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In the History Of Astronomy , Islamic astronomy or '''Arabic astronomy''' refers to the astronomical developments made by the Islamic Civilisation between the 8th and 15th centuries. It closely parallels the genesis of other Islamic Sciences in its assimilation of foreign material and the amalgamation of the disparate elements of that material to create a science that was essentially Islam ic. These included Indian , Sassanid and Hellenistic works in particular, which were translated and built upon. Some stars in the sky, such as Aldebaran , are still today recognized with their Arabic names. HISTORY Pre- Islam ic Arab s had no scientific astronomy. Their knowledge of stars was only Empirical , limited to what they observed regarding the rising and setting of stars. The rise of Islam provoked increased Arab thought in this field.Dallal (1999), p. 162 Foundations There are several . {Link without Title} Don't those who reject faith see that the heavens and the earth were a single entity then We ripped them apart? The foundations of Islamic astronomy closely parallels the genesis of other Islamic sciences in its assimilation of foreign material and the amalgamation of the disparate elements of that material to create a science that was essentially Islamic. These include Indian and Sassanid works in particular. Some Hellenistic texts were also translated and built upon as well. The science historian Donald Routledge Hill has divided the history of Islamic astronomy into the four following distinct time periods in its history. 700-825 The period of assimilation and syncretisation of earlier Hellenistic, Indian and Sassanid astronomy. During this period, a number of Sanskrit and Persian texts were translated into Arabic . The most notable of the texts was ''Zij al-Sindhind'',This book is not related to al-Khwarizmi's ''Zij al-Sindh''. On ''zijes'' see E. S. Kennedy, "A Survey of Islamic Astronomical Tables". based on the '' Surya Siddhanta '' and the works of Brahmagupta , and translated by Muhammad Al-Fazari and Yaqūb Ibn Tāriq in 777. Sources indicate that the text was translated after, in 770, an Indian Astronomer visited the court of Caliph Al-Mansur . Another text translated was the ''Zij al-Shah'', a collection of astronomical tables compiled in Persia over two centuries. Fragments of text during this period indicate that Arabs adopted the Sine Function (inherited from Indian Trigonometry ) instead of the Chord s of Arc used in Hellenistic mathematics. Islamic interest in Astronomy ran parallel to the interest in mathematics. Noteworthy in this regard was the '' Almagest '' of Egyptian astronomer Ptolemy (c. 100-178). The ''Almagest'' was a landmark work in its field, assembling, as Euclid 's '' Elements '' had previously done with geometrical works, all extant knowledge in the field of astromony that was known to the author. This work was originally known as ''The Mathematical Composition'', but after it had come to be used as a text in astronomy, it was called ''The Great Astronomer''. The Islamic world called it ''The Greatest'' prefixing the Greek work ''megiste'' (greatest) with the article ''al-'' and it has since been known to the world as ''Al-megiste'' or, after popular use in Western translation, ''Almagest''. Ptolemy also produced other works, such as ''Optics'', '' Harmonica '', and some suggest he also wrote ''Tetrabiblon''. The ''Almagest'' was a particularly unifying work for its exhaustive lists of Sidereal phenomena. He drew up a list of chronological tables of Assyria n, Persian , Greek , and Roman kings for use in reckoning the lapse of time between known astronomical events and fixed dates. In addition to its relevance to calculating accurate calendars, it linked far and foreign cultures together by a common interest in the stars and astrology. The work of Ptolemy was replicated and refined over the years under Arab , Persian and other Muslim astronomers and astrologers. 825-1025 , the father of Algebra and Algorithm s, wrote the '' Zij al-Sindh''.]] This period of vigorous investigation, in which the superiority of the Ptolemaic System of astronomy was accepted and significant contributions made to it. Astronomical research was greatly supported by the Abbasid Caliph Al-Mamun . 