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Great Refractors
Great refractor refers to a large telescope with a lens, usually the largest refractor at an observatory with an equatorial mount. The preeminence and success of this style in observational astronomy defines an era in modern telescopy in the 19th and early 20th century. Great refractors were large refracting telescopes using achromatic lenses (as opposed to the mirrors of reflecting telescopes). They were often the largest in the world, or largest in a region. Despite typical designs having smaller apertures than reflectors, great refractors offered a number of advantages and were popular for astronomy. It was also popular to exhibit large refractors at international exhibits, and examples of this include the Trophy Telescope at the Great Exhibition, 1851 Great Exhibition, and the Yerkes Great Refractor at the World's Columbian Exposition, 1893 World's Fair in Chicago. A great refractor was often the centerpiece of a new 19th century observatory, but was typically used with an en ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Berlin Treptow Archenhold Sternwarte
Berlin ( ; ) is the Capital of Germany, capital and largest city of Germany, by both area and List of cities in Germany by population, population. With 3.7 million inhabitants, it has the List of cities in the European Union by population within city limits, highest population within its city limits of any city in the European Union. The city is also one of the states of Germany, being the List of German states by area, third smallest state in the country by area. Berlin is surrounded by the state of Brandenburg, and Brandenburg's capital Potsdam is nearby. The urban area of Berlin has a population of over 4.6 million and is therefore the most populous urban area in Germany. The Berlin/Brandenburg Metropolitan Region, Berlin-Brandenburg capital region has around 6.2 million inhabitants and is Germany's second-largest metropolitan region after the Rhine-Ruhr region, as well as the List of EU metropolitan areas by GDP, fifth-biggest metropolitan region by GDP in the European Union. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parallax
Parallax is a displacement or difference in the apparent position of an object viewed along two different sightline, lines of sight and is measured by the angle or half-angle of inclination between those two lines. Due to perspective (graphical), foreshortening, nearby objects show a larger parallax than farther objects, so parallax can be used to determine distances. To measure large distances, such as the distance of a planet or a star from Earth, astronomers use the principle of parallax. Here, the term ''Stellar parallax, parallax'' is the semi-angle of inclination between two sight-lines to the star, as observed when Earth is on opposite sides of the Sun in its orbit. These distances form the lowest rung of what is called "the cosmic distance ladder", the first in a succession of methods by which astronomers determine the distances to celestial objects, serving as a basis for other distance measurements in astronomy forming the higher rungs of the ladder. Because parallax ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Non-achromatic Objective
A non-achromatic objective is an objective lens which is not corrected for chromatic aberration. In telescopes they can a be pre-18th century simple single element objective lenses which were used before the invention of doublet achromatic lenses. They can also be specialty monochromatic lenses used in modern research telescopes and other instruments. Non-achromatic telescope objectives Early non-achromatic objectives Early telescope objective, such as those built by Johannes Hevelius and Christiaan Huygens and his brother Constantijn Huygens, Jr., utilized single small (2"-8") positive lenses with enormous focal lengths (up to 150 feet in length in tube telescopes and up to 600 feet in non-tube aerial telescopes). This allowed the observer to use higher magnification while limiting the interfering rainbow halos caused by chromatic aberration (the uncorrected chromatic aberration fell within the large diffraction pattern at focus). Modern non-achromatic objectives Modern instru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Percival Lowell Observing Venus From The Lowell Observatory In 1914
Perceval (, also written Percival, Parzival, Parsifal), alternatively called Peredur (), is a figure in the legend of King Arthur, often appearing as one of the Knights of the Round Table. First mentioned by the French author Chrétien de Troyes in the tale ''Perceval, the Story of the Grail'', he is best known for being the original hero in the quest for the Grail before being replaced in later literature by Galahad. Etymology and origin The earliest reference to Perceval is found in Chrétien de Troyes's first Arthurian romance ''Erec et Enide'', where, as "Percevaus li Galois" (Percevaus of Wales), he appears in a list of Arthur's knights. In another of Chrétien's romances, '' Cligés'', Perceval is a "renowned vassal" who is defeated by the knight Cligés in a tournament. He then becomes the eponymous protagonist of Chrétien's final romance, ''Perceval, the Story of the Grail''. In the Welsh romance '' Peredur son of Efrawg'', the corresponding figure goes by the nam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hugh Percy, 3rd Duke Of Northumberland
Hugh Percy, 3rd Duke of Northumberland (20 April 178511 February 1847), styled Earl Percy until 1817, was a British aristocrat and Tory politician who served as Lord Lieutenant of Ireland under the Duke of Wellington from 1829 to 1830. Background and education Northumberland was the son of Hugh Percy, 2nd Duke of Northumberland, and Frances Julia, daughter of Peter Burrell. He was educated at Eton and the University of Cambridge ( St John's College). Political career Northumberland entered parliament as the member for Buckingham in July 1806. In September of that year he was elected member for the City of Westminster, on the death of Charles James Fox. He declined to fight the seat at the general election two months later, instead being returned for Launceston. In 1807, he offered himself as a candidate for the county of Northumberland in opposition to Charles, Lord Howick (afterwards the 2nd Earl Grey), who declined to contest the seat. Percy was returned unopposed, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halley's Comet
