1.
Cosmolabe
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The cosmolabe was an ancient astronomical instrument resembling the astrolabe, formerly used for measuring the angles between heavenly bodies. Jacques Besson also uses this name, or universal instrument, for his invention described in Le cosmolabe, which could be used for astrometry, cartography, navigation and this article incorporates text from a work in the public domain, Porter, Noah, ed. Websters entry needed. Springfield, Massachusetts, C. & G. Merriam Co and this article incorporates text from a publication now in the public domain, Chambers, Ephraim, ed. article name needed. Cyclopædia, or an Universal Dictionary of Arts and Sciences, james and John Knapton, et al
2.
French ship Astrolabe
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Dictionnaire des bâtiments de la flotte de guerre française de Colbert à nos jours. Dictionnaire des bâtiments de la flotte de guerre française de Colbert à nos jours
3.
Tabriz
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Tabriz is the most populated city in the Iranian Azerbaijan, one of the historical capitals of Iran, and the present capital of East Azerbaijan Province. Located in the Quru River valley between the ridge of the volcanic cones of the Sahand and Eynali mountains, Tabrizs elevation ranges between 1,350 and 1,600 metres above sea level. The valley opens up into a plain that slopes down to the eastern shores of Lake Urmia,60 kilometres to the west. With cold winters and temperate summers, the city is considered a summer resort, Tabriz is named Worlds Carpet and Crafts City, it is also appointed as the exemplary tourism city in 2018 by Organisation of Islamic Cooperation. With a population of 1.6 million, Tabriz is the biggest economic hub, the population consists mostly of Iranian Azerbaijanis and the most spoken language in the city is Azeri Turkish. Tabriz is a heavy industry hub for automobile, machine tools, refineries and petrochemical, textile. The city is famous for its handicrafts including hand-woven rugs and jewelry, local confectioneries, chocolates, dried nuts, and traditional food of Tabriz are recognized all around Iran as some of the best Iranian food. Tabriz is also a hub and a site for some of the most prestigious cultural institutes in the northwest of Iran. The city contains many historical monuments representing the transition of Iranian architecture in its long historical timelines. Most of the historical sites in the city belong to Ilkhanid, Safavid. From the early era, the city was pivotal in the development, movement. From the 19th century, it became the most important city in the country in numerous respects, as the closest Iranian hub to Europe, many aspects of the early modern modernisation in Iran started in Tabriz. During almost the entire Qajar period, it functioned as the seat for the prince as well. According to some sources, including Encyclopædia Britannica, the name Tabriz derives from tap-riz, in AD297, it became the capital of Tiridates III, king of Armenia. However, this story has an origin and no ancient source has recorded such event. This is based on accounts of Vardan, the Armenian historian in 13th century, the early history of Tabriz is not well-documented. The earliest inscription about Tabriz, referring to the city as Tarui or Tauris, is on the Assyrian King Sargon IIs epigraph in 714 BC, Tabriz has been chosen as the capital for some rulers commencing from Atropates era and his dynasty. A recent excavation at the site of the Iron Age museum, in the north of the Blue Mosque site, more likely the city has been destroyed multiple times either by natural disasters or by the invading armies
4.
Astronomy in the medieval Islamic world
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Islamic astronomy comprises the astronomical developments made in the Islamic world, particularly during the Islamic Golden Age, and mostly written in the Arabic language. These developments mostly took place in the Middle East, Central Asia, Al-Andalus, and North Africa and these included Greek, Sassanid, and Indian works in particular, which were translated and built upon. Islamic astronomy also had an influence on Chinese astronomy and Malian astronomy, a significant number of stars in the sky, such as Aldebaran, Altair and Deneb, and astronomical terms such as alidade, azimuth, and nadir, are still referred to by their Arabic names. A large corpus of literature from Islamic astronomy remains today, numbering approximately 10,000 manuscripts scattered throughout the world, even so, a reasonably accurate picture of Islamic activity in the field of astronomy can be reconstructed. These observations were based on the rising and setting of stars. Anwa continued to be developed after Islamization by the Arabs, where Islamic astronomers added mathematical methods to their empirical observations, according to David King, after the rise of Islam, the religious obligation to determine the qibla and prayer times inspired more progress in astronomy for centuries. The first astronomical texts that were translated into Arabic were of Indian and Persian origin, another text translated was the Zij al-Shah, a collection of astronomical tables compiled in Sasanid Persia over two centuries. Fragments of texts during this period indicate that Arabs adopted the function in place of the chords of arc used in Greek trigonometry. The House of Wisdom was an established in Baghdad under Abbasid caliph Al-Mamun in the early 9th century. From this time, independent investigation into the Ptolemaic system became possible, Astronomical research was greatly supported by the Abbasid caliph al-Mamun through The House of Wisdom. Baghdad and Damascus became the centers of such activity, the caliphs not only supported this work financially, but endowed the work with formal prestige. The first major Muslim work of astronomy was Zij al-Sindh by al-Khwarizmi in 830, the work contains tables for the movements of the sun, the moon and the five planets known at the time. The work is significant as it introduced Ptolemaic concepts into Islamic sciences and this work also marks the turning point in Islamic astronomy. Hitherto, Muslim astronomers had adopted a primarily research approach to the field, translating works of others, al-Khwarizmis work marked the beginning of nontraditional methods of study and calculations. In 850, al-Farghani wrote Kitab fi Jawani, the book primarily gave a summary of Ptolemic cosmography. However, it also corrected Ptolemy based on findings of earlier Arab astronomers, al-Farghani gave revised values for the obliquity of the ecliptic, the precessional movement of the apogees of the sun and the moon, and the circumference of the earth. The book was circulated through the Muslim world, and even translated into Latin. The period when a distinctive Islamic system of astronomy flourished, the period began as the Muslim astronomers began questioning the framework of the Ptolemaic system of astronomy
5.
Museum of the History of Science, Oxford
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The Museum of the History of Science in Broad Street, Oxford, England, holds a leading collection of scientific instruments from Middle Ages to the 19th century. The museum building is known as the Old Ashmolean Building to distinguish it from the newer Ashmolean Museum building completed in 1894. The museum was built in 1683, and it is the worlds oldest surviving purpose-built museum, the museum is open to the general public with free admission every afternoon except Mondays. Built in 1683 to house Elias Ashmoles collection, it was the worlds first purpose-built museum building and was open to the public. The collection and the building now occupies a special position in the study of the history of science and in the development of western culture. J. Bowen and Gavin de Beer, the museum shows the development of mechanical clocks. Lantern clocks and longcase clocks are exhibited in the Beeson Room, early turret clocks are exhibited above the stairs from the basement to the raised ground floor. From October 2009 until February 2010, the Museum hosted the first major exhibition of Steampunk art objects, curated by Art Donovan and presented by Dr Jim Bennett, then the museum director. The following have been Curator or Secretary to the Committee or Director at the museum, R. T. Gunther F. Sherwood Taylor C. H. Josten F. R. Maddison J
6.
Canterbury Astrolabe Quadrant
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The Canterbury Astrolabe Quadrant is the only one of its kind definitely made in England. Astrolabes are calculation instruments that enable their users to tell the time and determine their geographical latitude using the position of the sun and stars. An extremely rare instrument, the Canterbury Astrolabe Quadrant probably belonged to a scholar who may have lost it in Canterbury while on pilgrimage to that city. It is also the first astrolabe to have found during an archaeological dig. Scientific instruments such as this are usually handed down generation to generation or found among family possessions. The British Museum eventually purchased it in 2008 with £175,000 from The British Museum Friends plus grants of £125,000 from the National Heritage Memorial Fund and £50,000 from The Art Fund. Andrew Burnett, Deputy Director of the British Museum, said, the Astrolabe on Curator & Collector
7.
Ruler
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A ruler, sometimes called a rule or line gauge, is an instrument used in geometry, technical drawing, printing, engineering and building to measure distances or to rule straight lines. The ruler is a straightedge which may also contain calibrated lines to measure distances, rulers have long been made from different materials and in a wide range of sizes. Plastics have also used since they were invented, they can be molded with length markings instead of being scribed. Metal is used for more durable rulers for use in the workshop,12 inches or 30 cm in length is useful for a ruler to be kept on a desk to help in drawing. Shorter rulers are convenient for keeping in a pocket, longer rulers, e. g.18 inches are necessary in some cases. Rigid wooden or plastic yardsticks,1 yard long, and meter sticks,1 meter long, are also used, classically, long measuring rods were used for larger projects, now superseded by tape measure or laser rangefinders. Desk rulers are used for three purposes, to measure, to aid in drawing straight lines and as a straight guide for cutting and scoring with a blade. Practical rulers have distance markings along their edges, a line gauge is a type of ruler used in the printing industry. These may be made from a variety of materials, typically metal or clear plastic, units of measurement on a basic line gauge usually include inches, agate, picas, and points. More detailed line gauges may contain sample widths of lines, samples of common type in several point sizes, measuring instruments similar in function to rulers are made portable by folding or retracting into a coil when not in use. When extended for use, they are straight, like a ruler, the illustrations on this page show a 2-meter carpenters rule, which folds down to a length of 24 cm to easily fit in a pocket, and a 5-meter-long tape, which retracts into a small housing. A flexible length measuring instrument which is not necessarily straight in use is the tailors fabric tape measure and it is used to measure around a solid body, e. g. a persons waist measurement, as well as linear measurement, e. g. inside leg. It is rolled up when not in use, taking up little space, a contraction rule is made having larger divisions than standard measures to allow for shrinkage of a metal casting. They may also be known as a shrinkage or shrink rule, a ruler software program can be used to measure pixels on a computer screen or mobile phone. These programs are known as screen rulers. In geometry, a ruler without any marks on it may be used only for drawing lines between points. A straightedge is used to help draw accurate graphs and tables. A ruler and compass construction refers to using an unmarked ruler
8.
Greek language
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Greek is an independent branch of the Indo-European family of languages, native to Greece and other parts of the Eastern Mediterranean. It has the longest documented history of any living language, spanning 34 centuries of written records and its writing system has been the Greek alphabet for the major part of its history, other systems, such as Linear B and the Cypriot syllabary, were used previously. The alphabet arose from the Phoenician script and was in turn the basis of the Latin, Cyrillic, Armenian, Coptic, Gothic and many other writing systems. Together with the Latin texts and traditions of the Roman world, during antiquity, Greek was a widely spoken lingua franca in the Mediterranean world and many places beyond. It would eventually become the official parlance of the Byzantine Empire, the language is spoken by at least 13.2 million people today in Greece, Cyprus, Italy, Albania, Turkey, and the Greek diaspora. Greek roots are used to coin new words for other languages, Greek. Greek has been spoken in the Balkan peninsula since around the 3rd millennium BC, the earliest written evidence is a Linear B clay tablet found in Messenia that dates to between 1450 and 1350 BC, making Greek the worlds oldest recorded living language. Among the Indo-European languages, its date of earliest written attestation is matched only by the now extinct Anatolian languages, the Greek language is conventionally divided into the following periods, Proto-Greek, the unrecorded but assumed last ancestor of all known varieties of Greek. The unity of Proto-Greek would have ended as Hellenic migrants entered the Greek peninsula sometime in the Neolithic era or the Bronze Age, Mycenaean Greek, the language of the Mycenaean civilisation. It is recorded in the Linear B script on tablets dating from the 15th century BC onwards, Ancient Greek, in its various dialects, the language of the Archaic and Classical periods of the ancient Greek civilisation. It was widely known throughout the Roman Empire, after the Roman conquest of Greece, an unofficial bilingualism of Greek and Latin was established in the city of Rome and Koine Greek became a first or second language in the Roman Empire. The origin of Christianity can also be traced through Koine Greek, Medieval Greek, also known as Byzantine Greek, the continuation of Koine Greek in Byzantine Greece, up to the demise of the Byzantine Empire in the 15th century. Much of the written Greek that was used as the language of the Byzantine Empire was an eclectic middle-ground variety based on the tradition of written Koine. Modern Greek, Stemming from Medieval Greek, Modern Greek usages can be traced in the Byzantine period and it is the language used by the modern Greeks, and, apart from Standard Modern Greek, there are several dialects of it. In the modern era, the Greek language entered a state of diglossia, the historical unity and continuing identity between the various stages of the Greek language is often emphasised. Greek speakers today still tend to regard literary works of ancient Greek as part of their own rather than a foreign language and it is also often stated that the historical changes have been relatively slight compared with some other languages. According to one estimation, Homeric Greek is probably closer to demotic than 12-century Middle English is to modern spoken English, Greek is spoken by about 13 million people, mainly in Greece, Albania and Cyprus, but also worldwide by the large Greek diaspora. Greek is the language of Greece, where it is spoken by almost the entire population
9.