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-Khwarizimi 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. 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 and learning already discovered knowledge. Al-Khwarizmi's work marked the beginning of non-traditional methods of study and calculations.Dallal (1999), pg. 163 In 850, Al-Farghani wrote ''Kitab fi Jawani'' ("''A compendium of the science of stars''"). 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 Apogee s of the sun and the moon, and the circumference of the earth. The books were widely circulated through the Muslim world, and even translated into Latin .Dallal (1999), pg. 164 In the 9th century, the eldest Banū Mūsā brother, Muhammad Ibn Musa , in his ''Astral Motion'' and ''The Force of Attraction'', discovered that there was a Force of Attraction between heavenly bodies,K. A. Waheed (1978). ''Islam and The Origins of Modern Science'', p. 27. Islamic Publication Ltd., Lahore. foreshadowing Newton's Law Of Universal Gravitation . Robert Briffault (1938). ''The Making of Humanity'', p. 191. 1025-1450 During this period a distinctive Islamic system of astronomy flourished. Within the Greek tradition and its successors it was traditional to separate mathematical astronomy (as typified by , noted: Some Muslim scholars, including Al-Biruni , discussed whether the Earth moved and considered how this might be consistent with astronomical computations and physical systems.Teresi, et al., (2002) Several Muslim astronomers, most notably Nasīr Al-Dīn Al-Tūsī and his succesors at the Maragheh School , developed non-Ptolemaic computational models within a geocentric context that were later adapted in the Copernican Model in a Heliocentric context. Theories and observations was the first to conduct elaborate Experiment s related to astronomical phenomena, and he introduced the analysis of the Acceleration of planets, discovered that the motions of the Solar Apogee and Precession are not identical, discussed the possibility of Heliocentrism , and suggested that the Earth's Rotation on its axis would be consistent with his astronomical parameters.]] In the 11th century, . In 1030, Abū Al-Rayhān Al-Bīrūnī discussed the Indian Planetary Theories of Aryabhata , Brahmagupta and Varahamihira in his ''Ta'rikh al-Hind'' (Latinized as ''Indica''). Biruni stated that Brahmagupta and others consider that the Earth Rotates on its axis and Biruni noted that this does not create any mathematical problems.S. H. Nasr, ''Islamic Cosmological Doctrines'', p. 135, n. 13 Abu Said Sinjari, a contemporary of al-Biruni, suggested the possible heliocentric movement of the Earth around the Sun, which al-Biruni did not reject.A. Baker, L. Chapter (2002) Al-Biruni agreed with the . In 1031, al-Biruni completed his extensive astronomical encyclopaedia ''Kitab al-Qanun al-Mas'udi'' ( (1980), "Al-Biruni", in Joseph Strayer, ''Dictionary of the Middle Ages'', Vol. 2, p. 249. Charles Scribner's Sons, New York. Al-Biruni also described the Earth's Gravitation as: In 1121, Al-Khazini , in his treatise ''The Book of the Balance of Wisdom'', states:Salah Zaimeche PhD (2005). Merv , p. 7. Foundation for Science Technology and Civilization. Al-Khazini was thus the first to propose the theory that the Gravities of bodies vary depending on their distances from the centre of the Earth. This phenomenon was not proven until Newton's Law Of Universal Gravitation in the 18th century. Beginning of ''hay'a'' tradition (Alhacen) was a pioneer of the Muslim ''haya'' tradition of astronomy, presented the first critique and reform of Ptolemy 's model, and laid the theoretical foundations for modern Telescopic astronomy.]] Between 1025 and 1028, Ibn Al-Haytham ( Latin ized as Alhacen), began the ''hay'a'' tradition of Islamic astronomy with his ''Al-Shuku ala Batlamyus'' (''Doubts on Ptolemy''). While maintaining the physical reality of the Geocentric Model , he was the first to criticize Ptolemy 's astronomical system, for relating actual physical motions to imaginary mathematical points, lines, and circles: Ibn al-Haytham