Halley's Comet is the only known List of periodic comets, short-period comet that is consistently visible to the naked eye from Earth, appearing every 72–80 years, though with the majority of recorded apparitions (25 of 30) occurring after 75–77 years. It last appeared in the inner parts of the Solar System in 1986 and will next appear in mid-2061. Officially designated 1P/Halley, it is also commonly called Comet Halley, or sometimes simply Halley. Halley's periodic returns to the inner Solar System have been observed and recorded by astronomers around the world since at least 240 BC, but it was not until 1705 that the English astronomer Edmond Halley understood that these appearances were re-appearances of the same comet. As a result of this discovery, the comet is named after Halley. During its 1986 visit to the inner Solar System, Halley's Comet became the first comet to be observed in detail by a spacecraft, ''Giotto (spacecraft), Giotto'', providing the first obser ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thomas Grubb
Thomas Grubb (4 August 1800 – 16 September 1878) was an Irish optician and founder of the Grubb Telescope Company. He was born near Portlaw, County Waterford, Ireland, the son of William Grubb Junior, a prosperous Quaker farmer and his second wife, Eleanor Fayle. Thomas started out in 1830 in Dublin as a metal billiard-table manufacturer. He diversified into making telescopes and erected a public observatory near his factory at 1 Upper Charlemont Street, Portobello, Dublin. As makers of some of the largest and best-known telescopes of the Victorian era, the company was at the forefront of optical and mechanical engineering. His innovations for large telescopes included clock-driven polar mounts, whiffletree mirror mounting cells and Cassegrain reflector optics. Later, the manufacturing firm changed its name to Grubb-Parsons in 1925. Works Thomas Grubb's reputation as a competent telescope maker began to spread as he offered his talents to the Irish astronomical comm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paris
Paris () is the Capital city, capital and List of communes in France with over 20,000 inhabitants, largest city of France. With an estimated population of 2,048,472 residents in January 2025 in an area of more than , Paris is the List of cities in the European Union by population within city limits, fourth-most populous city in the European Union and the List of cities proper by population density, 30th most densely populated city in the world in 2022. Since the 17th century, Paris has been one of the world's major centres of finance, diplomacy, commerce, culture, Fashion capital, fashion, and gastronomy. Because of its leading role in the French art, arts and Science and technology in France, sciences and its early adoption of extensive street lighting, Paris became known as the City of Light in the 19th century. The City of Paris is the centre of the Île-de-France region, or Paris Region, with an official estimated population of 12,271,794 inhabitants in January 2023, or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Astronomical Society
The Royal Astronomical Society (RAS) is a learned society and charitable organisation, charity that encourages and promotes the study of astronomy, planetary science, solar-system science, geophysics and closely related branches of science. Its headquarters are in Burlington House, on Piccadilly in London. The society has over 4,000 members, known as fellows, most of whom are professional researchers or postgraduate students. Around a quarter of Fellows live outside the UK. The society holds monthly scientific meetings in London, and the annual National Astronomy Meeting at varying locations in the British Isles. The RAS publishes the scientific journals ''Monthly Notices of the Royal Astronomical Society'', ''Geophysical Journal International'' and ''RAS Techniques and Instruments'', along with the trade magazine ''Astronomy & Geophysics''. The RAS maintains an astronomy research library, engages in public outreach and advises the UK government on astronomy education. The socie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monthly Notices Of The Royal Astronomical Society
''Monthly Notices of the Royal Astronomical Society'' (MNRAS) is a peer-reviewed scientific journal in astronomy, astrophysics and related fields. It publishes original research in two formats: papers (of any length) and letters (limited to five pages). MNRAS publishes more articles per year than any other astronomy journal. The learned society journal has been in continuous existence since 1827 and became online only in 2020. It operates as a partnership between the Royal Astronomical Society (RAS), who select and peer-review the contents, and Oxford University Press (OUP), who publish and market the journal. Despite its name, MNRAS is no longer monthly, nor does it carry the notices of the RAS. In 2024 MNRAS became a purely gold open access journal. History The first issue of MNRAS was published on 9 February 1827 as ''Monthly Notices of the Astronomical Society of London'' and it has been in continuous publication ever since. It took its current name from the second vo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Edward Joshua Cooper
Edward Joshua Cooper (May 1798 – 23 April 1863) was an Irish landowner, politician and astronomer from Markree Castle in County Sligo. He sat in the House of Commons of the United Kingdom from 1830 to 1841 and from 1857 to 1859, but is best known for his astronomy, and as the creator of Markree Observatory. His observatory was home to the largest refracting (telescope with a lens) of the 1830s (an almost 14 inch astronomical grade Cauchoix of Paris lens, the largest in the World), and the asteroid 9 Metis was discovered there in the 1840s by his assistant. Several astronomical catalogs were also produced in the 19th century there. Early life and family Cooper was the oldest son of Edward Synge Cooper MP (1762–1830), and his wife Anne Verelst, daughter of Bengal Governor Harry Verelst (colonial governor), Harry Verelst. He was educated at The Royal School, Armagh, The Royal School in Armagh, at Eton College, Eton, and then at Christ Church, Oxford. His first marriage was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