Arabic
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Arabic is a Central Semitic language that was first spoken in Iron Age northwestern Arabia and is now the lingua franca of the Arab world. Arabic is also the language of 1.7 billion Muslims. It is one of six languages of the United Nations. The modern written language is derived from the language of the Quran and it is widely taught in schools and universities, and is used to varying degrees in workplaces, government, and the media. The two formal varieties are grouped together as Literary Arabic, which is the language of 26 states. Modern Standard Arabic largely follows the standards of Quranic Arabic. Much of the new vocabulary is used to denote concepts that have arisen in the post-Quranic era, Arabic has influenced many languages around the globe throughout its history. During the Middle Ages, Literary Arabic was a vehicle of culture in Europe, especially in science, mathematics. As a result, many European languages have borrowed many words from it. Many words of Arabic origin are found in ancient languages like Latin. Balkan languages, including Greek, have acquired a significant number of Arabic words through contact with Ottoman Turkish. Arabic has also borrowed words from languages including Greek and Persian in medieval times. Arabic is a Central Semitic language, closely related to the Northwest Semitic languages, the Ancient South Arabian languages, the Semitic languages changed a great deal between Proto-Semitic and the establishment of the Central Semitic languages, particularly in grammar. Innovations of the Central Semitic languages—all maintained in Arabic—include, The conversion of the suffix-conjugated stative formation into a past tense, the conversion of the prefix-conjugated preterite-tense formation into a present tense. The elimination of other prefix-conjugated mood/aspect forms in favor of new moods formed by endings attached to the prefix-conjugation forms, the development of an internal passive. These features are evidence of descent from a hypothetical ancestor. In the southwest, various Central Semitic languages both belonging to and outside of the Ancient South Arabian family were spoken and it is also believed that the ancestors of the Modern South Arabian languages were also spoken in southern Arabia at this time. To the north, in the oases of northern Hijaz, Dadanitic and Taymanitic held some prestige as inscriptional languages, in Najd and parts of western Arabia, a language known to scholars as Thamudic C is attested
10.
Persian language
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Persian, also known by its endonym Farsi, is one of the Western Iranian languages within the Indo-Iranian branch of the Indo-European language family. It is primarily spoken in Iran, Afghanistan, and Tajikistan and it is mostly written in the Persian alphabet, a modified variant of the Arabic script. Its grammar is similar to that of many contemporary European languages, Persian gets its name from its origin at the capital of the Achaemenid Empire, Persis, hence the name Persian. A Persian-speaking person may be referred to as Persophone, there are approximately 110 million Persian speakers worldwide, with the language holding official status in Iran, Afghanistan, and Tajikistan. For centuries, Persian has also been a cultural language in other regions of Western Asia, Central Asia. It also exerted influence on Arabic, particularly Bahrani Arabic. Persian is one of the Western Iranian languages within the Indo-European family, other Western Iranian languages are the Kurdish languages, Gilaki, Mazanderani, Talysh, and Balochi. Persian is classified as a member of the Southwestern subgroup within Western Iranian along with Lari, Kumzari, in Persian, the language is known by several names, Western Persian, Parsi or Farsi has been the name used by all native speakers until the 20th century. Since the latter decades of the 20th century, for reasons, in English. Tajiki is the variety of Persian spoken in Tajikistan and Uzbekistan by the Tajiks, according to the Oxford English Dictionary, the term Persian as a language name is first attested in English in the mid-16th century. Native Iranian Persian speakers call it Fārsi, Farsi is the Arabicized form of Pārsi, subsequent to Muslim conquest of Persia, due to a lack of the phoneme /p/ in Standard Arabic. The origin of the name Farsi and the place of origin of the language which is Fars Province is the Arabicized form of Pārs, in English, this language has historically been known as Persian, though Farsi has also gained some currency. Farsi is encountered in some literature as a name for the language. In modern English the word Farsi refers to the language while Parsi describes Zoroastrians, some Persian language scholars such as Ehsan Yarshater, editor of Encyclopædia Iranica, and University of Arizona professor Kamran Talattof, have also rejected the usage of Farsi in their articles. The international language-encoding standard ISO 639-1 uses the code fa, as its system is mostly based on the local names. The more detailed standard ISO 639-3 uses the name Persian for the dialect continuum spoken across Iran and Afghanistan and this consists of the individual languages Dari and Iranian Persian. Currently, Voice of America, BBC World Service, Deutsche Welle, Radio Free Europe/Radio Liberty also includes a Tajik service and an Afghan service. This is also the case for the American Association of Teachers of Persian, The Centre for Promotion of Persian Language and Literature, Persian is an Iranian language belonging to the Indo-Iranian branch of the Indo-European family of languages
11.
Inclinometer
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A clinometer or inclinometer is an instrument for measuring angles of slope, elevation or depression of an object with respect to gravity. It is also known as a meter, tilt indicator, slope alert, slope gauge, gradient meter, gradiometer, level gauge, level meter, declinometer. Clinometers measure both inclines and declines using three different units of measure, degrees, percent, and topo, astrolabes are inclinometers that were used for navigation and locating astronomical objects from ancient times to the Renaissance. In aircraft, the ball in turn coordinators or turn and bank indicators is sometimes referred to as an inclinometer. Inclinometers include examples such as Wells in-clinometer, the parts of which are a flat side, or base, on which it stands. The glass face of the disk is surrounded by a scale that marks the angle at which the surface of the liquid stands. A forester using a clinometer makes use of basic trigonometry, first the observer measures a straight-line distance D from some observation point O to the object. Then, using the clinometer, the measures the angle a between O and the top of the object. Then the observer does the same for the angle b between O and the bottom of the object, multiplying D by the tangent of a gives the height of the object above the observer, and by the tangent of b the depth of the object below the observer. Adding the two of course gives the height of the object. The forester stands at a distance from the base of the tree. The most common distances in the United States are 50 feet and 66 feet, to obtain accurate readings it is best to use taped measured distance instead of paced distances. For the most accurate readings it is best to use a distance that is not less than the height of the tree being measured, that is, the observer sights to the top of tree, if total height is the desired measurement. If the desired measurement is merchantable height—that is, the height producing timber that can be sold—the observer sights to a point on the tree above which no more merchantable timber is found, note that the observer should use slopes expressed as a percent. The observer then measures to the bottom of the tree, again using percents, the observer than takes the slope to the top of the tree, and subtracts the slope of the bottom of the tree from it. Note that when the ground slopes downwards, the observer will record a negative slope to the base of the tree, when this is subtracted from the slope to the top of the tree, it is actually being added. These numbers are divided by 100, and multiplied by the distance from the tree. There is still some error in this number, because the distance is measured along the ground, by standing at the base of the tree, the observer should mark his/her eye level
12.
Astronomy
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Astronomy is a natural science that studies celestial objects and phenomena. It applies mathematics, physics, and chemistry, in an effort to explain the origin of those objects and phenomena and their evolution. Objects of interest include planets, moons, stars, galaxies, and comets, while the phenomena include supernovae explosions, gamma ray bursts, more generally, all astronomical phenomena that originate outside Earths atmosphere are within the purview of astronomy. A related but distinct subject, physical cosmology, is concerned with the study of the Universe as a whole, Astronomy is the oldest of the natural sciences. The early civilizations in recorded history, such as the Babylonians, Greeks, Indians, Egyptians, Nubians, Iranians, Chinese, during the 20th century, the field of professional astronomy split into observational and theoretical branches. Observational astronomy is focused on acquiring data from observations of astronomical objects, theoretical astronomy is oriented toward the development of computer or analytical models to describe astronomical objects and phenomena. The two fields complement each other, with theoretical astronomy seeking to explain the results and observations being used to confirm theoretical results. Astronomy is one of the few sciences where amateurs can play an active role, especially in the discovery. Amateur astronomers have made and contributed to many important astronomical discoveries, Astronomy means law of the stars. Astronomy should not be confused with astrology, the system which claims that human affairs are correlated with the positions of celestial objects. Although the two share a common origin, they are now entirely distinct. Generally, either the term astronomy or astrophysics may be used to refer to this subject, however, since most modern astronomical research deals with subjects related to physics, modern astronomy could actually be called astrophysics. Few fields, such as astrometry, are purely astronomy rather than also astrophysics, some titles of the leading scientific journals in this field includeThe Astronomical Journal, The Astrophysical Journal and Astronomy and Astrophysics. In early times, astronomy only comprised the observation and predictions of the motions of objects visible to the naked eye, in some locations, early cultures assembled massive artifacts that possibly had some astronomical purpose. Before tools such as the telescope were invented, early study of the stars was conducted using the naked eye, most of early astronomy actually consisted of mapping the positions of the stars and planets, a science now referred to as astrometry. From these observations, early ideas about the motions of the planets were formed, and the nature of the Sun, Moon, the Earth was believed to be the center of the Universe with the Sun, the Moon and the stars rotating around it. This is known as the model of the Universe, or the Ptolemaic system. The Babylonians discovered that lunar eclipses recurred in a cycle known as a saros
13.
Navigators
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A navigator is the person on board a ship or aircraft responsible for its navigation. The navigators primary responsibility is to be aware of ship or aircraft position at all times, responsibilities include planning the journey, advising the ships captain or aircraft commander of estimated timing to destinations while en route, and ensuring hazards are avoided. U. S. Coast Guard officers that are shipboard navigators are normally cutter qualified at an analogous to the USN officers previously mentioned. Quartermasters are the navigators enlisted assistants and perform most of the technical navigation duties, aboard ships in the Merchant Marine and Merchant Navy, the second mate is generally the navigator. Navigators are sometimes called air navigators or flight navigators. Modern electronic navigation systems made the civil aviation navigators redundant by the early 1980s, in military aviation, navigators are still actively trained and licensed in some present day air forces, as electronic navigation aids cannot be assumed to be operational during wartime. In the worlds air forces, modern navigators are frequently tasked with weapon systems employment and co-pilot type duties depending on the type, model, a naval ships navigator is responsible for buying and maintaining its nautical charts. A nautical chart, or simply chart, is a representation of a maritime or flight region. Nautical charts are essential tools for marine navigation, many countries require vessels, especially commercial ships, Nautical charting may take the form of charts printed on paper or computerised electronic navigational charts. The nature of a waterway depicted by a chart changes regularly, every producer of navigational charts also provides a system to inform mariners and aviators of changes that affect the chart. Radio broadcasts give advance notice of urgent corrections, a convenient way to keep track of corrections is with a chart and publication correction record card system. When the time comes to use the chart, he pulls the chart and charts card and this system ensures that every chart is properly corrected prior to use. British merchant vessels receive weekly Notices to Mariners issued by the Admiralty, when corrections are received all charts are corrected in the ships folio and recorded in NP133A. This system ensures that all charts are corrected and up to date, in a deep sea vessel with a folio of over three thousand charts this can be a laborious and time-consuming task for the. Various and diverse methods exist for the correction of electronic navigational charts, the nature of waterways described by any given nautical publication changes regularly, and a mariner navigating by use of an old or uncorrected publication is courting disaster. Every producer of nautical publications also provides a system to inform mariners of changes that affect the chart, radio broadcasts give advance notice of urgent corrections. For ensuring that all publications are fully up-to-date, similar methods are employed as for nautical charts, various and diverse methods exist for the correction of electronic nautical publications. The navigator focuses on creating the ships passage plans, before each voyage begins, the navigator should develop a detailed mental model of how the entire voyage will proceed
14.
