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John Hadley
John Hadley (16 April 1682 – 14 February 1744) was an English mathematician, and laid claim to the invention of the octant, two years after Thomas Godfrey claimed the same. Biography He was born in Bloomsbury, London the eldest son of George Hadley of Osidge, East Barnet, Hertfordshire and his wife Katherine FitzJames. His younger brother George Hadley became a noted meteorologist. In 1717 John became a member (and later vice-president) of the Royal Society of London. In 1729 he inherited his father's East Barnet estate. He died in East Barnet in 1744 and is buried in the local churchyard with other members of his family. He had married Elizabeth, daughter of Thomas Hodges, FRS (former Attorney General of Barbados) and had one child, a son and heir John, born in 1738. Work In 1730 Hadley invented the reflecting octant, which could be used to measure the altitude of the sun or other celestial objects above the horizon at sea. A mobile arm carrying a mirror and piv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bloomsbury
Bloomsbury is a district in the West End of London. It is considered a fashionable residential area, and is the location of numerous cultural, intellectual, and educational institutions. Bloomsbury is home of the British Museum, the largest museum in the United Kingdom, and several educational institutions, including University College London and a number of other colleges and institutes of the University of London as well as its central headquarters, the New College of the Humanities, the University of Law, the Royal Academy of Dramatic Art, the British Medical Association and many others. Bloomsbury is an intellectual and literary hub for London, as home of world-known Bloomsbury Publishing, publishers of the ''Harry Potter'' series, and namesake of the Bloomsbury Set, a group of British intellectuals which included author Virginia Woolf, biographer Lytton Strachey, and economist John Maynard Keynes. Bloomsbury began to be developed in the 17th century under the Earls o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parabolic Reflector
A parabolic (or paraboloid or paraboloidal) reflector (or dish or mirror) is a reflective surface used to collect or project energy such as light, sound, or radio waves. Its shape is part of a circular paraboloid, that is, the surface generated by a parabola revolving around its axis. The parabolic reflector transforms an incoming plane wave travelling along the axis into a spherical wave converging toward the focus. Conversely, a spherical wave generated by a point source placed in the focus is reflected into a plane wave propagating as a collimated beam along the axis. Parabolic reflectors are used to collect energy from a distant source (for example sound waves or incoming star light). Since the principles of reflection are reversible, parabolic reflectors can also be used to collimate radiation from an isotropic source into a parallel beam. In optics, parabolic mirrors are used to gather light in reflecting telescopes and solar furnaces, and project a beam of li ... [...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, are listings of what were, for the time period of the 18th century, large optical telescopes. The list includes various refractor and reflector that were active some time between about 1699 to 1801. It is oriented towards astronomy, not terrestrial telescopes (e.g. spyglass). Many of the largest were metal mirror reflectors, some of which had substational apertures even for the 20th century. One problems was that many instrument makers including 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. Some of the achievements in astronomy of the 19th century telescopes include the discovery of the planet Uranus, the Messier catalog, and overall increased detections of comets, stars, star catalogs, and other charting. The maj ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oasis Academy Hadley
Oasis Academy Hadley is an all-through academy school located in the Ponders End area of the London Borough of Enfield, England run by Oasis Community Learning. It is the second Oasis academy in the London and has close links with Oasis Academy Enfield. It opened on 7 September 2009. It opened in the existing buildings of Albany School and the Primary Phase opened its reception class in September 2010. Mid January 2013, the new building in Ponders End was opened. Description Oasis Academy Enfield was an early member is part of the Oasis Community Learning group, and evangelical Christian charity. The trust have guided forty schools out of special measures. 19 per cent of the 52 Oasis academies classified as failing. The trust's founder Reverend Steve Chalke says "Turning round a school is sometimes a quick fix, it really, truly is. And sometimes it’s a really long, hard, hard job". Governance On becoming an Oasis academy, a local board of management provided by the regional h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ponders End
Ponders End is the southeasternmost part of Enfield, north London, centred on the Hertford Road. Situated to the west of the River Lee Navigation, it became industrialised through the 19th century, similar to the Lea Valley in neighbouring Edmonton and Brimsdown, with manufacturing giving way to warehousing in the late-20th century. The area consists heavily of social housing, with streets also lined with 19th and early-20th century suburban terraced housing. As a result of increased levels of immigration, the area has become the most ethnically diverse part of Enfield, with the majority of the population now belonging to an ethnic minority background as first recorded in the 2011 census. The area is undergoing large-scale regeneration, with the high-rise Alma Road Estate currently undergoing demolition and redevelopment by Countryside Properties. The population of Ponders End was 15,664 as of 2011. Geography Elevations range from to above sea level, uniformly dropping fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oasis Trust
Oasis Charitable Trust, commonly known as Oasis, is a UK-based Christian registered charity. It was founded by the Reverend Steve Chalke in September 1985. Chalke had been assistant minister at Tonbridge Baptist Church, Kent, for four years. He left this job with the aim of setting up a hostel for homeless young people. Oasis now has over 5,000 staff in the UK as well as thousands more volunteers. Since its foundation Oasis has also developed into a family of charities now working on four continents (11 countries) around the world, with the goal of delivering housing, education, training, youthwork and healthcare. Oasis is now a significant voluntary sector provider, delivering services for local authorities and national governments, as well as self funded initiatives. Oasis currently works in 51 local neighbourhoods – 35 of which are in the UK. Oasis Church Waterloo In 2003, under Steve Chalke's leadership, Oasis, having become responsible for the buildings of Christ Churc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moon
