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Chester Moore Hall
Chester Moore Hall (9 December 1703, Leigh, Essex, England – 17 March 1771, Sutton) was a British lawyer and inventor who produced the first achromatic lenses in 1729 or 1733 (accounts differ). He used the achromatic lens to build the first achromatic telescope, a refracting telescope free from chromatic aberration (colour distortion). He lived at New Hall, Sutton. His name was also spelled ''Chester Moor Hall'' and ''Chester More Hall''. The design had two elements, a crown and flint glass, that brought two wavelengths of light to a focus. Chester is noted as having made the first twin color corrected lens in 1730. See also *List of largest optical telescopes in the 18th century *John Dollond John Dollond (30 November 1761) was an English optician, known for his successful optics business and his patenting and commercialization of achromatic doublets. Biography Dollond was the son of a Huguenot refugee, a silk-weaver at Spitalfie ... (also developed achromats in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leigh-on-Sea
Leigh-on-Sea (), commonly referred to simply as Leigh, is a List of towns in England, town and civil parish within the city of Southend-on-Sea, located in the ceremonial county of Essex, England. In 2011 it had a population of 22,509. Geography Leigh-on-Sea is on the northern side of the Thames Estuary, a few miles from the open waters of the North Sea to the east, and a similar distance from the Kent coast to the south. The coastal environs of the town feature a nature reserve at Two Tree Island and a centrally located beach adjacent to Bell Wharf. At low tide Leigh's foreshore has a wide expanse of mud flats and Creek (tidal), creeks, extending offshore towards the deep water channel of the River Thames, Thames (Yantlet Channel). Leigh is from central London via road and rail networks and is part of the London commuter belt. History Origins Archaeological finds of pottery and coins from Romano-British culture, Romano-British era in the locality suggest early settlement. F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sutton, Essex
Sutton is a village and civil parish in the District of Rochford in Essex, England. It is located between the River Roach and the adjoining Borough of Southend-on-Sea, and includes the hamlet of Shopland. It has a population of 127, increasing at the 2011 Census to 135, the smallest in the District, although at the time of the Domesday Book it had a flourishing village with its own market and fair. The place-name 'Sutton' is first recorded in the Domesday Book of 1086, where it appears as ''Suttuna''. The name means 'southern town or settlement'. The place-name 'Shopland' is first attested in a list of c. 1000 AD of the manors of St Paul's Cathedral in Corpus Christi College, Cambridge (MS. 383), where it appears as ''Scopingland''. It appears as ''Scopelanda'' in the Domesday Book of 1086, and as ''Scopiland'' in the Feet of Fines in 1208. The name means 'island with a shed', the first element being the Old English ''sceoppa'', or the Middle English ''schoppe'', meaning ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Achromatic Lens
An achromatic lens or achromat is a lens (optics), lens that is designed to limit the effects of chromatic aberration, chromatic and spherical aberration. Achromatic lenses are corrected to bring two wavelengths (typically red and blue) into focus on the same plane. Wavelengths in between these two then have better focus error than could be obtained with a simple lens. The most common type of achromat is the achromatic doublet, which is composed of two individual lenses made from glasses with different amounts of Dispersion (optics), dispersion. Typically, one element is a negative (Lens (optics)#Types of simple lenses, concave) element made out of flint glass such as F2, which has relatively high dispersion, and the other is a positive (Lens (optics)#Types of simple lenses, convex) element made of Crown glass (optics), crown glass such as BK7, which has lower dispersion. The lens elements are mounted next to each other, often cemented together, and shaped so that the chromati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Achromatic Telescope
The achromatic telescope is a refracting telescope that uses an achromatic lens to correct for chromatic aberration. How it works When an image passes through a lens, the light is refracted at different angles for different wavelengths. This reflects focal lengths that are dependent on the color of the light. So, for example, at the focal plane an image may be focused at the red end of the spectrum, but blurred at the blue end. This effect is particularly noticeable the further an object lies from the central axis of the telescope. The image of a star can appear blue on one side and orange on the other. Early refracting telescopes with non-achromatic objectives were constructed with very long focal lengths to mask the chromatic aberration. An Achromatic telescope uses an achromatic lens to correct for this. An achromatic lens is a compound lenses made with two types of glass with different dispersion. One element, a ''concave'' lens made out of Flint glass, has relatively high ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromatic Aberration
In optics, chromatic aberration (CA), also called chromatic distortion, color aberration, color fringing, or purple fringing, is a failure of a lens to focus all colors to the same point. It is caused by dispersion: the refractive index of the lens elements varies with the wavelength of light. The refractive index of most transparent materials decreases with increasing wavelength. Since the focal length of a lens depends on the refractive index, this variation in refractive index affects focusing. Since the focal length of the lens varies with the color of the light different colors of light are brought to focus at different distances from the lens or with different levels of magnification. Chromatic aberration manifests itself as "fringes" of color along boundaries that separate dark and bright parts of the image. Types There are two types of chromatic aberration: ''axial'' (''longitudinal''), and ''transverse'' (''lateral''). Axial aberration occurs when different wavelengt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Encyclopædia Britannica
