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Southern African Large Telescope
The Southern African Large Telescope (SALT) is a 9.2-metre optical telescope designed mainly for spectroscopy. It consists of 91 hexagonal mirror segments each with a 1-metre inscribed diameter, resulting in a total hexagonal mirror of 11.1 by 9.8 m. However, its effective aperture is only 9.2 m. It is located close to the town of Sutherland in the semi-desert region of the Karoo, South Africa. It is a facility of the South African Astronomical Observatory, the national optical observatory of South Africa. SALT is the largest optical telescope in the southern hemisphere. It enables spectroscopic and polarimetric analysis and imaging of the radiation from astronomical objects that are out of reach of northern hemisphere telescopes. It is closely based on the Hobby–Eberly Telescope (HET) at McDonald Observatory, with some changes in its design, especially to the spherical aberration corrector. The main purpose for these changes was to improve the telescope's fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Encircled Energy
In optics, encircled energy is a measure of concentration of energy in an image, or projected laser at a given range. For example, if a single star is brought to its sharpest focus by a lens giving the smallest image possible with that given lens (called a point spread function or PSF), calculation of the encircled energy of the resulting image gives the distribution of energy in that PSF. Encircled energy is calculated by first determining the total energy of the PSF over the full image plane, then determining the centroid of the PSF. Circles of increasing radius are then created at that centroid and the PSF energy within each circle is calculated and divided by the total energy. As the circle increases in radius, more of the PSF energy is enclosed, until the circle is sufficiently large to completely contain all the PSF energy. The encircled energy curve thus ranges from zero to one. A typical criterion for encircled energy (EE) is the radius of the PSF at which either 50% ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Altitude (astronomy)
The horizontal coordinate system is a celestial coordinate system that uses the observer's local horizon as the fundamental plane to define two angles of a spherical coordinate system: altitude and ''azimuth''. Therefore, the horizontal coordinate system is sometimes called the az/el system, the alt/az system, or the alt-azimuth system, among others. In an altazimuth mount of a telescope, the instrument's two axes follow altitude and azimuth. Definition This celestial coordinate system divides the sky into two hemispheres: The upper hemisphere, where objects are above the horizon and are visible, and the lower hemisphere, where objects are below the horizon and cannot be seen, since the Earth obstructs views of them. The great circle separating the hemispheres is called the ''celestial horizon'', which is defined as the great circle on the celestial sphere whose plane is normal to the local gravity vector (the vertical direction). In practice, the horizon can be define ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poland
Poland, officially the Republic of Poland, is a country in Central Europe. It extends from the Baltic Sea in the north to the Sudetes and Carpathian Mountains in the south, bordered by Lithuania and Russia to the northeast, Belarus and Ukraine to the east, Slovakia and the Czech Republic to the south, and Germany to the west. The territory has a varied landscape, diverse ecosystems, and a temperate climate. Poland is composed of Voivodeships of Poland, sixteen voivodeships and is the fifth most populous member state of the European Union (EU), with over 38 million people, and the List of European countries by area, fifth largest EU country by area, covering . The capital and List of cities and towns in Poland, largest city is Warsaw; other major cities include Kraków, Wrocław, Łódź, Poznań, and Gdańsk. Prehistory and protohistory of Poland, Prehistoric human activity on Polish soil dates to the Lower Paleolithic, with continuous settlement since the end of the Last Gla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Germany
Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total population of over 84 million in an area of , making it the most populous member state of the European Union. It borders Denmark to the north, Poland and the Czech Republic to the east, Austria and Switzerland to the south, and France, Luxembourg, Belgium, and the Netherlands to the west. The Capital of Germany, nation's capital and List of cities in Germany by population, most populous city is Berlin and its main financial centre is Frankfurt; the largest urban area is the Ruhr. Settlement in the territory of modern Germany began in the Lower Paleolithic, with various tribes inhabiting it from the Neolithic onward, chiefly the Celts. Various Germanic peoples, Germanic tribes have inhabited the northern parts of modern Germany since classical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South African Department Of Science And Technology
The Department of Science and Innovation (DST; formerly the Department of Science and Technology) is the South African government department responsible for scientific research, including space programmes. The current Minister is Blade Nzimande. Much of the department's work is ultimately carried out through various quasi-independent agencies (although still usually government bodies) including: * the National Research Foundation, which receives a substantial proportion of the DST budget to carry out various research support tasks, including supporting key national research infrastructure ("National Research Facilities"), scientific research grant administration and a student grant scheme; * the Council for Scientific and Industrial Research, which acts as a quasi-privatised research and development agency with a specific focus on research of application to industry; * the Technology Innovation Agency, which serves to provide funding to turn innovative research into commercia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thabo Mbeki