developed a physical structure of the Ptolemaic system in his ''Treatise on the configuration of the World'', or ''Maqâlah fî ''hay'at'' al-‛âlam'', which became an influential work in the ''hay'a'' tradition.Y. Tzvi Langermann, ed. and trans., ''Ibn al-Haytham's'' On the Configuration of the World, Harvard Dissertations in the History of Science, (New York: Garland, 1990), pp. 25-34 In his ''Epitome of Astronomy'', he was also the first to insist that the heavenly bodies "were accountable to the astronomy can also be traced back to Ibn al-Haytham, due to the influence of his Optical studies on the later development of the modern telescope.O. S. Marshall (1950). "Alhazen and the Telescope", ''Astronomical Society of the Pacific Leaflets'' 6, p. 4. In 1038, Ibn al-Haytham described the first non-Ptolemaic configuration in ''The Model of the Motions''. His reform excluded Cosmology , as he developed a systematic study of celestial Kinematics that was completely Geometric . This in turn led to innovative developments in Infinitesimal Geometry .Rashed (2007). His reformed model was the first to reject the Equant Rashed (2007), p. 20, 53. and Eccentrics ,Rashed (2007), p. 33-34. free celestial kinematics from cosmology, and reduce physical entities to geometrical entities. The model also propounded the Earth's Rotation about its axis,Rashed (2007), p. 20, 32-33. and the centres of motion were geometrical points without any physical significance, like Johannes Kepler 's model centuries later.Rashed (2007), p. 51-52. Ibn al-Haytham also describes an early version of Occam's Razor , where he employs only minimal hypotheses regarding the properties that characterize astronomical motions, as he attempts to eliminate from his planetary model the Cosmological hypotheses that cannot be observed from Earth .Rashed (2007), p. 35-36. In 1070, Abu Ubayd Al-Juzjani , a pupil of Avicenna , proposed a non-Ptolemaic configuration in his ''Tarik al-Aflak''. In his work, he indicated the so-called " Equant " problem of the Ptolemic model, and proposed a solution for the problem. He claimed that his teacher Avicenna had also worked out the equant problem. A. I. Sabra (1998). "Configuring the Universe: Aporetic, Problem Solving, and Kinematic Modeling as Themes of Arabic Astronomy", ''Perspectives on Science'' 6 (3), p. 288-330 {Link without Title} . Andalusian school rejected the Eccentric Deferents introduced by Ptolemy . He rejected the Ptolemaic Model and instead argued for a strictly Concentric model of the universe.]] In the 11th-12th centuries, astronomers in Al-Andalus took up the challenge earlier posed by Ibn al-Haytham, namely to develop an alternate non-Ptolemaic configuration that evaded the errors found in the Ptolemaic Model .George Saliba (1981). "''Geschichte des arabischen Schriftiums. Band VI: Astronomie bis ca. 430 H'' by F. Sezgin", ''Journal of the American Oriental Society'' 101 (2), p. 219-221 {Link without Title} . Like Ibn al-Haytham's critique, the anonymous Andalusian work, ''al-Istidrak ala Batlamyus'' (''Recapitulation regarding Ptolemy''), included a list of objections to Ptolemic astronomy. In the late 11th century, Al-Zarqali (Latinized as Arzachel) discovered that the orbits of the planets are Ellipse s and not circles, Robert Briffault (1938). ''The Making of Humanity'', p. 190. though he still followed the Ptolemaic model. In the 12th century, Averroes rejected the Eccentric Deferents introduced by Ptolemy . He rejected the Ptolemaic Model and instead argued for a strictly Concentric model of the universe. He wrote the following criticism on the Ptolemaic model of planetary motion:Owen Gingerich (April 1986). "Islamic astronomy", ''Scientific American'' 254 (10), p. 74. Averroes' contemporary, Maimonides , wrote the following on the planetary model proposed by Ibn Bajjah (Avempace): Later in the 12th century, Ibn Bajjah's successors, . mainly because they followed Aristotle 's notion of perfect circular motion. Maragheh school See Also: Maragheh observatory resolved significant problems in the Ptolemaic System with the Tusi-couple , which later played an important role in the Copernican Model .]] From the 13th century, astronomers