The is a general knowledge, general-knowledge English-language encyclopaedia. It has been published by Encyclopædia Britannica, Inc. since 1768, although the company has changed ownership seven times. The 2010 version of the 15th edition, which spans 32 volumes and 32,640 pages, was the last printed edition. Since 2016, it has been published exclusively as an online encyclopedia, online encyclopaedia. Printed for 244 years, the ''Britannica'' was the longest-running in-print encyclopaedia in the English language. It was first published between 1768 and 1771 in Edinburgh, Scotland, in three volumes. The encyclopaedia grew in size; the second edition was 10 volumes, and by its fourth edition (1801–1810), it had expanded to 20 volumes. Its rising stature as a scholarly work helped recruit eminent contributors, and the 9th (1875–1889) and Encyclopædia Britannica Eleventh Edition, 11th editions (1911) are landmark encyclopaedias for scholarship and literary ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Largest Optical Telescopes In The 18th Century
List of largest optical telescopes in the 18th century includes various refractors and reflectors that were active some time between about 1699 to 1801. It is oriented towards astronomy, not terrestrial telescopes (e.g., spyglasses). Many of the largest were metal mirror reflectors, some of which had substational apertures even for the 20th century. One problem was that many instrument makers. including William Herschel, did not pass on their mirror-making craft, and by the next century reflectors had largely been passed over in favour of small achromats (2-lens refractors). It was not until the 20th century that really large reflectors would predominate once again. The major breakthrough in the 18th century was the perfection of two and even three lens refractor telescopes, as well as the increased number of reflectors using polished metal mirrors rather than metal-coated glass, which was not developed until the mid-19th century. Selected Reflectors & Refractors The main telesc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Dollond
John Dollond (30 November 1761) was an English optician, known for his successful optics business and his patenting and commercialization of achromatic doublets. Biography Dollond was the son of a Huguenot refugee, a silk-weaver at Spitalfields, London, where he was born. He followed his father's trade, but found time to acquire a knowledge of Latin, Greek, mathematics, physics, anatomy and other subjects. In 1752 he abandoned silk-weaving and joined his eldest son, Peter Dollond (1731–1820), who in 1750 had started in business as a maker of optical instruments; this business went on to become Dollond & Aitchison. His reputation grew rapidly, and in 1761 he was appointed optician to the king. In 1758 he published an "Account of some experiments concerning the different refrangibility of light", describing the experiments that led him to the achievement with which his name is specially associated, the discovery of a means of constructing achromatic lenses by the combinati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1703 Births
In the Swedish calendar it was a common year starting on Thursday, one day ahead of the Julian and ten days behind the Gregorian calendar. Events January–March * January 9 – The Jamaican town of Port Royal, a center of trade in the Western Hemisphere and at this time the largest city in the Caribbean, is destroyed by a fire. British ships in the harbor are able to rescue much of the merchandise that has been unloaded on the docks, but the inventory in market-places in town is destroyed."Fires, Great", in ''The Insurance Cyclopeadia: Being an Historical Treasury of Events and Circumstances Connected with the Origin and Progress of Insurance'', Cornelius Walford, ed. (C. and E. Layton, 1876) p47 * January 14 – 1703 Apennine earthquakes: The magnitude 6.7 Norcia earthquake affects Central Italy with a maximum Mercalli intensity of XI (''Extreme''). With a death toll of 6,240–9,761, it is the first in a sequence of three destructive events. * January 16 &nda ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1771 Deaths
Events January– March * January 5 – The Great Kalmyk people, Kalmyk (Torghut) Migration is led by Ubashi Khan, from the east bank of the Lower Volga River back to the homeland of Dzungaria, at this time under Qing dynasty rule. * January 9 – Emperor Go-Momozono accedes to the throne of Tokugawa shogunate Japan following his aunt's abdication. * February 12 – Upon the death of Adolf Frederick, King of Sweden, Adolf Frederick, he is succeeded as King of Sweden by his son Gustav III of Sweden, Gustav III. At the time, however, Gustav is unaware of this, since he is abroad in Paris; the news of his father's death reaches him about a month later. * March – War of the Regulation: Royal Colony of North Carolina, North Carolina Governor William Tryon raises a militia to put down the long-running uprising of backcountry militias against North Carolina's colonial government. * March 12 – The North Carolina General Assembly establishes Wake County, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Members Of The Inner Temple
Member may refer to: * Military jury, referred to as "Members" in military jargon * Element (mathematics), an object that belongs to a mathematical set * In object-oriented programming, a member of a class ** Field (computer science), entries in a database ** Member variable, a variable that is associated with a specific object * Limb (anatomy), an appendage of the human or animal body ** Euphemism for penis * Structural component of a truss, connected by nodes * User (computing), a person making use of a computing service, especially on the Internet * Member (geology), a component of a geological formation * Member of parliament * The Members, a British punk rock band * Meronymy, a semantic relationship in linguistics * Church membership, belonging to a local Christian congregation, a Christian denomination and the universal Church * Member, a participant in a Club (organization), club or learned society See also * * {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
18th-century British Astronomers
The 18th century lasted from 1 January 1701 (represented by the Roman numerals MDCCI) to 31 December 1800 (MDCCC). During the 18th century, elements of Enlightenment thinking culminated in the Atlantic Revolutions. Revolutions began to challenge the legitimacy of monarchical and aristocratic power structures. The Industrial Revolution began mid-century, leading to radical changes in human society and the environment. The European colonization of the Americas and other parts of the world intensified and associated mass migrations of people grew in size as part of the Age of Sail. During the century, slave trading expanded across the shores of the Atlantic Ocean, while declining in Russia and China. Western historians have occasionally defined the 18th century otherwise for the purposes of their work. For example, the "short" 18th century may be defined as 1715–1789, denoting the period of time between the death of Louis XIV of France and the start of the French Revolut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