Orbital inclination
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Orbital inclination measures the tilt of an objects orbit around a celestial body. It is expressed as the angle between a plane and the orbital plane or axis of direction of the orbiting object. For a satellite orbiting the Earth directly above the equator, the plane of the orbit is the same as the Earths equatorial plane. The general case is that the orbit is tilted, it spends half an orbit over the northern hemisphere. If the orbit swung between 20° north latitude and 20° south latitude, then its orbital inclination would be 20°, the inclination is one of the six orbital elements describing the shape and orientation of a celestial orbit. It is the angle between the plane and the plane of reference, normally stated in degrees. For a satellite orbiting a planet, the plane of reference is usually the plane containing the planets equator, for planets in the Solar System, the plane of reference is usually the ecliptic, the plane in which the Earth orbits the Sun. This reference plane is most practical for Earth-based observers, therefore, Earths inclination is, by definition, zero. Inclination could instead be measured with respect to another plane, such as the Suns equator or the invariable plane, the inclination of orbits of natural or artificial satellites is measured relative to the equatorial plane of the body they orbit, if they orbit sufficiently closely. The equatorial plane is the perpendicular to the axis of rotation of the central body. An inclination of 30° could also be described using an angle of 150°, the convention is that the normal orbit is prograde, an orbit in the same direction as the planet rotates. Inclinations greater than 90° describe retrograde orbits, thus, An inclination of 0° means the orbiting body has a prograde orbit in the planets equatorial plane. An inclination greater than 0° and less than 90° also describe prograde orbits, an inclination of 63. 4° is often called a critical inclination, when describing artificial satellites orbiting the Earth, because they have zero apogee drift. An inclination of exactly 90° is an orbit, in which the spacecraft passes over the north and south poles of the planet. An inclination greater than 90° and less than 180° is a retrograde orbit, an inclination of exactly 180° is a retrograde equatorial orbit. For gas giants, the orbits of moons tend to be aligned with the giant planets equator, the inclination of exoplanets or members of multiple stars is the angle of the plane of the orbit relative to the plane perpendicular to the line-of-sight from Earth to the object. An inclination of 0° is an orbit, meaning the plane of its orbit is parallel to the sky. An inclination of 90° is an orbit, meaning the plane of its orbit is perpendicular to the sky
15.
Astronomical object
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An astronomical object or celestial object is a naturally occurring physical entity, association, or structure that current astronomy has demonstrated to exist in the observable universe. In astronomy, the object and body are often used interchangeably. Examples for astronomical objects include planetary systems, star clusters, nebulae and galaxies, while asteroids, moons, planets, and stars are astronomical bodies. A comet may be identified as both body and object, It is a body when referring to the nucleus of ice and dust. The universe can be viewed as having a hierarchical structure, at the largest scales, the fundamental component of assembly is the galaxy. Galaxies are organized groups and clusters, often within larger superclusters. Disc galaxies encompass lenticular and spiral galaxies with features, such as spiral arms, at the core, most galaxies have a supermassive black hole, which may result in an active galactic nucleus. Galaxies can also have satellites in the form of dwarf galaxies, the constituents of a galaxy are formed out of gaseous matter that assembles through gravitational self-attraction in a hierarchical manner. At this level, the fundamental components are the stars. The great variety of forms are determined almost entirely by the mass, composition. Stars may be found in systems that orbit about each other in a hierarchical organization. A planetary system and various objects such as asteroids, comets and debris. The various distinctive types of stars are shown by the Hertzsprung–Russell diagram —a plot of stellar luminosity versus surface temperature. Each star follows a track across this diagram. If this track takes the star through a region containing a variable type. An example of this is the instability strip, a region of the H-R diagram that includes Delta Scuti, RR Lyrae, the table below lists the general categories of bodies and objects by their location or structure. International Astronomical Naming Commission List of light sources List of Solar System objects Lists of astronomical objects SkyChart, Sky & Telescope Monthly skymaps for every location on Earth
16.
Triangulation
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In trigonometry and geometry, triangulation is the process of determining the location of a point by forming triangles to it from known points. Optical 3D measuring systems use this principle as well in order to determine the spatial dimensions, basically, the configuration consists of two sensors observing the item. One of the sensors is typically a digital device. The projection centers of the sensors and the point on the object’s surface define a triangle. Within this triangle, the distance between the sensors is the base b and must be known, by determining the angles between the projection rays of the sensors and the basis, the intersection point, and thus the 3D coordinate, is calculated from the triangular relations. Triangulation today is used for many purposes, including surveying, navigation, metrology, astrometry, binocular vision, model rocketry, the use of triangles to estimate distances dates to antiquity. He measured the length of the shadows and that of his own at the same moment. Such techniques would have been familiar to the ancient Egyptians. Problem 57 of the Rhind papyrus, a thousand years earlier, defines the seqt or seked as the ratio of the run to the rise of a slope, i. e. the reciprocal of gradients as measured today. The slopes and angles were measured using a rod that the Greeks called a dioptra
17.
Classical antiquity
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It is the period in which Greek and Roman society flourished and wielded great influence throughout Europe, North Africa and Southwestern Asia. Conventionally, it is taken to begin with the earliest-recorded Epic Greek poetry of Homer, and continues through the emergence of Christianity and it ends with the dissolution of classical culture at the close of Late Antiquity, blending into the Early Middle Ages. Such a wide sampling of history and territory covers many disparate cultures, Classical antiquity may refer also to an idealised vision among later people of what was, in Edgar Allan Poes words, the glory that was Greece, and the grandeur that was Rome. The culture of the ancient Greeks, together with influences from the ancient Near East, was the basis of art, philosophy, society. The earliest period of classical antiquity takes place before the background of gradual re-appearance of historical sources following the Bronze Age collapse, the 8th and 7th centuries BC are still largely proto-historical, with the earliest Greek alphabetic inscriptions appearing in the first half of the 8th century. Homer is usually assumed to have lived in the 8th or 7th century BC, in the same period falls the traditional date for the establishment of the Ancient Olympic Games, in 776 BC. The Phoenicians originally expanded from Canaan ports, by the 8th century dominating trade in the Mediterranean, carthage was founded in 814 BC, and the Carthaginians by 700 BC had firmly established strongholds in Sicily, Italy and Sardinia, which created conflicts of interest with Etruria. The Etruscans had established control in the region by the late 7th century BC, forming the aristocratic. According to legend, Rome was founded on April 21,753 BC by twin descendants of the Trojan prince Aeneas, Romulus and Remus. As the city was bereft of women, legend says that the Latins invited the Sabines to a festival and stole their unmarried maidens, leading to the integration of the Latins and the Sabines. Archaeological evidence indeed shows first traces of settlement at the Roman Forum in the mid-8th century BC, the seventh and final king of Rome was Tarquinius Superbus. As the son of Tarquinius Priscus and the son-in-law of Servius Tullius, Superbus was of Etruscan birth and it was during his reign that the Etruscans reached their apex of power. Superbus removed and destroyed all the Sabine shrines and altars from the Tarpeian Rock, the people came to object to his rule when he failed to recognize the rape of Lucretia, a patrician Roman, at the hands of his own son. Lucretias kinsman, Lucius Junius Brutus, summoned the Senate and had Superbus, after Superbus expulsion, the Senate voted to never again allow the rule of a king and reformed Rome into a republican government in 509 BC. In fact the Latin word Rex meaning King became a dirty and hated throughout the Republic. In 510, Spartan troops helped the Athenians overthrow the tyrant Hippias, cleomenes I, king of Sparta, put in place a pro-Spartan oligarchy conducted by Isagoras. Greece entered the 4th century under Spartan hegemony, but by 395 BC the Spartan rulers removed Lysander from office, and Sparta lost her naval supremacy. Athens, Argos, Thebes and Corinth, the two of which were formerly Spartan allies, challenged Spartan dominance in the Corinthian War, which ended inconclusively in 387 BC
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Islamic Golden Age
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This period is traditionally said to have ended with the collapse of the Abbasid caliphate due to Mongol invasions and the Sack of Baghdad in 1258 AD. A few contemporary scholars place the end of the Islamic Golden Age as late as the end of 15th to 16th centuries, the metaphor of a golden age began to be applied in 19th-century literature about Islamic history, in the context of the western aesthetic fashion known as Orientalism. There is no definition of term, and depending on whether it is used with a focus on cultural or on military achievement. During the early 20th century, the term was used only occasionally, the Muslim government heavily patronized scholars. The money spent on the Translation Movement for some translations is estimated to be equivalent to twice the annual research budget of the United Kingdom’s Medical Research Council. The best scholars and notable translators, such as Hunayn ibn Ishaq, had salaries that are estimated to be the equivalent of professional athletes today, the House of Wisdom was a library established in Abbasid-era Baghdad, Iraq by Caliph al-Mansur. During this period, the Muslims showed a strong interest in assimilating the knowledge of the civilizations that had been conquered. They also excelled in fields, in particular philosophy, science. For a long period of time the personal physicians of the Abbasid Caliphs were often Assyrian Christians, among the most prominent Christian families to serve as physicians to the caliphs were the Bukhtishu dynasty. Throughout the 4th to 7th centuries, Christian scholarly work in the Greek, the House of Wisdom was founded in Baghdad in 825, modelled after the Academy of Gondishapur. It was led by Christian physician Hunayn ibn Ishaq, with the support of Byzantine medicine, many of the most important philosophical and scientific works of the ancient world were translated, including the work of Galen, Hippocrates, Plato, Aristotle, Ptolemy and Archimedes. Many scholars of the House of Wisdom were of Christian background, the use of paper spread from China into Muslim regions in the eighth century, arriving in Al-Andalus on the Iberian peninsula, present-day Spain in the 10th century. It was easier to manufacture than parchment, less likely to crack than papyrus, Islamic paper makers devised assembly-line methods of hand-copying manuscripts to turn out editions far larger than any available in Europe for centuries. It was from countries that the rest of the world learned to make paper from linen. Ibn Rushd and Ibn Sina played a role in saving the works of Aristotle, whose ideas came to dominate the non-religious thought of the Christian. Ibn Sina and other such as al-Kindi and al-Farabi combined Aristotelianism and Neoplatonism with other ideas introduced through Islam. Arabic philosophic literature was translated into Latin and Ladino, contributing to the development of modern European philosophy, during this period, non-Muslims were allowed to flourish relative to treatment of religious minorities in the Christian Byzantine Empire. The Jewish philosopher Moses Maimonides, who lived in Andalusia, is an example, in epistemology, Ibn Tufail wrote the novel Hayy ibn Yaqdhan and in response Ibn al-Nafis wrote the novel Theologus Autodidactus
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Middle Ages
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In the history of Europe, the Middle Ages or Medieval Period lasted from the 5th to the 15th century. It began with the fall of the Western Roman Empire and merged into the Renaissance, the Middle Ages is the middle period of the three traditional divisions of Western history, classical antiquity, the medieval period, and the modern period. The medieval period is subdivided into the Early, High. Population decline, counterurbanisation, invasion, and movement of peoples, the large-scale movements of the Migration Period, including various Germanic peoples, formed new kingdoms in what remained of the Western Roman Empire. In the seventh century, North Africa and the Middle East—once part of the Byzantine Empire—came under the rule of the Umayyad Caliphate, although there were substantial changes in society and political structures, the break with classical antiquity was not complete. The still-sizeable Byzantine Empire survived in the east and remained a major power, the empires law code, the Corpus Juris Civilis or Code of Justinian, was rediscovered in Northern Italy in 1070 and became widely admired later in the Middle Ages. In the West, most kingdoms incorporated the few extant Roman institutions, monasteries were founded as campaigns to Christianise pagan Europe continued. The Franks, under the Carolingian dynasty, briefly established the Carolingian Empire during the later 8th, the Crusades, first preached in 1095, were military attempts by Western European Christians to regain control of the Holy Land from Muslims. Kings became the heads of centralised nation states, reducing crime and violence, intellectual life was marked by scholasticism, a philosophy that emphasised joining faith to reason, and by the founding of universities. Controversy, heresy, and the Western Schism within the Catholic Church paralleled the conflict, civil strife. Cultural and technological developments transformed European society, concluding the Late Middle Ages, the Middle Ages is one of the three major periods in the most enduring scheme for analysing European history, classical civilisation, or Antiquity, the Middle Ages, and the Modern Period. Medieval writers divided history into periods such as the Six Ages or the Four Empires, when referring to their own times, they spoke of them as being modern. In the 1330s, the humanist and poet Petrarch referred to pre-Christian times as antiqua, leonardo Bruni was the first historian to use tripartite periodisation in his History of the Florentine People. Bruni and later argued that Italy had recovered since Petrarchs time. The Middle Ages first appears in Latin in 1469 as media tempestas or middle season, in early usage, there were many variants, including medium aevum, or middle age, first recorded in 1604, and media saecula, or middle ages, first recorded in 1625. The alternative term medieval derives from medium aevum, tripartite periodisation became standard after the German 17th-century historian Christoph Cellarius divided history into three periods, Ancient, Medieval, and Modern. The most commonly given starting point for the Middle Ages is 476, for Europe as a whole,1500 is often considered to be the end of the Middle Ages, but there is no universally agreed upon end date. English historians often use the Battle of Bosworth Field in 1485 to mark the end of the period
