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Khālid Ibn ʿAbd Al‐Malik Al‐Marwarrūdhī
Khālid ibn ʿAbd al‐Malik al‐Marwarrūdhī () was a 9th-century Baghdadi astronomer. In 827, Marwarrūdhī, together with the astronomer ʿAlī ibn ʿĪsā al-Asṭurlābī and a party of surveyors, measured the length of a meridian arc of one degree of latitude. The party travelled to the Nineveh Plains in the valley of the Tigris, at 35 degrees north latitude. The measurement they obtained enabled the astronomers to obtain a value of for the circumference of the Earth, (or, according to other sources, ). The two researchers measured in Arabian , and determined the geographical latitudes of the end points they used from the star altitudes in a celestial horizontal coordinate system. As it is thought that one Arabian represented , they found the length of 1° of meridian to be , which differs from the true value by . Marwarrūdhī was chosen by the geometer Al-Abbās ibn Said al-Jawharī to organize a new observatory on Mount Qasioun Mount Qasioun () is a moun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Islamic Golden Age
The Islamic Golden Age was a period of scientific, economic, and cultural flourishing in the history of Islam, traditionally dated from the 8th century to the 13th century. This period is traditionally understood to have begun during the reign of the Abbasid Caliphate, Abbasid caliph Harun al-Rashid (786 to 809) with the inauguration of the House of Wisdom, which saw Ulama, scholars from all over the Muslim world flock to Baghdad, the world's largest city at the time, to translate the known world's classical knowledge into Arabic and Persian language, Persian. The period is traditionally said to have ended with the collapse of the Abbasid caliphate due to Mongol invasions and conquests, Mongol invasions and the Siege of Baghdad (1258), Siege of Baghdad in 1258. There are a few alternative timelines. Some scholars extend the end date of the golden age to around 1350, including the Timurid Renaissance within it, while others place the end of the Islamic Golden Age as late as the en ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Circumference
In geometry, the circumference () is the perimeter of a circle or ellipse. The circumference is the arc length of the circle, as if it were opened up and straightened out to a line segment. More generally, the perimeter is the curve length around any closed figure. Circumference may also refer to the circle itself, that is, the Locus (geometry), locus corresponding to the Edge (geometry), edge of a Disk (geometry), disk. The is the circumference, or length, of any one of its great circles. Circle The circumference of a circle is the distance around it, but if, as in many elementary treatments, distance is defined in terms of straight lines, this cannot be used as a definition. Under these circumstances, the circumference of a circle may be defined as the Limit (mathematics), limit of the perimeters of inscribed regular polygons as the number of sides increases without bound. The term circumference is used when measuring physical objects, as well as when considering abstrac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geodesists
Geodesy or geodetics is the science of measuring and representing the geometry, gravity, and spatial orientation of the Earth in temporally varying 3D. It is called planetary geodesy when studying other astronomical bodies, such as planets or circumplanetary systems. Geodynamical phenomena, including crustal motion, tides, and polar motion, can be studied by designing global and national control networks, applying space geodesy and terrestrial geodetic techniques, and relying on datums and coordinate systems. Geodetic job titles include geodesist and geodetic surveyor. History Geodesy began in pre-scientific antiquity, so the very word geodesy comes from the Ancient Greek word or ''geodaisia'' (literally, "division of Earth"). Early ideas about the figure of the Earth held the Earth to be flat and the heavens a physical dome spanning over it. Two early arguments for a spherical Earth were that lunar eclipses appear to an observer as circular shadows and that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UNESCO
The United Nations Educational, Scientific and Cultural Organization (UNESCO ) is a List of specialized agencies of the United Nations, specialized agency of the United Nations (UN) with the aim of promoting world peace and International security, security through international cooperation in education, arts, sciences and culture. It has 194 Member states of UNESCO, member states and 12 associate members, as well as partners in the Non-governmental organization, non-governmental, Intergovernmental organization, intergovernmental and private sector. Headquartered in Paris, France, UNESCO has 53 regional field offices and 199 National Commissions for UNESCO, national commissions. UNESCO was founded in 1945 as the successor to the League of Nations' International Committee on Intellectual Cooperation.English summary). UNESCO's founding mission, which was shaped by the events of World War II, is to advance peace, sustainable development and human rights by facilitating collaboratio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mount Qasioun
Mount Qasioun () is a mountain overlooking the city of Damascus, Syria. It has a range of restaurants, from which the whole city can be viewed. Due to its high elevation, several communications and broadcasting networks constructed relay stations at the summit for the city's communications. As the city has expanded over the years, some districts have been established at the foot of the mountain. Its highest point is .Profile lib.utexas.edu. Accessed 8 April 2024. Etymology The term Qasioun might mean "hard and dry" in , which is the characteristic of the bare rocky mountain that has no grass, greenery, or water. History ...
