter Storm ( – 1690), daughter of a well-to-do alderman. Since 1642, Christen Pedersen had taken to using the name Rømer, which means that he was from the Danish island of Rømø, to distinguish himself from a couple of other people named Christen Pedersen. There are few records of Ole Rømer before 1662, when he graduated from the old Aarhus Katedralskole (the Cathedral school of Aarhus), moved to Copenhagen and matriculated at the U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Instruments
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] |
Clocks
A clock or a timepiece is a device used to measure and indicate time. The clock is one of the oldest human inventions, meeting the need to measure intervals of time shorter than the natural units such as the day, the lunar month and the year. Devices operating on several physical processes have been used over the millennia. Some predecessors to the modern clock may be considered as "clocks" that are based on movement in nature: A sundial shows the time by displaying the position of a shadow on a flat surface. There is a range of duration timers, a well-known example being the hourglass. Water clocks, along with the sundials, are possibly the oldest time-measuring instruments. A major advance occurred with the invention of the verge escapement, which made possible the first mechanical clocks around 1300 in Europe, which kept time with oscillating timekeepers like balance wheels., pp. 103–104., p. 31. Traditionally, in horology, the term ''clock'' was used for a striki ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
