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Arthur Bleksley
Arthur Edward Herbert Bleksley (1908, Matatiele – 1984) was a South African Professor of Applied Mathematics and an astronomer. Bleksley's early research involved the astrophysics and astronomy of variable stars. He encouraged science awareness in South Africa by publishing articles about science, by being on a popular radio show, and through his presentations at the Johannesburg Planetarium. Education and career Bleksley was born in the Eastern Cape and attended the Outeniqua High School in George. After matriculation he studied at Stellenbosch University and graduated ''cum laude'' in 1927 and went on to obtain his M.Sc. in 1929, winning the Van der Horst Prize. In 1930 he joined the Solar Research Station run by the National Geographic Society and the Smithsonian Institution at Brukkaros, the caldera of an extinct volcano in South West Africa (Namibia). American researcher William H. Hoover and his colleague Frederick Atwood Greeley, ran an observatory on the mountain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Matatiele
Matatiele is a town located in the northern part of the Eastern Cape Province of South Africa. According to the South African National Census of 2011, its 12,466 residents (1,113.44 per km²) and 4,107 households (366.83 per km²) make Matatiele the largest populated town in the Matatiele Local Municipality. Once dominated by wetlands and marshes, Matatiele derives its name from a portmanteau word of the Sotho language words “matata”, meaning wild ducks, and “ile”, meaning gone and the Phuthi language words "mati" meaning water and "ayile" meaning dried out. When taken together, Matatiele conveys a message that “ducks have flown” because of a "dried out wetlands and marshes". In Phuthi language, the town name is pronounced “Matatiyela”. The common informal name for the town in any of the languages mentioned, including English, is “Matat”. And those born here call it “Sweet Matat”. Matatiele's area of – tucked in the shadows of the Matatiele Mountains ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chile
Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east and the Pacific Ocean to the west. Chile covers an area of , with a population of 17.5 million as of 2017. It shares land borders with Peru to the north, Bolivia to the north-east, Argentina to the east, and the Drake Passage in the far south. Chile also controls the Pacific islands of Juan Fernández, Isla Salas y Gómez, Desventuradas, and Easter Island in Oceania. It also claims about of Antarctica under the Chilean Antarctic Territory. The country's capital and largest city is Santiago, and its national language is Spanish. Spain conquered and colonized the region in the mid-16th century, replacing Inca rule, but failing to conquer the independent Mapuche who inhabited what is now south-central Chile. In 1818, after declaring in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cepheid Variable
A Cepheid variable () is a type of star that pulsates radially, varying in both diameter and temperature and producing changes in brightness with a well-defined stable period and amplitude. A strong direct relationship between a Cepheid variable's luminosity and pulsation period established Cepheids as important indicators of cosmic benchmarks for scaling galactic and extragalactic distances. This robust characteristic of classical Cepheids was discovered in 1908 by Henrietta Swan Leavitt after studying thousands of variable stars in the Magellanic Clouds. This discovery allows one to know the true luminosity of a Cepheid by simply observing its pulsation period. This in turn allows one to determine the distance to the star, by comparing its known luminosity to its observed brightness. The term ''Cepheid'' originates from Delta Cephei in the constellation Cepheus, identified by John Goodricke in 1784, the first of its type to be so identified. The mechanics of stellar pu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bolometer
A bolometer is a device for measuring radiant heat by means of a material having a temperature-dependent electrical resistance. It was invented in 1878 by the American astronomer Samuel Pierpont Langley. Principle of operation A bolometer consists of an absorptive element, such as a thin layer of metal, connected to a thermal reservoir (a body of constant temperature) through a thermal link. The result is that any radiation impinging on the absorptive element raises its temperature above that of the reservoir – the greater the absorbed power, the higher the temperature. The intrinsic thermal time constant, which sets the speed of the detector, is equal to the ratio of the heat capacity of the absorptive element to the thermal conductance between the absorptive element and the reservoir. The temperature change can be measured directly with an attached resistive thermometer, or the resistance of the absorptive element itself can be used as a thermometer. Metal bolometers us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrheliometer
A pyrheliometer is an instrument for measurement of direct beam solar irradiance. Sunlight enters the instrument through a window and is directed onto a thermopile which converts heat to an electrical signal that can be recorded. The signal voltage is converted via a formula to measure watts per square metre. Standards Pyrheliometer measurement specifications are subject to International Organization for Standardization (ISO) and World Meteorological Organization (WMO) standards. Comparisons between pyrheliometers for intercalibration are carried out regularly to measure the amount of solar energy received. The aim of the International Pyrheliometer Comparisons, which take place every 5 years at the World Radiation Centre in Davos, is to ensure the world-wide transfer of the World Radiometric Reference. During this event, all participants bring their instruments, solar-tracking and data acquisition systems to Davos to conduct simultaneous solar radiation measurements with the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ångström