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Observatory
An observatory is a location used for observing terrestrial, marine, or celestial events. Astronomy, climatology/meteorology, geophysics, oceanography and volcanology are examples of disciplines for which observatories have been constructed. The term ''observatoire'' has been used in French since at least 1976 to denote any institution that compiles and presents data on a particular subject (such as public health observatory) or for a particular geographic area (European Audiovisual Observatory). Astronomical observatories Astronomical observatories are mainly divided into four categories: space observatory, space-based, airborne observatory, airborne, ground-based, and underground-based. Historically, ground-based observatories were as simple as containing a mural instrument (for measuring the angle between stars) or Stonehenge (which has some alignments on astronomical phenomena). Ground-based observatories Ground-based observatories, located on the surface of Earth, are u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Al-Abbās Ibn Said Al-Jawharī
Al-ʿAbbās ibn Saʿid al-Jawharī (; ), known as Al-Jawhari, was a geometer who worked at the House of Wisdom in Baghdad and for in a short time in Damascus, where he made astronomical observations. Born (and probably dying) in Baghdad, he was probably of Iranian origin. His most important work was his commentary on ''Euclid's Elements'', which contained nearly 50 additional propositions and an attempted mathematical proof of the parallel postulate. Described as having superb knowledge of Greek, which was unusual for a Muslim scholar), Al-Jawhari is credited with a translation into Arabic of the Indian polymath A polymath or polyhistor is an individual whose knowledge spans many different subjects, known to draw on complex bodies of knowledge to solve specific problems. Polymaths often prefer a specific context in which to explain their knowledge, ... Shanaq al-Hindi's ''Book of Poisons''. References Sources * * Further reading * * PDF version * * 8 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horizontal Coordinate System
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] |
Altitude
Altitude is a distance measurement, usually in the vertical or "up" direction, between a reference datum (geodesy), datum and a point or object. The exact definition and reference datum varies according to the context (e.g., aviation, geometry, geographical survey, sport, or atmospheric pressure). Although the term ''altitude'' is commonly used to mean the height above sea level of a location, in geography the term elevation is often preferred for this usage. In aviation, altitude is typically measured relative to mean sea level or above ground level to ensure safe navigation and flight operations. In geometry and geographical surveys, altitude helps create accurate topographic maps and understand the terrain's elevation. For high-altitude trekking and sports, knowing and adapting to altitude is vital for performance and safety. Higher altitudes mean reduced oxygen levels, which can lead to altitude sickness if proper acclimatization measures are not taken. Vertical distance ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
35th Parallel North
Following are circles of latitude between the 30th parallel north and the 35th parallel north: 31st parallel north The 31st parallel north is a circle of latitude that is 31 degrees north of the Earth's equatorial plane. It crosses Africa, Asia, the Pacific Ocean, North America, and the Atlantic Ocean. At this latitude the sun is visible for 14 hours, 10 minutes during the summer solstice and 10 hours, 8 minutes during the winter solstice. Part of the border between Iran and Iraq is defined by the parallel. In the United States, it defines part of the border between the states of Mississippi and Louisiana, and most of the border between Alabama and Florida. Andrew Ellicott surveyed this parallel in 1797, which in Pinckney's Treaty two years before had been defined as the border between the United States and the Spanish territory of West Florida. Around the world Starting at the Prime Meridian and heading eastwards, the parallel 31° north passes through: : 32nd pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomy
Astronomy is a natural science that studies celestial objects and the phenomena that occur in the cosmos. It uses mathematics, physics, and chemistry in order to explain their origin and their overall evolution. Objects of interest include planets, natural satellite, moons, stars, nebulae, galaxy, galaxies, meteoroids, asteroids, and comets. Relevant phenomena include supernova explosions, gamma ray bursts, quasars, blazars, pulsars, and cosmic microwave background radiation. More generally, astronomy studies everything that originates beyond atmosphere of Earth, Earth's atmosphere. Cosmology is a branch of astronomy that studies the universe as a whole. Astronomy is one of the oldest natural sciences. The early civilizations in recorded history made methodical observations of the night sky. These include the Egyptian astronomy, Egyptians, Babylonian astronomy, Babylonians, Greek astronomy, Greeks, Indian astronomy, Indians, Chinese astronomy, Chinese, Maya civilization, M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