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Renaissance
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The Renaissance was a period in European history, from the 14th to the 17th century, regarded as the cultural bridge between the Middle Ages and modern history. It started as a movement in Italy in the Late Medieval period and later spread to the rest of Europe. This new thinking became manifest in art, architecture, politics, science, Early examples were the development of perspective in oil painting and the recycled knowledge of how to make concrete. Although the invention of movable type sped the dissemination of ideas from the later 15th century. In politics, the Renaissance contributed to the development of the customs and conventions of diplomacy, the Renaissance began in Florence, in the 14th century. Other major centres were northern Italian city-states such as Venice, Genoa, Milan, Bologna, the word Renaissance, literally meaning Rebirth in French, first appeared in English in the 1830s. The word also occurs in Jules Michelets 1855 work, Histoire de France, the word Renaissance has also been extended to other historical and cultural movements, such as the Carolingian Renaissance and the Renaissance of the 12th century. The Renaissance was a movement that profoundly affected European intellectual life in the early modern period. Renaissance scholars employed the humanist method in study, and searched for realism, however, a subtle shift took place in the way that intellectuals approached religion that was reflected in many other areas of cultural life. In addition, many Greek Christian works, including the Greek New Testament, were back from Byzantium to Western Europe. Political philosophers, most famously Niccolò Machiavelli, sought to describe life as it really was. Others see more competition between artists and polymaths such as Brunelleschi, Ghiberti, Donatello, and Masaccio for artistic commissions as sparking the creativity of the Renaissance. Yet it remains much debated why the Renaissance began in Italy, accordingly, several theories have been put forward to explain its origins. During the Renaissance, money and art went hand in hand, Artists depended entirely on patrons while the patrons needed money to foster artistic talent. Wealth was brought to Italy in the 14th, 15th, and 16th centuries by expanding trade into Asia, silver mining in Tyrol increased the flow of money. Luxuries from the Eastern world, brought home during the Crusades, increased the prosperity of Genoa, unlike with Latin texts, which had been preserved and studied in Western Europe since late antiquity, the study of ancient Greek texts was very limited in medieval Western Europe. One of the greatest achievements of Renaissance scholars was to bring this entire class of Greek cultural works back into Western Europe for the first time since late antiquity, Arab logicians had inherited Greek ideas after they had invaded and conquered Egypt and the Levant. Their translations and commentaries on these ideas worked their way through the Arab West into Spain and Sicily and this work of translation from Islamic culture, though largely unplanned and disorganized, constituted one of the greatest transmissions of ideas in history
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Mariner's astrolabe
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Not an astrolabe proper, the mariners astrolabe was rather a graduated circle with an alidade used to measure vertical angles. They were designed to allow for their use on boats in rough water and/or in heavy winds, in the sixteenth century, the instrument was also called a ring. The Corpus Christi Museum of Science and History in Texas, United States, contains the worlds oldest mariners astrolabe with a date of 1554. Many dates can be found for the appearance of the first mariners astrolabes, the earliest date,1295, is offered by the Majorcan astronomer Ramon Llull. In any event, the instrument was known by the end of the 15th century. Nevertheless, the creation and perfecting of the astrolabe is attributed to Portuguese navigators during the beginning of Portuguese discoveries. The mariners astrolabe would have replaced or complemented instruments such as the staff or quadrant as a navigators instrument. The mariners astrolabe was used until the middle or, at the latest and it was replaced by more accurate and easier-to-use instruments such as the Davis quadrant and stratocaster. Although their heavy brass construction permits their longevity in marine environments, in 1979, only 35 were known to exist. While 65 were known by 1988, the biggest collection remains in museums in Portugal. Mariners astrolabes were made of brass, early sea astrolabes were made from sheets of brass. Due to their weight, they tended to perform poorly at sea. Heavier cast brass frames began to be made in the century and were considerably better. As the accuracy of the instrument is related to the radius of the divided circle, since the large plate form of the planispheric astrolabe makes it sensitive to the wind, the mariners astrolabe is made with a frame form. The openings in the frame allow wind to pass through, inducing less motion in the instrument, the essential function of the device was to measure angles. Thus the instrument featured a ring graduated in degrees, early instruments were only graduated for 90°, later instruments were graduated for the full 360° circle around the limb. The sole purpose of the spokes was to support the point for the alidade. This is clearly evident in the lower left instrument seen in the photograph above, the alidade was free to rotate about a pin through the centre of the instrument
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Oxford English Dictionary
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The Oxford English Dictionary is a descriptive dictionary of the English language, published by the Oxford University Press. The second edition came to 21,728 pages in 20 volumes, in 1895, the title The Oxford English Dictionary was first used unofficially on the covers of the series, and in 1928 the full dictionary was republished in ten bound volumes. In 1933, the title The Oxford English Dictionary fully replaced the name in all occurrences in its reprinting as twelve volumes with a one-volume supplement. More supplements came over the years until 1989, when the edition was published. Since 2000, an edition of the dictionary has been underway. The first electronic version of the dictionary was available in 1988. The online version has been available since 2000, and as of April 2014 was receiving two million hits per month. The third edition of the dictionary will probably appear in electronic form, Nigel Portwood, chief executive of Oxford University Press. As a historical dictionary, the Oxford English Dictionary explains words by showing their development rather than merely their present-day usages, therefore, it shows definitions in the order that the sense of the word began being used, including word meanings which are no longer used. The format of the OEDs entries has influenced numerous other historical lexicography projects and this influenced later volumes of this and other lexicographical works. As of 30 November 2005, the Oxford English Dictionary contained approximately 301,100 main entries, the dictionarys latest, complete print edition was printed in 20 volumes, comprising 291,500 entries in 21,730 pages. The longest entry in the OED2 was for the verb set, as entries began to be revised for the OED3 in sequence starting from M, the longest entry became make in 2000, then put in 2007, then run in 2011. Despite its impressive size, the OED is neither the worlds largest nor the earliest exhaustive dictionary of a language, the Dutch dictionary Woordenboek der Nederlandsche Taal is the worlds largest dictionary, has similar aims to the OED and took twice as long to complete. Another earlier large dictionary is the Grimm brothers dictionary of the German language, begun in 1838, the official dictionary of Spanish is the Diccionario de la lengua española, and its first edition was published in 1780. The Kangxi dictionary of Chinese was published in 1716, trench suggested that a new, truly comprehensive dictionary was needed. On 7 January 1858, the Society formally adopted the idea of a new dictionary. Volunteer readers would be assigned particular books, copying passages illustrating word usage onto quotation slips, later the same year, the Society agreed to the project in principle, with the title A New English Dictionary on Historical Principles. He withdrew and Herbert Coleridge became the first editor, on 12 May 1860, Coleridges dictionary plan was published and research was started
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Al-Biruni
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Abū Rayḥān Muḥammad ibn Aḥmad Al-Bīrūnī, known as Al-Biruni in English, was an Iranian scholar and polymath from Khwarezm. He studied almost all fields of science and was compensated for his research, royalty and powerful members of society sought out Al-Biruni to conduct research and study in order to uncover certain findings. He lived during the Islamic Golden Age, in which scholarly thought went hand in hand with the thinking and methodology of the Islamic religion. In addition to type of influence, Al-Biruni was also influenced by other nations, such as the Greek. He was conversant in Khwarezmian, Persian, Arabic, Sanskrit and he spent a large part of his life in Ghazni in modern-day Afghanistan, capital of the Ghaznavid dynasty which was based in what is now central-eastern Afghanistan. In 1017 he traveled to the Indian subcontinent and authored Tarikh Al-Hind after exploring the Hindu faith practised in India and he was given the title founder of Indology. He was a writer on customs and creeds of various nations. He also made contributions to Earth sciences, and is regarded as the father of geodesy for his important contributions to that field and he was born in the outer district of Kath, the capital of the Afrighid dynasty of Khwarezm. The word Biruni means from the outer-district in Persian, and so became his nisba. Al-Birunis relatives also took interest in the studies of science as well and he even had ties to royalty as there are links in his family to the families of prestigious elites. In order to conduct his research, Al-Biruni used different types of methods to tackle the different fields he studied, people consider Al-Biruni to be one of the greatest scientists in history and especially of Islam because of his discoveries and methodology. He lived during the Islamic Golden Age, which promoted astronomy and he was sympathetic to the Afrighids, who were overthrown by the rival dynasty of Mamunids in 995. He left his homeland for Bukhara, then under the Samanid ruler Mansur II the son of Nuh, there he corresponded with Avicenna and there are extant exchanges of views between these two scholars. In 998, he went to the court of the Ziyarid amir of Tabaristan and he also visited the court of the Bavandid ruler Al-Marzuban. Accepting the definite demise of the Afrighids at the hands of the Mamunids and their court at Gorganj was gaining fame for its gathering of brilliant scientists. In 1017, Mahmud of Ghazni took Rey, most scholars, including al-Biruni, were taken to Ghazni, the capital of the Ghaznavid dynasty. Biruni was made court astrologer and accompanied Mahmud on his invasions into India and he was forty-four years old when he went on the journeys with Mahmud of Ghazni. Biruni became acquainted with all related to India
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Muhammad ibn Musa al-Khwarizmi