of the Maragheh school, like the Andalusian astronomers, attempted to solve the Equant problem and produce alternative configurations to the Ptolemaic Model . They were more successful than their Andalusian predecessors in producing non-Ptolemaic configurations, which eliminated the equant and Eccentrics , that were just as accurate as the Ptolemaic model in numerically predicting planetary positions. The most important of the Maragheh astronomers included Mo'ayyeduddin Urdi (d. 1266), Nasir Al-Din Al-Tusi (1201-1274), 'Umar al-Katibi al- Qazwini (d. 1277), Qutb Al-Din Al-Shirazi (1236-1311), Sadr al-Sharia al-Bukhari (c. 1347), Ibn Al-Shatir (1304-1375), Ala al-Qushji (c. 1474), and Shams al-Din al-Khafri (d. 1550).Dallal (1999), pg. 171 orbits.Richard Covington (2007). Tusi's student Qutb Al-Din Al-Shirazi (1236-1311), in his ''The Limit of Accomplishment concerning Knowledge of the Heavens'', discussed the possibility of Heliocentrism . 'Umar al-Katibi al- Qazwini (d. 1277), who also worked at the Maragheh observatory, in his ''Hikmat al-'Ain'', wrote an argument for a heliocentric model, though he later abandoned the idea. Ibn Al-Shatir ( 1304 – 1375 ), in ''A Final Inquiry Concerning the Rectification of Planetary Theory'', incorporated the Urdi lemma, and eliminated the need for an equant by introducing an extra epicycle (the Tusi-couple), departing from the Ptolemaic system in a way that was mathematically identical to what Nicolaus Copernicus did in the 16th century. Ibn al-Shatir's system was also only approximately geocentric, rather than exactly so, having demonstrated Trigonometrically that the Earth was not the exact center of the universe. Y. M. Faruqi wrote:Y. M. Faruqi (2006). "Contributions of Islamic scholars to the scientific enterprise", ''International Education Journal'' 7 (4), p. 395-396.
Ibn al-Shatir’s rectified model, which included the Tusi-couple and Urdi lemma, was later adapted into a Heliocentric Model by Copernicus, which was mathematically achieved by reversing the direction of the last vector connecting the Earth to the Sun in Ibn al-Shatir's model.Saliba (1999). In the published version of his masterwork, '' De Revolutionibus Orbium Coelestium '', Copernicus also cites the theories of Al-Battani , Arzachel and Averroes as influences, while the works of Ibn Al-Haytham (Alhacen) and Al-Biruni were also known in Europe at the time. 1450-1900 The period of stagnation, when the traditional system of astronomy continued to be practised with enthusiasm, but with rapidly decreasing innovation of any major significance. This view, however, has been questioned by George Saliba after studying the works of the 16th century astronomer Shams al-Din al-Khafri (d. 1550), a commentator on earlier Maragheh Astronomers . Saliba wrote the following on al-Khafri's work: A large corpus of literature from Islamic astronomy remains today, numbering around at least 10,000 manuscript volumes scattered throughout the world, much of which has not been read or even catalogued. Even so, a reasonably accurate picture of Islamic activity in the field of astronomy can be reconstructed. 's ''The Depiction of Celestial Constellations''. The constellation pictured here is Sagittarius .]] OBSERVATORIES The first systematic observations in Islam are reported to have taken place under the patronage of Al-Mamun . Here, and in many other private observatories from Damascus to Baghdad , Meridian degrees were measured, solar parameters were established, and detailed observations of the Sun , Moon , and Planets were undertaken. In the 10th century, the Buwayhid dynasty encouraged the undertaking of extensive works in Astronomy, such as the construction of a large scale instrument with which observations were made in the year 950CE. We know of this by recordings made in the ''zij'' of astronomers such as Ibn Al-Alam . The great astronomer Abd Al-Rahman Al Sufi was patronised by prince Adud O-dowleh , who systematically revised Ptolemy 's catalogue of Star s. Sharaf Al-Daula also established a similar observatory in Baghdad . And reports by Ibn Yunus and Al-Zarqall in Toledo and Cordoba indicate the use of sophisticated instruments for their time. It