Thabo Mvuyelwa Mbeki (; born 18 June 1942) is a South African politician who served as the 2nd democratic president of South Africa from 14 June 1999 to 24 September 2008, when he resigned at the request of his party, the African National Congress (ANC). Before that, he was Deputy President of South Africa, deputy president under Nelson Mandela from 1994 to 1999. The son of Govan Mbeki, an ANC intellectual, Mbeki has been involved in ANC politics since 1956, when he joined the African National Congress Youth League, ANC Youth League, and has been a member of the party's National Executive Committee of the African National Congress, National Executive Committee since 1975. Born in the Transkei, he left South Africa aged twenty to attend university in England, and spent almost three decades in exile abroad, until the ANC was unbanned in 1990. He rose through the organisation in its information and publicity section and as Oliver Tambo's protégé, but he was also an experienced d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
President Of South Africa
The president of South Africa is the head of state and head of government of the Republic of South Africa. The president directs the executive branch of the government and is the commander-in-chief of the South African National Defence Force. Between 1961 and 1994, the office of head of state was the state presidency. The president is elected by the National Assembly, the lower house of Parliament, and is usually the leader of the largest party, which has been the African National Congress since the first multiracial election was held on 27 April 1994. The Constitution limits the president's time in office to two five-year terms. The first president to be elected under the new constitution was Nelson Mandela. The incumbent is Cyril Ramaphosa, who was elected by the National Assembly on 15 February 2018 following the resignation of Jacob Zuma. Under the interim constitution (valid from 1994–96), there was a Government of National Unity, in which a member of Parliament ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lagoon Nebula
The Lagoon Nebula (catalogued as Messier 8 or M8, NGC 6523, Sharpless 25, RCW 146, and Gum 72) is a giant interstellar cloud in the constellation Sagittarius. It is classified as an emission nebula and has an H II region. The Lagoon Nebula was discovered by Giovanni Hodierna in 1654 and is one of only two star-forming nebulae faintly visible to the eye from mid-northern latitudes. Seen with binoculars, it appears as a distinct cloud-like patch with a definite core. Within the nebula is the open cluster NGC 6530. Characteristics The Lagoon Nebula is estimated to be between 4,000–6,000 light-years away from the Earth. In the sky of Earth, it spans 90' by 40', which translates to an actual dimension of 110 by 50 light years. Like many nebulae, it appears pink in time-exposure color photos but is gray to the eye peering through binoculars or a telescope, human vision having poor color sensitivity at low light levels. The nebula contains a number of Bok globules (dark, colla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC 6744
__NOTOC__ NGC 6744 (also known as Caldwell 101 or the Pavo Galaxy) is an intermediate spiral galaxy in the constellation Pavo (Peacock). Its velocity with respect to the cosmic microwave background is 802 ± 3km/s, which corresponds to a Hubble distance of . However, 21 ''non redshift'' measurements give a distance of . It was discovered on 30 June 1826 by Scottish astronomer James Dunlop, observing from Parramatta, Australia. One of the largest spiral galaxies in the local universe, NGC 6744 is considered a Milky Way mimic in the immediate vicinity, displaying remarkable star formation, flocculent (fluffy) arms, and an elongated core. It has at least one distorted companion galaxy (NGC 6744A) superficially similar to one of the Magellanic Clouds. NGC6744 is a LINER galaxy, i.e., its nucleus has an emission spectrum characterized by broad lines of weakly ionized atoms. The galaxy has an active galactic nucleus (AGN) of low luminosity. NGC 6744 lies within the Virgo Supercl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spiral Galaxy
Spiral galaxies form a galaxy morphological classification, class of galaxy originally described by Edwin Hubble in his 1936 work ''The Realm of the Nebulae''Alt URL pp. 124–151) and, as such, form part of the Hubble sequence. Most spiral galaxies consist of a flat, rotating Disc (galaxy), disk containing stars, Interstellar medium, gas and dust, and a central concentration of stars known as the Bulge (astronomy), bulge. These are often surrounded by a much fainter Galactic halo, halo of stars, many of which reside in globular clusters. Spiral galaxies are named by their spiral structures that extend from the center into the galactic disc. The spiral arms are sites of ongoing star formation and are brighter than the surrounding disc because of the young, hot OB stars that inhabit them. Roughly two-thirds of all spirals are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC 6152
NGC 6152 is an open cluster of stars located in the constellation Norma. It was discovered by John Herschel Sir John Frederick William Herschel, 1st Baronet (; 7 March 1792 – 11 May 1871) was an English polymath active as a mathematician, astronomer, chemist, inventor and experimental photographer who invented the blueprint and did botanical work. ... in 1834. References External links * 6152 Open clusters Norma (constellation) {{star-cluster-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Open Cluster
An open cluster is a type of star cluster made of tens to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. More than 1,100 open clusters have been discovered within the Milky Way galaxy, and many more are thought to exist. Each one is loosely bound by mutual gravity, gravitational attraction and becomes disrupted by close encounters with other clusters and clouds of gas as they orbit the Galactic Center. This can result in a loss of cluster members through internal close encounters and a dispersion into the main body of the galaxy. Open clusters generally survive for a few hundred million years, with the most massive ones surviving for a few billion years. In contrast, the more massive globular clusters of stars exert a stronger gravitational attraction on their members, and can survive for longer. Open clusters have been found only in spiral galaxy, spiral and irregular galaxy, irregular galaxies, in which active star formatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