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Muḥammad ibn Mūsā al-Khwārizmī, formerly Latinized as Algoritmi, was a Persian mathematician, astronomer, and geographer during the Abbasid Caliphate, a scholar in the House of Wisdom in Baghdad. In the 12th century, Latin translations of his work on the Indian numerals introduced the decimal number system to the Western world. Al-Khwārizmīs The Compendious Book on Calculation by Completion and Balancing presented the first systematic solution of linear and he is often considered one of the fathers of algebra. He revised Ptolemys Geography and wrote on astronomy and astrology, some words reflect the importance of al-Khwārizmīs contributions to mathematics. Algebra is derived from al-jabr, one of the two operations he used to solve quadratic equations, algorism and algorithm stem from Algoritmi, the Latin form of his name. His name is also the origin of guarismo and of algarismo, few details of al-Khwārizmīs life are known with certainty. He was born in a Persian family and Ibn al-Nadim gives his birthplace as Khwarezm in Greater Khorasan, muhammad ibn Jarir al-Tabari gives his name as Muḥammad ibn Musá al-Khwārizmiyy al-Majūsiyy al-Quṭrubbaliyy. The epithet al-Qutrubbulli could indicate he might instead have come from Qutrubbul and this would not be worth mentioning if a series of errors concerning the personality of al-Khwārizmī, occasionally even the origins of his knowledge, had not been made. Recently, G. J. Toomer. with naive confidence constructed an entire fantasy on the error which cannot be denied the merit of amusing the reader. Regarding al-Khwārizmīs religion, Toomer writes, Another epithet given to him by al-Ṭabarī, al-Majūsī, Ibn al-Nadīms Kitāb al-Fihrist includes a short biography on al-Khwārizmī together with a list of the books he wrote. Al-Khwārizmī accomplished most of his work in the period between 813 and 833, douglas Morton Dunlop suggests that it may have been possible that Muḥammad ibn Mūsā al-Khwārizmī was in fact the same person as Muḥammad ibn Mūsā ibn Shākir, the eldest of the three Banū Mūsā. Al-Khwārizmīs contributions to mathematics, geography, astronomy, and cartography established the basis for innovation in algebra, on the Calculation with Hindu Numerals written about 825, was principally responsible for spreading the Hindu–Arabic numeral system throughout the Middle East and Europe. It was translated into Latin as Algoritmi de numero Indorum, al-Khwārizmī, rendered as Algoritmi, led to the term algorithm. Some of his work was based on Persian and Babylonian astronomy, Indian numbers, al-Khwārizmī systematized and corrected Ptolemys data for Africa and the Middle East. Another major book was Kitab surat al-ard, presenting the coordinates of places based on those in the Geography of Ptolemy but with improved values for the Mediterranean Sea, Asia and he also wrote on mechanical devices like the astrolabe and sundial. He assisted a project to determine the circumference of the Earth and in making a map for al-Mamun. When, in the 12th century, his works spread to Europe through Latin translations, the Compendious Book on Calculation by Completion and Balancing is a mathematical book written approximately 830 CE. The term algebra is derived from the name of one of the operations with equations described in this book
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Hellenistic period
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It is often considered a period of transition, sometimes even of decadence or degeneration, compared to the enlightenment of the Greek Classical era. The Hellenistic period saw the rise of New Comedy, Alexandrian poetry, the Septuagint, Greek science was advanced by the works of the mathematician Euclid and the polymath Archimedes. The religious sphere expanded to include new gods such as the Greco-Egyptian Serapis, eastern deities such as Attis and Cybele, the Hellenistic period was characterized by a new wave of Greek colonization which established Greek cities and kingdoms in Asia and Africa. This resulted in the export of Greek culture and language to new realms. Equally, however, these new kingdoms were influenced by the cultures, adopting local practices where beneficial, necessary. Hellenistic culture thus represents a fusion of the Ancient Greek world with that of the Near East, Middle East and this mixture gave rise to a common Attic-based Greek dialect, known as Koine Greek, which became the lingua franca through the Hellenistic world. Scholars and historians are divided as to what event signals the end of the Hellenistic era, Hellenistic is distinguished from Hellenic in that the first encompasses the entire sphere of direct ancient Greek influence, while the latter refers to Greece itself. The word originated from the German term hellenistisch, from Ancient Greek Ἑλληνιστής, from Ἑλλάς, Hellenistic is a modern word and a 19th-century concept, the idea of a Hellenistic period did not exist in Ancient Greece. Although words related in form or meaning, e. g, the major issue with the term Hellenistic lies in its convenience, as the spread of Greek culture was not the generalized phenomenon that the term implies. Some areas of the world were more affected by Greek influences than others. The Greek population and the population did not always mix, the Greeks moved and brought their own culture. While a few fragments exist, there is no surviving historical work which dates to the hundred years following Alexanders death. The works of the major Hellenistic historians Hieronymus of Cardia, Duris of Samos, the earliest and most credible surviving source for the Hellenistic period is Polybius of Megalopolis, a statesman of the Achaean League until 168 BC when he was forced to go to Rome as a hostage. His Histories eventually grew to a length of forty books, covering the years 220 to 167 BC, another important source, Plutarchs Parallel Lives though more preoccupied with issues of personal character and morality, outlines the history of important Hellenistic figures. Appian of Alexandria wrote a history of the Roman empire that includes information of some Hellenistic kingdoms, other sources include Justins epitome of Pompeius Trogus Historiae Philipicae and a summary of Arrians Events after Alexander, by Photios I of Constantinople. Lesser supplementary sources include Curtius Rufus, Pausanias, Pliny, in the field of philosophy, Diogenes Laertius Lives and Opinions of Eminent Philosophers is the main source. Ancient Greece had traditionally been a collection of fiercely independent city-states. After the Peloponnesian War, Greece had fallen under a Spartan hegemony, in which Sparta was pre-eminent but not all-powerful
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Apollonius of Perga
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Apollonius of Perga was a Greek geometer and astronomer known for his theories on the topic of conic sections. Beginning from the theories of Euclid and Archimedes on the topic and his definitions of the terms ellipse, parabola, and hyperbola are the ones in use today. Apollonius worked on other topics, including astronomy. Most of the work has not survived except in references in other authors. His hypothesis of eccentric orbits to explain the apparently aberrant motion of the planets, for such an important contributor to the field of mathematics, scant biographical information remains. The 6th century Palestinian commentator, Eutocius of Ascalon, on Apollonius’ major work, Conics, states, “Apollonius, the geometrician. Came from Perga in Pamphylia in the times of Ptolemy Euergetes, the ruins of the city yet stand. It was a center of Hellenistic culture, Euergetes, “benefactor, ” identifies Ptolemy III Euergetes, third Greek dynast of Egypt in the diadochi succession. Presumably, his “times” are his regnum, 246-222/221 BC, times are always recorded by ruler or officiating magistrate, so that if Apollonius was born earlier than 246, it would have been the “times” of Euergetes’ father. The identity of Herakleios is uncertain, the approximate times of Apollonius are thus certain, but no exact dates can be given. The figure Specific birth and death years stated by the scholars are only speculative. Eutocius appears to associate Perga with the Ptolemaic dynasty of Egypt, never under Egypt, Perga in 246 BC belonged to the Seleucid Empire, an independent diadochi state ruled by the Seleucid dynasty. Someone designated “of Perga” might well be expected to have lived and worked there, to the contrary, if Apollonius was later identified with Perga, it was not on the basis of his residence. The remaining autobiographical material implies that he lived, studied and wrote in Alexandria, philip was assassinated in 336 BC. Alexander went on to fulfill his plan by conquering the vast Iranian empire, the material is located in the surviving false “Prefaces” of the books of his Conics. These are letters delivered to friends of Apollonius asking them to review the book enclosed with the letter. The Preface to Book I, addressed to one Eudemus, reminds him that Conics was initially requested by a house guest at Alexandria, Naucrates had the first draft of all eight books in his hands by the end of the visit. Apollonius refers to them as being “without a thorough purgation” and he intended to verify and emend the books, releasing each one as it was completed
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Hipparchus
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Hipparchus of Nicaea was a Greek astronomer, geographer, and mathematician. He is considered the founder of trigonometry but is most famous for his discovery of precession of the equinoxes. Hipparchus was born in Nicaea, Bithynia, and probably died on the island of Rhodes and he is known to have been a working astronomer at least from 162 to 127 BC. Hipparchus is considered the greatest ancient astronomical observer and, by some and he was the first whose quantitative and accurate models for the motion of the Sun and Moon survive. For this he made use of the observations and perhaps the mathematical techniques accumulated over centuries by the Babylonians. He developed trigonometry and constructed trigonometric tables, and he solved problems of spherical trigonometry. With his solar and lunar theories and his trigonometry, he may have been the first to develop a method to predict solar eclipses. Relatively little of Hipparchuss direct work survives into modern times, although he wrote at least fourteen books, only his commentary on the popular astronomical poem by Aratus was preserved by later copyists. There is a tradition that Hipparchus was born in Nicaea, in the ancient district of Bithynia. His birth date was calculated by Delambre based on clues in his work, Hipparchus must have lived some time after 127 BC because he analyzed and published his observations from that year. Hipparchus obtained information from Alexandria as well as Babylon, but it is not known when or if he visited these places and he is believed to have died on the island of Rhodes, where he seems to have spent most of his later life. It is not known what Hipparchuss economic means were nor how he supported his scientific activities and his appearance is likewise unknown, there are no contemporary portraits. In the 2nd and 3rd centuries coins were made in his honour in Bithynia that bear his name and show him with a globe, this supports the tradition that he was born there. As an astronomer of antiquity his influence, supported by ideas from Aristotle, held sway for nearly 2000 years, Hipparchuss only preserved work is Τῶν Ἀράτου καὶ Εὐδόξου φαινομένων ἐξήγησις. This is a critical commentary in the form of two books on a popular poem by Aratus based on the work by Eudoxus. Hipparchus also made a list of his works, which apparently mentioned about fourteen books. His famous star catalog was incorporated into the one by Ptolemy, the first trigonometric table was apparently compiled by Hipparchus, who is now consequently known as the father of trigonometry. There are a variety of mis-steps in the more ambitious 2005 paper, According to one book review, both of these claims have been rejected by other scholars
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Planisphere
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In astronomy, planisphere is a star chart analog computing instrument in the form of two adjustable disks that rotate on a common pivot. It can be adjusted to display the stars for any time. It is an instrument to assist in learning how to recognize stars, the astrolabe, an instrument that has its origins in Hellenistic astronomy, is a predecessor of the modern planisphere. The term planisphere contrasts with armillary sphere, where the sphere is represented by a three-dimensional framework of rings. The chart and overlay are mounted so that they are free to rotate about a pivot point at their centers. The star chart contains the brightest stars, constellations and deep-sky objects visible from a latitude on Earth. The night sky that one sees from the Earth depends on whether the observer is in the northern or southern hemispheres, a planisphere window is designed for a particular latitude and will be accurate enough for a certain band either side of that. Planisphere makers will usually offer them in a number of versions for different latitudes, planispheres only show the stars visible from the observers latitude, stars below the horizon are not included. A complete twenty-four-hour time cycle is marked on the rim of the overlay, a full twelve months of calendar dates are marked on the rim of the starchart. The window is marked to show the direction of the eastern and western horizons, the disk and overlay are adjusted so that the observers local time of day on the overlay corresponds to that days date on the star chart disc. The portion of the star visible in the window then represents the distribution of stars in the sky at that moment for the planispheres designed location. Users hold the planisphere above their head with the eastern and western horizons correctly aligned to match the chart to actual star positions, the word planisphere was originally used in the second century by Ptolemy to describe the representation of a spherical Earth by a map drawn in the plane. This usage continued into the Renaissance, for example Gerardus Mercator described his 1569 world map as a planisphere, in this article the word describes the representation of the star-filled celestial sphere on the plane. The first star chart to have the name planisphere was made in 1624 by Jacob Bartsch, Bartsch was the son-in-law of Johannes Kepler, discoverer of Keplers laws of planetary motion. Since the planisphere shows the sphere in a printed flat. Planispheres, like all charts, are using a certain projection method. For planispheres there are two methods in use, leaving the choice with the designer. One such method is the azimuthal equidistant projection
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Dioptra
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A dioptra is a classical astronomical and surveying instrument, dating from the 3rd century BCE. The dioptra was a tube or, alternatively, a rod with a sight at both ends, attached to a stand. If fitted with protractors, it could be used to measure angles, greek astronomers used the dioptra to measure the positions of stars, both Euclid and Geminus refer to the dioptra in their astronomical works. By the time of Ptolemy, it was obsolete as an astronomical instrument and it continued in use as an effective surveying tool. Adapted to surveying, the dioptra is similar to the theodolite, or surveyors transit and it is a more accurate version of the groma. The dioptra may have been sophisticated enough, for example, to construct a tunnel through two points in a mountain. There is some speculation that it may have used to build the Eupalinian aqueduct. Scholars disagree whether the dioptra was available that early, an entire book about the construction and surveying usage of the dioptra is credited to Hero of Alexandria. Hero was one of history’s most ingenious engineers and applied mathematicians, the dioptra was used extensively on aqueduct building projects. Screw turns on different parts of the instrument made it easy to calibrate for very precise measurements The dioptra was replaced as a surveying instrument by the theodolite. Alidade Isaac Moreno Gallo The Dioptra Tesis and reconstructon of the Dioptra, the History and Practice of Ancient Astronomy, pages 34-35. Oxford University Press. net Tom M. Apostol, The Tunnel of Samos, Engineering and Science,64, 30-40
30.