The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of Australia). The Moon is a planetary-mass object with a differentiated rocky body, making it a satellite planet under the geophysical definitions of the term and larger than all known dwarf planets of the Solar System. It lacks any significant atmosphere, hydrosphere, or magnetic field. Its surface gravity is about one-sixth of Earth's at , with Jupiter's moon Io being the only satellite in the Solar System known to have a higher surface gravity and density. The Moon orbits Earth at an average distance of , or about 30 times Earth's diameter. Its gravitational influence is the main driver of Earth's tides and very slowly lengthens Earth's day. The Moon's orbit around Earth has a sidereal period of 27.3 days. During each s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rima Hadley
Rima, also known as Rima the Jungle Girl, is the fictional heroine of W. H. Hudson's 1904 novel '' Green Mansions: A Romance of the Tropical Forest''. In it, Rima, a primitive girl of the shrinking rain forest of South America, meets Abel, a political fugitive. A film adaptation of '' Green Mansions'' was made in 1959 starring Audrey Hepburn. In 1974, the character was adapted into the comic book ''Rima the Jungle Girl'', published by DC Comics. Though ''Rima the Jungle Girl'' ceased publication in 1975, the comic book version of Rima appeared in several episodes of Hanna-Barbera's popular Saturday morning cartoon series, ''The All-New Super Friends Hour'', between 1977 and 1980. Novel Like her literary cousins Tarzan and Mowgli, Rima sprang from an Edwardian adventure novel; in her case, '' Green Mansions: A Romance of the Tropical Forest'', by W. H. Hudson, published in 1904. Hudson was an Argentine-British naturalist who wrote many classic books about the ecology of South A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mons Hadley
Mons Hadley is a massif in the northern portion of the Montes Apenninus, a range in the northern hemisphere of the Moon. It has a height of above the adjacent plain and a maximum diameter of 25 km at the base. To the southwest of this mountain is a valley that served as the landing site for the Apollo 15 expedition. To the southwest of this same valley is the slightly smaller Mons Hadley Delta (δ) peak with a height of about 3.5 km above the valley floor. Mons Hadley Delta was visited and sampled by the astronauts, but Mons Hadley itself was only photographed from the surface. To the west of these peaks is the sinuous Rima Hadley rille. These features were named after the English mathematician John Hadley. Rima Hadley This sinuous lunar rille follows a course generally to the northeast, toward the Mons Hadley peak, for which it is named. This feature is centered at selenographic coordinates 25.0° N, 3.0° E, and lies within a diameter of 80 km. It ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gregorian Telescope
The Gregorian telescope is a type of reflecting telescope designed by Scottish mathematician and astronomer James Gregory in the 17th century, and first built in 1673 by Robert Hooke. James Gregory was a contemporary of Isaac Newton. Both often worked simultaneously on similar projects. Gregory's design was published in 1663 and pre-dates the first practical reflecting telescope, the Newtonian telescope, built by Sir Isaac Newton in 1668."Isaac Newton: adventurer in thought", by Alfred Rupert Hallpage 67 However, Gregory's design was only a theoretical description, and he never actually constructed the telescope. It was not successfully built until five years after Newton's first reflecting telescope. History The Gregorian telescope is named after the James Gregory design, which appeared in his 1663 publication (The Advance of Optics). Similar theoretical designs have been found in the writings of Bonaventura Cavalieri ( (On Burning Mirrors), 1632) and Marin Mersenne (, 1636 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aerial Telescope
An aerial telescope is a type of very long focal length refracting telescope, built in the second half of the 17th century, that did not use a tube. Instead, the objective was mounted on a pole, tree, tower, building or other structure on a swivel ball-joint. The observer stood on the ground and held the eyepiece, which was connected to the objective by a string or connecting rod. By holding the string tight and maneuvering the eyepiece, the observer could aim the telescope at objects in the sky. The idea for this type of telescope may have originated in the late 17th century with the Dutch mathematician, astronomer and physicist Christiaan Huygens and his brother Constantijn Huygens, Jr., though it is not clear if they actually invented it. Invention and application Very long "tubed" telescopes Telescopes built in the 17th and early 18th century used single element non-achromatic objective lenses that suffered from interfering rainbow halos (chromatic aberration) introdu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primary Mirror
A primary mirror (or primary) is the principal light-gathering surface (the objective) of a reflecting telescope. Description The primary mirror of a reflecting telescope is a spherical or parabolic shaped disks of polished reflective metal ( speculum metal up to the mid 19th century), or in later telescopes, glass or other material coated with a reflective layer. One of the first known reflecting telescopes, Newton's reflector of 1668, used a 3.3 cm polished metal primary mirror. The next major change was to use silver on glass rather than metal, in the 19th century such was with the Crossley reflector. This was changed to vacuum deposited aluminum on glass, used on the 200-inch Hale telescope. Solid primary mirrors have to sustain their own weight and not deform under gravity, which limits the maximum size for a single piece primary mirror. Segmented mirror configurations are used to get around the size limitation on single primary mirrors. For example, the Gia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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