The angstromEntry "angstrom" in the Oxford online dictionary. Retrieved on 2019-03-02 from https://en.oxforddictionaries.com/definition/angstrom.Entry "angstrom" in the Merriam-Webster online dictionary. Retrieved on 2019-03-02 from https://www.merriam-webster.com/dictionary/angstrom. (, ; , ) or ångström is a metric unit of length equal to m; that is, one ten-billionth ( US) of a metre, a hundred-millionth of a centimetre,Entry "angstrom" in the Oxford English Dictionary, 2nd edition (1986). Retrieved on 2021-11-22 from https://www.oed.com/oed2/00008552. 0.1 nanometre, or 100 picometres. Its symbol is Å, a letter of the Swedish alphabet. The unit is named after the Swedish physicist Anders Jonas Ångström (1814–1874). The angstrom is often used in the natural sciences and technology to express sizes of atoms, molecules, microscopic biological structures, and lengths of chemical bonds, arrangement of atoms in crystals,Arturas Vailionis (2015):Geometry of Crystals Lect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spectrograph
An optical spectrometer (spectrophotometer, spectrograph or spectroscope) is an instrument used to measure properties of light over a specific portion of the electromagnetic spectrum, typically used in spectroscopic analysis to identify materials. The variable measured is most often the light's intensity but could also, for instance, be the polarization state. The independent variable is usually the wavelength of the light or a unit directly proportional to the photon energy, such as reciprocal centimeters or electron volts, which has a reciprocal relationship to wavelength. A spectrometer is used in spectroscopy for producing spectral lines and measuring their wavelengths and intensities. Spectrometers may operate over a wide range of non-optical wavelengths, from gamma rays and X-rays into the far infrared. If the instrument is designed to measure the spectrum on an absolute scale rather than a relative one, then it is typically called a spectrophotometer. The majority o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coelostat
A solar telescope is a special purpose telescope used to observe the Sun. Solar telescopes usually detect light with wavelengths in, or not far outside, the visible spectrum. Obsolete names for Sun telescopes include heliograph and photoheliograph. Professional solar telescopes Solar telescopes need optics large enough to achieve the best possible diffraction limit but less so for the associated light-collecting power of other astronomical telescopes. However, recently newer narrower filters and higher framerates have also driven solar telescopes towards photon-starved operations. Both the Daniel K. Inouye Solar Telescope as well as the proposed European Solar Telescope (EST) have larger apertures not only to increase the resolution, but also to increase the light-collecting power. Because solar telescopes operate during the day, seeing is generally worse than for night-time telescopes, because the ground around the telescope is heated which causes turbulence and degrades the res ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sinai Peninsula
The Sinai Peninsula, or simply Sinai (now usually ) (, , cop, Ⲥⲓⲛⲁ), is a peninsula in Egypt, and the only part of the country located in Asia. It is between the Mediterranean Sea to the north and the Red Sea to the south, and is a land bridge between Asia and Africa. Sinai has a land area of about (6 percent of Egypt's total area) and a population of approximately 600,000 people. Administratively, the vast majority of the area of the Sinai Peninsula is divided into two Governorates of Egypt, governorates: the South Sinai Governorate and the North Sinai Governorate. Three other governorates span the Suez Canal, crossing into African Egypt: Suez Governorate on the southern end of the Suez Canal, Ismailia Governorate in the center, and Port Said Governorate in the north. In the classical era the region was known as Arabia Petraea. The peninsula acquired the name Sinai in modern times due to the assumption that a mountain near Saint Catherine's Monastery is the Biblical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charles Greeley Abbot
Charles Greeley Abbot (May 31, 1872 – December 17, 1973) was an American astrophysicist and the fifth secretary of the Smithsonian Institution, serving from 1928 until 1944. Abbot went from being director of the Smithsonian Astrophysical Observatory, to becoming Assistant Secretary, and then Secretary of the Smithsonian Institution over the course of his career. As an astrophysicist, he researched the solar constant, research that led him to invent the solar cooker, solar boiler, solar still, and other patented solar energy inventions. Early life and education Charles Greeley Abbot was born in Wilton, New Hampshire. His parents, Harris Abbot and Caroline Ann Greeley, were farmers and he was the youngest of four children. As a youth he built and invented numerous things, such as a forge to fix tools, a water wheel to power a saw, and a bicycle. He dropped out of school when he was 13 to become a carpenter. Two years later he went back to high school. He attended Phillips Ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
California
California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territories of the United States by population, most populous U.S. state and the List of U.S. states and territories by area, 3rd largest by area. It is also the most populated Administrative division, subnational entity in North America and the 34th most populous in the world. The Greater Los Angeles area and the San Francisco Bay Area are the nation's second and fifth most populous Statistical area (United States), urban regions respectively, with the former having more than 18.7million residents and the latter having over 9.6million. Sacramento, California, Sacramento is the state's capital, while Los Angeles is the List of largest California cities by population, most populous city in the state and the List of United States cities by population, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