Ptolemy
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Claudius Ptolemy was a Greek writer, known as a mathematician, astronomer, geographer, astrologer, and poet of a single epigram in the Greek Anthology. He lived in the city of Alexandria in the Roman province of Egypt, wrote in Koine Greek, beyond that, few reliable details of his life are known. His birthplace has been given as Ptolemais Hermiou in the Thebaid in a statement by the 14th-century astronomer Theodore Meliteniotes. This is a very late attestation, however, and there is no reason to suppose that he ever lived elsewhere than Alexandria. Ptolemy wrote several treatises, three of which were of importance to later Byzantine, Islamic and European science. The first is the astronomical treatise now known as the Almagest, although it was entitled the Mathematical Treatise. The second is the Geography, which is a discussion of the geographic knowledge of the Greco-Roman world. The third is the treatise in which he attempted to adapt horoscopic astrology to the Aristotelian natural philosophy of his day. This is sometimes known as the Apotelesmatika but more known as the Tetrabiblos from the Greek meaning Four Books or by the Latin Quadripartitum. The name Claudius is a Roman nomen, the fact that Ptolemy bore it indicates he lived under the Roman rule of Egypt with the privileges and political rights of Roman citizenship. It would have suited custom if the first of Ptolemys family to become a citizen took the nomen from a Roman called Claudius who was responsible for granting citizenship, if, as was common, this was the emperor, citizenship would have been granted between AD41 and 68. The astronomer would also have had a praenomen, which remains unknown and it occurs once in Greek mythology, and is of Homeric form. All the kings after him, until Egypt became a Roman province in 30 BC, were also Ptolemies, abu Mashar recorded a belief that a different member of this royal line composed the book on astrology and attributed it to Ptolemy. The correct answer is not known”, Ptolemy wrote in Greek and can be shown to have utilized Babylonian astronomical data. He was a Roman citizen, but most scholars conclude that Ptolemy was ethnically Greek and he was often known in later Arabic sources as the Upper Egyptian, suggesting he may have had origins in southern Egypt. Later Arabic astronomers, geographers and physicists referred to him by his name in Arabic, Ptolemys Almagest is the only surviving comprehensive ancient treatise on astronomy. Ptolemy presented his models in convenient tables, which could be used to compute the future or past position of the planets. The Almagest also contains a catalogue, which is a version of a catalogue created by Hipparchus
31.
Tetrabiblos
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But whilst the Almagest as an astronomical authority was superseded by acceptance of the heliocentric model of the solar system, the Tetrabiblos remains an important theoretical work for astrology. This allowed Ptolemaic teachings on astrology to be included in universities during the Renaissance, the books intellectual standing had collapsed by the end of the 17th century, when Ptolemys work and the principles it presented faced criticisms of being outmoded and based on superstition. The historical importance of the Tetrabiblos is seen by the ancient, Medieval. It was copied, commented on, paraphrased, abridged, the latest critical Greek edition, by Wolfgang Hübner, was published by Teubner in 1998. Ptolemy is referred to as the most famous of Greek astrologers, as a source of reference his Tetrabiblos is described as having enjoyed almost the authority of a Bible among the astrological writers of a thousand years or more. Compiled in Alexandria in the 2nd century, the work gathered commentaries about it from its first publication and it was translated into Arabic in the 9th century, and is described as by far the most influential source of medieval Islamic astrology. With the translation of the Tetrabiblos into Latin in the 12th century, Ptolemaic astrology became integrated by Albertus Magnus and this theological acceptance encouraged the teaching of Ptolemaic astrology in universities, often linked to medical studies. This, in turn, brought attention in literary works, such as Dantes, at this time, the contents of the Tetrabiblos started to draw stigmatisation as part of a diabolical art of divination. One 17th-century critic was to write of its subject, no art is more fitted to forward the aims of the devil than the astrology of Ptolemy. The early 20th-century Humanist astrologer Dane Rudhyar reported that the astrology of his era originated almost entirely in the work of the Alexandrian astrologer, even 21st-century astrological textbooks have described the Tetrabiblos as being without a doubt, indispensable for any serious student of astrology. The outstanding mark of Ptolemy’s astrology is described as informed by the philosophical, the book opens with an explanation of the philosophical framework of astrology which aims to answer the arguments of critics who questioned the subjects validity. Ptolemy was not responsible for originating the astrological techniques he presented in the Tetrabiblos and his contribution was to arrange the material systematically, in order to demonstrate that astrology is based upon logical, hierarchical principles. The Greek text has undergone transmission into Arabic, Latin and many modern languages, an ancient anonymous commentary on the work states that some considered the term Tetrabiblos to be a fictitious name. Hübner, editor of the 1998 Teubner Greek edition, uses the title Apotelesmatiká, effects, alexander Jones, editor of the Springer publication Ptolemy in Perspective considers that Ptolemys own title remains unknown, but agrees that the term Apotelesmatika is a credible guess. D. The text begins with Ptolemys address to Syrus, a character to whom all Ptolemys works are dedicated. He states that each has its own science and the former is desirable in its own even though it does not attain the result given by its combination with the second. Chapters 2 and 3 are important for giving Ptolemys philosophical defense of his subject, Franz Boll noticed the arguments were paralleled in older sources, particularly those of the Stoic philosopher Posidonius. Ptolemy then answers each criticism in the two chapters
32.
Hypatia
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Hypatia, often called Hypatia of Alexandria, was a Greek mathematician, astronomer, and philosopher in Egypt, then a part of the Eastern Roman Empire. She was the head of the Neoplatonic school at Alexandria, where she taught philosophy, the mathematician and philosopher Hypatia of Alexandria was the only daughter of the mathematician Theon of Alexandria. Around 400, she became head of the Neoplatonist School in Alexandria, where she imparted the knowledge of Plato and Aristotle to students, including pagans, Christians, however, not all Christians were as hostile towards her, some Christians even used Hypatia as symbolic of Virtue. Having succeeded to the school of Plato and Plotinus, she explained the principles of philosophy to her auditors, many of whom came from a distance to receive her instructions. On account of the self-possession and ease of manner which she had acquired in consequence of the cultivation of her mind, neither did she feel abashed in going to an assembly of men. For all men on account of her dignity and virtue admired her the more. Hypatia corresponded with former pupil Synesius, who was tutored by her in the school of Platonism and later became bishop of Ptolemais in 410. Together with the references by the pagan philosopher Damascius, these are the extant records left by Hypatias pupils at the Platonist school of Alexandria. Hypatia was murdered during an episode of city-wide anger stemming from a feud between Orestes, the prefect of Alexandria, and Cyril, the Bishop of Alexandria and her death is symbolic for some historians. On the other hand, Christian Wildberg notes that Hellenistic philosophy continued to flourish in the 5th and 6th centuries, of the many accounts of Hypatias death, the most complete is the one written around 415 by Socrates Scholasticus and included in the Historia Ecclesiastica. According to this account, in 415 a feud began over Jewish dancing exhibitions in Alexandria, Orestes, the Roman governor of Alexandria, and Cyril, the Bishop of Alexandria, engaged in a bitter feud in which Hypatia eventually became a main point of contention. Orestes published an edict that outlined new regulations for such gatherings, the edict angered Christians as well as Jews. At one such gathering, Hierax, a devout Christian follower of Cyril, read the edict, many people felt that Hierax was attempting to incite the crowd into sedition. Orestes reacted swiftly and violently out of what Scholasticus suspected was jealousy the growing power of the bishops… encroached on the jurisdiction of the authorities and he ordered Hierax to be seized and tortured publicly in the theater. Hearing of Hieraxs severe and public punishment, Cyril threatened to retaliate against the Jews of Alexandria with the utmost severities if the harassment of Christians did not cease immediately. In response to Cyrils threat, the Jews of Alexandria grew even more furious, Socrates of Constantinoples account says that the Jews had plotted to flush out the Christians at night by running through the streets claiming that the Church of Alexander was on fire. The feud between Cyril and Orestes intensified because of things, and both men wrote to the emperor regarding the situation. Eventually, Cyril attempted to out to Orestes through several peace overtures
33.
Byzantine Empire
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It survived the fragmentation and fall of the Western Roman Empire in the 5th century AD and continued to exist for an additional thousand years until it fell to the Ottoman Turks in 1453. During most of its existence, the empire was the most powerful economic, cultural, several signal events from the 4th to 6th centuries mark the period of transition during which the Roman Empires Greek East and Latin West divided. Constantine I reorganised the empire, made Constantinople the new capital, under Theodosius I, Christianity became the Empires official state religion and other religious practices were proscribed. Finally, under the reign of Heraclius, the Empires military, the borders of the Empire evolved significantly over its existence, as it went through several cycles of decline and recovery. During the reign of Maurice, the Empires eastern frontier was expanded, in a matter of years the Empire lost its richest provinces, Egypt and Syria, to the Arabs. This battle opened the way for the Turks to settle in Anatolia, the Empire recovered again during the Komnenian restoration, such that by the 12th century Constantinople was the largest and wealthiest European city. Despite the eventual recovery of Constantinople in 1261, the Byzantine Empire remained only one of several small states in the area for the final two centuries of its existence. Its remaining territories were annexed by the Ottomans over the 15th century. The Fall of Constantinople to the Ottoman Empire in 1453 finally ended the Byzantine Empire, the term comes from Byzantium, the name of the city of Constantinople before it became Constantines capital. This older name of the city would rarely be used from this point onward except in historical or poetic contexts. The publication in 1648 of the Byzantine du Louvre, and in 1680 of Du Canges Historia Byzantina further popularised the use of Byzantine among French authors, however, it was not until the mid-19th century that the term came into general use in the Western world. The Byzantine Empire was known to its inhabitants as the Roman Empire, the Empire of the Romans, Romania, the Roman Republic, Graikia, and also as Rhōmais. The inhabitants called themselves Romaioi and Graikoi, and even as late as the 19th century Greeks typically referred to modern Greek as Romaika and Graikika. The authority of the Byzantine emperor as the legitimate Roman emperor was challenged by the coronation of Charlemagne as Imperator Augustus by Pope Leo III in the year 800. No such distinction existed in the Islamic and Slavic worlds, where the Empire was more seen as the continuation of the Roman Empire. In the Islamic world, the Roman Empire was known primarily as Rûm, the Roman army succeeded in conquering many territories covering the entire Mediterranean region and coastal regions in southwestern Europe and north Africa. These territories were home to different cultural groups, both urban populations and rural populations. The West also suffered heavily from the instability of the 3rd century AD
34.
Syriac language
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Syriac /ˈsɪri. æk/, also known as Syriac Aramaic, is a dialect of Middle Aramaic that was once spoken across much of the Fertile Crescent and Eastern Arabia. Indeed, Syriac literature comprises roughly 90% of the extant Aramaic literature, Old Aramaic was adopted by the Neo-Assyrian Empire when they conquered the various Aramean city-kingdoms to its west. The Achaemenid Empire, which rose after the fall of the Assyrian Empire, also adopted Old Aramaic as its official language, during the course of the third and fourth centuries AD, the inhabitants of the region began to embrace Christianity. Along with Latin and Greek, Syriac became one of the three most important Christian languages in the centuries of the Christian Era. Primarily a Christian medium of expression, Syriac had a cultural and literary influence on the development of Arabic. Syriac remains the language of Syriac Christianity to this day. Syriac is a Middle Aramaic language and, as such, a language of the Northwestern branch of the Semitic family and it is written in the Syriac alphabet, a derivation of the Aramaic alphabet. Syriac was the local accent of Aramaic in Edessa, that evolved under the influence of Church of the East and it has been found as far afield as Hadrians Wall in Ancient Britain, with inscriptions written by Assyrian and Aramean soldiers of the Roman Empire. Modern Syriac/Modern Syriac Aramaic is an occasionally used to refer to the modern Eastern Aramaic languages. In this terminology, Modern Syriac is divided into, Modern Western Syriac Aramaic, note however that these are sometimes excluded from the category of Modern Syriac. The modern varieties are, therefore, not discussed in this article, in 132 BC, the kingdom of Osroene was founded in Edessa and Proto-Syriac evolved in that kingdom. Many Syriac-speakers still look to Edessa as the cradle of their language, there are about eighty extant early Syriac inscriptions, dated to the first three centuries AD. All of these examples of the language are non-Christian. As an official language, Syriac was given a relatively coherent form, style, in the 3rd century, churches in Edessa began to use Syriac as the language of worship. There is evidence that the adoption of Syriac, the language of the Assyrian people, was to effect mission, much literary effort was put into the production of an authoritative translation of the Bible into Syriac, the Peshitta. At the same time, Ephrem the Syrian was producing the most treasured collection of poetry, in 489, many Syriac-speaking Christians living in the eastern reaches of the Roman Empire fled to the Sassanid Empire to escape persecution and growing animosity with Greek-speaking Christians. The Christological differences with the Church of the East led to the bitter Nestorian schism in the Syriac-speaking world, as a result, Syriac developed distinctive western and eastern varieties. Syriac literature is by far the most prodigious of the various Aramaic languages and its corpus covers poetry, prose, theology, liturgy, hymnody, history, philosophy, science, medicine and natural history
35.
Nasir al-Din al-Tusi
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Khawaja Muhammad ibn Muhammad ibn al-Hasan al-Tūsī, better known as Nasīr al-Dīn Tūsī, was a Persian polymath, architect, philosopher, physician, scientist, theologian and Marja Taqleed. He was of the Twelver Shī‘ah Islamic belief, the Muslim scholar Ibn Khaldun considered Tusi to be the greatest of the later Persian scholars. Nasir al-Din Tusi was born in the city of Tus in medieval Khorasan in the year 1201, in Hamadan and Tus he studied the Quran, Hadith, Shia jurisprudence, logic, philosophy, mathematics, medicine and astronomy. He was apparently born into a Shī‘ah family and lost his father at a young age, at a young age he moved to Nishapur to study philosophy under Farid al-Din Damad and mathematics under Muhammad Hasib. He met also Farid al-Din Attar, the legendary Sufi master who was killed by Mongol invaders. In Mosul he studied mathematics and astronomy with Kamal al-Din Yunus and he was captured after the invasion of the Alamut castle by the Mongol forces. Tusi has about 150 works, of which 25 are in Persian and the remaining are in Arabic, here are some of his major works, Kitāb al-Shakl al-qattāʴ Book on the complete quadrilateral. A five volume summary of trigonometry, al-Tadhkirah fiilm al-hayah – A memoir on the science of astronomy. Many commentaries were written about this work called Sharh al-Tadhkirah - Commentaries were written by Abd al-Ali ibn Muhammad ibn al-Husayn al-Birjandi, akhlaq-i Nasiri – A work on ethics. Al-Risalah al-Asturlabiyah – A Treatise on astrolabe, Zij-i ilkhani – A major astronomical treatise, completed in 1272. Sharh al-isharat Awsaf al-Ashraf a short work in Persian Tajrīd al-iʿtiqād – A commentary on Shia doctrines. During his stay in Nishapur, Tusi established a reputation as an exceptional scholar, tusi’s prose writing, which number over 150 works, represent one of the largest collections by a single Islamic author. Writing in both Arabic and Persian, Nasir al-Din Tusi dealt with religious topics and non-religious or secular subjects. His works include the definitive Arabic versions of the works of Euclid, Archimedes, Ptolemy, Autolycus, Tusi convinced Hulegu Khan to construct an observatory for establishing accurate astronomical tables for better astrological predictions. Beginning in 1259, the Rasad Khaneh observatory was constructed in Azarbaijan, south of the river Aras, and to the west of Maragheh, the capital of the Ilkhanate Empire. Based on the observations in this for the time being most advanced observatory and this book contains astronomical tables for calculating the positions of the planets and the names of the stars. His model for the system is believed to be the most advanced of his time. Between Ptolemy and Copernicus, he is considered by many to be one of the most eminent astronomers of his time, for his planetary models, he invented a geometrical technique called a Tusi-couple, which generates linear motion from the sum of two circular motions
36.
Paris
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Paris is the capital and most populous city of France. It has an area of 105 square kilometres and a population of 2,229,621 in 2013 within its administrative limits, the agglomeration has grown well beyond the citys administrative limits. By the 17th century, Paris was one of Europes major centres of finance, commerce, fashion, science, and the arts, and it retains that position still today. The aire urbaine de Paris, a measure of area, spans most of the Île-de-France region and has a population of 12,405,426. It is therefore the second largest metropolitan area in the European Union after London, the Metropole of Grand Paris was created in 2016, combining the commune and its nearest suburbs into a single area for economic and environmental co-operation. Grand Paris covers 814 square kilometres and has a population of 7 million persons, the Paris Region had a GDP of €624 billion in 2012, accounting for 30.0 percent of the GDP of France and ranking it as one of the wealthiest regions in Europe. The city is also a rail, highway, and air-transport hub served by two international airports, Paris-Charles de Gaulle and Paris-Orly. Opened in 1900, the subway system, the Paris Métro. It is the second busiest metro system in Europe after Moscow Metro, notably, Paris Gare du Nord is the busiest railway station in the world outside of Japan, with 262 millions passengers in 2015. In 2015, Paris received 22.2 million visitors, making it one of the top tourist destinations. The association football club Paris Saint-Germain and the rugby union club Stade Français are based in Paris, the 80, 000-seat Stade de France, built for the 1998 FIFA World Cup, is located just north of Paris in the neighbouring commune of Saint-Denis. Paris hosts the annual French Open Grand Slam tennis tournament on the red clay of Roland Garros, Paris hosted the 1900 and 1924 Summer Olympics and is bidding to host the 2024 Summer Olympics. The name Paris is derived from its inhabitants, the Celtic Parisii tribe. Thus, though written the same, the name is not related to the Paris of Greek mythology. In the 1860s, the boulevards and streets of Paris were illuminated by 56,000 gas lamps, since the late 19th century, Paris has also been known as Panam in French slang. Inhabitants are known in English as Parisians and in French as Parisiens and they are also pejoratively called Parigots. The Parisii, a sub-tribe of the Celtic Senones, inhabited the Paris area from around the middle of the 3rd century BC. One of the areas major north-south trade routes crossed the Seine on the île de la Cité, this place of land and water trade routes gradually became a town
37.
Iran
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Iran, also known as Persia, officially the Islamic Republic of Iran, is a sovereign state in Western Asia. Comprising a land area of 1,648,195 km2, it is the second-largest country in the Middle East, with 82.8 million inhabitants, Iran is the worlds 17th-most-populous country. It is the country with both a Caspian Sea and an Indian Ocean coastline. The countrys central location in Eurasia and Western Asia, and its proximity to the Strait of Hormuz, Tehran is the countrys capital and largest city, as well as its leading economic and cultural center. Iran is the site of to one of the worlds oldest civilizations, the area was first unified by the Iranian Medes in 625 BC, who became the dominant cultural and political power in the region. The empire collapsed in 330 BC following the conquests of Alexander the Great, under the Sassanid Dynasty, Iran again became one of the leading powers in the world for the next four centuries. Beginning in 633 AD, Arabs conquered Iran and largely displaced the indigenous faiths of Manichaeism and Zoroastrianism by Islam, Iran became a major contributor to the Islamic Golden Age that followed, producing many influential scientists, scholars, artists, and thinkers. During the 18th century, Iran reached its greatest territorial extent since the Sassanid Empire, through the late 18th and 19th centuries, a series of conflicts with Russia led to significant territorial losses and the erosion of sovereignty. Popular unrest culminated in the Persian Constitutional Revolution of 1906, which established a monarchy and the countrys first legislative body. Following a coup instigated by the U. K. Growing dissent against foreign influence and political repression led to the 1979 Revolution, Irans rich cultural legacy is reflected in part by its 21 UNESCO World Heritage Sites, the third-largest number in Asia and 11th-largest in the world. Iran is a member of the UN, ECO, NAM, OIC. Its political system is based on the 1979 Constitution which combines elements of a democracy with a theocracy governed by Islamic jurists under the concept of a Supreme Leadership. A multicultural country comprising numerous ethnic and linguistic groups, most inhabitants are Shia Muslims, the largest ethnic groups in Iran are the Persians, Azeris, Kurds and Lurs. Historically, Iran has been referred to as Persia by the West, due mainly to the writings of Greek historians who called Iran Persis, meaning land of the Persians. As the most extensive interactions the Ancient Greeks had with any outsider was with the Persians, however, Persis was originally referred to a region settled by Persians in the west shore of Lake Urmia, in the 9th century BC. The settlement was then shifted to the end of the Zagros Mountains. In 1935, Reza Shah requested the international community to refer to the country by its native name, opposition to the name change led to the reversal of the decision, and Professor Ehsan Yarshater, editor of Encyclopædia Iranica, propagated a move to use Persia and Iran interchangeably
38.
Celestial coordinate system
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In astronomy, a celestial coordinate system is a system for specifying positions of celestial objects, satellites, planets, stars, galaxies, and so on. Coordinate systems can specify a position in 3-dimensional space, or merely the direction of the object on the celestial sphere, the coordinate systems are implemented in either spherical coordinates or rectangular coordinates. Spherical coordinates, projected on the sphere, are analogous to the geographic coordinate system used on the surface of the Earth. These differ in their choice of fundamental plane, which divides the sphere into two equal hemispheres along a great circle. Rectangular coordinates, in units, are simply the cartesian equivalent of the spherical coordinates, with the same fundamental plane. Each coordinate system is named after its choice of fundamental plane, the following table lists the common coordinate systems in use by the astronomical community. The fundamental plane divides the sphere into two equal hemispheres and defines the baseline for the latitudinal coordinates, similar to the equator in the geographic coordinate system. The poles are located at ±90° from the fundamental plane, the primary direction is the starting point of the longitudinal coordinates. The origin is the distance point, the center of the celestial sphere. The horizontal, or altitude-azimuth, system is based on the position of the observer on Earth, the positioning of a celestial object by the horizontal system varies with time, but is a useful coordinate system for locating and tracking objects for observers on Earth. It is based on the position of relative to an observers ideal horizon. The equatorial coordinate system is centered at Earths center, but fixed relative to the celestial poles, the coordinates are based on the location of stars relative to Earths equator if it were projected out to an infinite distance. The equatorial describes the sky as seen from the solar system, the equatorial system is the normal coordinate system for most professional and many amateur astronomers having an equatorial mount that follows the movement of the sky during the night. Celestial objects are found by adjusting the telescopes or other instruments scales so that they match the equatorial coordinates of the object to observe. There are also subdivisions into mean of date coordinates, which average out or ignore nutation, and true of date, the fundamental plane is the plane of the Earths orbit, called the ecliptic plane. The geocentric ecliptic system was the coordinate system for ancient astronomy and is still useful for computing the apparent motions of the Sun, Moon. The heliocentric ecliptic system describes the orbital movement around the Sun. The system is used for computing the positions of planets and other solar system bodies
39.
Geographic coordinate system
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A geographic coordinate system is a coordinate system used in geography that enables every location on Earth to be specified by a set of numbers, letters or symbols. The coordinates are chosen such that one of the numbers represents a vertical position. A common choice of coordinates is latitude, longitude and elevation, to specify a location on a two-dimensional map requires a map projection. The invention of a coordinate system is generally credited to Eratosthenes of Cyrene. Ptolemy credited him with the adoption of longitude and latitude. Ptolemys 2nd-century Geography used the prime meridian but measured latitude from the equator instead. Mathematical cartography resumed in Europe following Maximus Planudes recovery of Ptolemys text a little before 1300, in 1884, the United States hosted the International Meridian Conference, attended by representatives from twenty-five nations. Twenty-two of them agreed to adopt the longitude of the Royal Observatory in Greenwich, the Dominican Republic voted against the motion, while France and Brazil abstained. France adopted Greenwich Mean Time in place of local determinations by the Paris Observatory in 1911, the latitude of a point on Earths surface is the angle between the equatorial plane and the straight line that passes through that point and through the center of the Earth. Lines joining points of the same latitude trace circles on the surface of Earth called parallels, as they are parallel to the equator, the north pole is 90° N, the south pole is 90° S. The 0° parallel of latitude is designated the equator, the plane of all geographic coordinate systems. The equator divides the globe into Northern and Southern Hemispheres, the longitude of a point on Earths surface is the angle east or west of a reference meridian to another meridian that passes through that point. All meridians are halves of great ellipses, which converge at the north and south poles, the prime meridian determines the proper Eastern and Western Hemispheres, although maps often divide these hemispheres further west in order to keep the Old World on a single side. The antipodal meridian of Greenwich is both 180°W and 180°E, the combination of these two components specifies the position of any location on the surface of Earth, without consideration of altitude or depth. The grid formed by lines of latitude and longitude is known as a graticule, the origin/zero point of this system is located in the Gulf of Guinea about 625 km south of Tema, Ghana. To completely specify a location of a feature on, in, or above Earth. Earth is not a sphere, but a shape approximating a biaxial ellipsoid. It is nearly spherical, but has an equatorial bulge making the radius at the equator about 0. 3% larger than the radius measured through the poles, the shorter axis approximately coincides with the axis of rotation
40.
Stereographic projection
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In geometry, the stereographic projection is a particular mapping that projects a sphere onto a plane. The projection is defined on the sphere, except at one point. Where it is defined, the mapping is smooth and bijective and it is conformal, meaning that it preserves angles. It is neither isometric nor area-preserving, that is, it preserves neither distances nor the areas of figures, intuitively, then, the stereographic projection is a way of picturing the sphere as the plane, with some inevitable compromises. In practice, the projection is carried out by computer or by using a special kind of graph paper called a stereographic net, shortened to stereonet. The stereographic projection was known to Hipparchus, Ptolemy and probably earlier to the Egyptians and it was originally known as the planisphere projection. Planisphaerium by Ptolemy is the oldest surviving document that describes it, one of its most important uses was the representation of celestial charts. The term planisphere is still used to refer to such charts, in the 16th and 17th century, the equatorial aspect of the stereographic projection was commonly used for maps of the Eastern and Western Hemispheres. It is believed that already the map created in 1507 by Gualterius Lud was in stereographic projection, as were later the maps of Jean Roze, Rumold Mercator, in star charts, even this equatorial aspect had been utilised already by the ancient astronomers like Ptolemy. François dAguilon gave the stereographic projection its current name in his 1613 work Opticorum libri sex philosophis juxta ac mathematicis utiles, in 1695, Edmond Halley, motivated by his interest in star charts, published the first mathematical proof that this map is conformal. He used the recently established tools of calculus, invented by his friend Isaac Newton and this section focuses on the projection of the unit sphere from the north pole onto the plane through the equator. Other formulations are treated in later sections, the unit sphere in three-dimensional space R3 is the set of points such that x2 + y2 + z2 =1. Let N = be the pole, and let M be the rest of the sphere. The plane z =0 runs through the center of the sphere, for any point P on M, there is a unique line through N and P, and this line intersects the plane z =0 in exactly one point P′. Define the stereographic projection of P to be this point P′ in the plane, in Cartesian coordinates on the sphere and on the plane, the projection and its inverse are given by the formulas =, =. In spherical coordinates on the sphere and polar coordinates on the plane, here, φ is understood to have value π when R =0. Also, there are ways to rewrite these formulas using trigonometric identities. In cylindrical coordinates on the sphere and polar coordinates on the plane, the projection is not defined at the projection point N =
41.
40th parallel north
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The 40th parallel north is a circle of latitude that is 40 degrees north of the Earths equatorial plane. It crosses Europe, the Mediterranean Sea, Asia, the Pacific Ocean, North America, at this latitude the sun is visible for 15 hours,1 minute during the summer solstice and 9 hours,20 minutes during the winter solstice. On 21 June, the altitude of the sun is 73.83 degrees and 26.17 degrees on 21 December. Starting in Spain at the Prime Meridian and heading eastwards, the parallel 40° north passes through, on 30 May 1854, the Kansas–Nebraska Act created the Territory of Kansas and the Territory of Nebraska divided by the parallel 40° north. Both territories were required to determine for themselves whether to permit slavery, open conflict between free-state and pro-slavery forces in the Kansas Territory was one of the root causes of the American Civil War. The parallel 40° north formed the northern boundary of the British Colony of Maryland. A subsequent royal grant gave the Colony of Pennsylvania land north of the 40th parallel but mistakenly assumed it would intersect the Twelve Mile Circle, pennsylvanias border was thus unclear and the colony pushed for a border far south of the 40th parallel. The Mason–Dixon Line was drawn between 1763 and 1767 as the boundary between the overlapping claims of these two colonies. The parallel 40° north passes through the cities of Philadelphia, Pennsylvania and Columbus, Ohio, as well as suburbs of Indianapolis, Indiana and Denver. Baseline Road in Boulder, Colorado, traces the parallel 40° north, thistle, Utah, a ghost town since 1983, is slightly below 40° north. 39th parallel north 41st parallel north Baseline Geological Exploration of the Fortieth Parallel
42.
Azimuth
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An azimuth is an angular measurement in a spherical coordinate system. An example is the position of a star in the sky, the star is the point of interest, the reference plane is the horizon or the surface of the sea, and the reference vector points north. The azimuth is the angle between the vector and the perpendicular projection of the star down onto the horizon. Azimuth is usually measured in degrees, the concept is used in navigation, astronomy, engineering, mapping, mining and artillery. In land navigation, azimuth is usually denoted alpha, α, azimuth has also been more generally defined as a horizontal angle measured clockwise from any fixed reference plane or easily established base direction line. Today, the plane for an azimuth is typically true north, measured as a 0° azimuth. Moving clockwise on a 360 degree circle, east has azimuth 90°, south 180°, there are exceptions, some navigation systems use south as the reference vector. Any direction can be the vector, as long as it is clearly defined. Quite commonly, azimuths or compass bearings are stated in a system in which either north or south can be the zero, the reference direction, stated first, is always north or south, and the turning direction, stated last, is east or west. The directions are chosen so that the angle, stated between them, is positive, between zero and 90 degrees. If the bearing happens to be exactly in the direction of one of the cardinal points and this is the reason why the X and Y axis in the above formula are swapped. If the azimuth becomes negative, one can always add 360°, the formula in radians would be slightly easier, α = atan2 Caveat, Most computer libraries reverse the order of the atan2 parameters. We are standing at latitude φ1, longitude zero, we want to find the azimuth from our viewpoint to Point 2 at latitude φ2, longitude L. The difference is usually small, if Point 2 is not more than 100 km away. Various websites will calculate geodetic azimuth, e. g. GeoScience Australia site, formulas for calculating geodetic azimuth are linked in the distance article. Normal-section azimuth is simpler to calculate, Bomford says Cunninghams formula is exact for any distance, replace φ2 with declination and longitude difference with hour angle, and change the sign. There is a variety of azimuthal map projections. They all have the property that directions from a point are preserved
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Horizon
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At many locations, the true horizon is obscured by trees, buildings, mountains, etc. and the resulting intersection of earth and sky is called the visible horizon. When looking at a sea from a shore, the part of the sea closest to the horizon is called the offing. The word horizon derives from the Greek ὁρίζων κύκλος horizōn kyklos, separating circle, from the verb ὁρίζω horizō, to divide, to separate, a pilot can also retain his or her spatial orientation by referring to the horizon. For observers near sea level the difference between this geometrical horizon and the horizon is imperceptible to the naked eye. In astronomy the horizon is the plane through the eyes of the observer. It is the plane of the horizontal coordinate system, the locus of points that have an altitude of zero degrees. While similar in ways to the horizon, in this context a horizon may be considered to be a plane in space. One typically sees further along the Earths curved surface than a simple geometric calculation allows for because of refraction error, the reverse happens if the ground is hotter than the air above it, as often happens in deserts, producing mirages. Examples, For an observer standing on the ground with h =1.70 metres, for an observer standing on the ground with h =2 metres, the horizon is at a distance of 5 kilometres. For an observer standing on a hill or tower of 100 metres in height, for an observer standing at the top of the Burj Khalifa, the horizon is at a distance of 103 kilometres. For an observer atop Mount Everest, the horizon is at a distance of 336 kilometres, with d in miles and h in feet, d ≈1.5 h ≈1.22 h. Examples, assuming no refraction, For an observer on the ground with eye level at h =5 ft 7 in, for an observer standing on a hill or tower 100 feet in height, the horizon is at a distance of 12.2 miles. For an observer on the summit of Aconcagua, the horizon to the west is at a distance of 184 miles. The secant-tangent theorem states that O C2 = O A × O B, the equation can also be derived using the Pythagorean theorem. Since the line of sight is a tangent to the Earth and this sets up a right triangle, with the sum of the radius and the height as the hypotenuse. Another relationship involves the distance s along the surface of the Earth to the horizon, with γ in radians, s = R γ. Solving for s gives s = R cos −1 R R + h, the distances d and s are nearly the same when the height of the object is negligible compared to the radius. If the observer is close to the surface of the earth, then it is valid to disregard h in the term, and the formula becomes d =2 R h
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