was Malik Shah I who established the first large observatory, probably in Isfahan . It was here where Omar Khayyám with many other collaborators constructed a Zij and formulated the Persian Solar Calendar a.k.a. the ''jalali calendar''. A modern version of this calendar is still in official use in Iran today. Maragheh observatory See Also: Maragheh observatory The most influential observatory, however, was the Maragheh Observatory founded by Nasīr Al-Dīn Al-Tūsī under the patronage of Hulegu Khan in the 13th century. Here, al-Tusi supervised its technical construction at Maragheh . The facility contained resting quarters for Hulagu Khan , as well as a library and mosque. Some of the top astronomers of the day gathered there, and from their collaboration resulted important modifications to the Ptolemaic System over a period of 50 years. , founder of a large Islamic observatory in Samarkand , honoured on this Soviet stamp.]] Samarkand and Istanbul observatories In 1420, prince Ulugh Beg , himself an astronomer and mathematician, founded another large observatory in Samarkand , the remains of which were excavated in 1908 by Russian teams. And finally, ''Taqi al-din bin Ma'ruf'' founded a large observatory in Istanbul in 1575, which was on the same scale as those in Maragha and Samarkand. Modern observatories In modern times, has modern facilities at Shiraz University and Tabriz University . In Dec 2005, '' Physics Today '' reported of Iranian plans to construct a "world class" facility with a 2.0 m telescope observatory in the near future. {Link without Title} depicting an epicyclic planetary model.]] INSTRUMENTS See Also: Inventions in the Muslim world Modern knowledge of the instruments used by Muslim astronomers primarily comes from two sources. First the remaining instruments in private and museum collections today, and second the treatises and manuscripts preserved from the Middle Ages. Muslims made many improvements to instruments already in use before their time, such as adding new scales or details. Their contributions to astronomical instrumentation are abundant. Astrolabes Brass astrolabe Brass , corresponding to 927-8CE). The first person credited for building the Astrolabe in the Islamic world is reportedly Fazari ( Richard Nelson Frye : Golden Age of Persia. p163). He only improved it though, the Greeks had already invented astrolabes to chart the stars. The Arabs then took it during the Abbasid Dynasty and perfected it to be used to find the beginning of Ramadan, the hours of prayer, and the direction of Mecca. in Cambridge , England.]] Saphaea The first astrolabe instruments were used to read the rise of the time of rise of the Sun and fixed stars. Arzachel (Al-Zarqali) of Al-Andalus constructed one such instrument in which, unlike its predecessors, did not depend on the latitude of the observer, and could be used anywhere. This instrument became known in Europe as the "Saphaea". Mechanical geared astrolabes The first . Orthographical astrolabe Abu Rayhan Al-Biruni invented and wrote the earliest treatise on the Orthographical astrolabe in the 1000s . Khwarizm , Foundation for Science Technology and Civilisation. Linear astrolabe A famous work by ''. Analog computers Equatorium The Equatorium was invented by Abū Ishāq Ibrāhīm Al-Zarqālī (Arzachel) in Al-Andalus , probably around 1015 CE. It is a mechanical device for finding the positions of the Moon , Sun , and Planet s, without calculation using a geometrical model to represent the Celestial Body 's mean and anomalistic position. Planisphere Abu Rayhan Al-Biruni invented and wrote the earliest treatise on the Planisphere in the 1000s . Mechanical geared calendar computer Abū Rayhān Al-Bīrūnī invented the first Mechanical Lunisolar Calendar Computer which employed a Gear Train and eight Gear -wheels. Donald Routledge Hill (1985). "Al-Biruni's mechanical calendar", ''Annals of Science'' 42, p. 139-163. This was an early example of a fixed- Wire d knowledge processing Machine .Tuncer Oren (2001). "Advances in Computer and Information Sciences: From Abacus to Holonic Agents", ''Turk J Elec Engin'' '''9''' (1), p. 63-70 {Link without Title} . Astrolabe with geared calendar computer In 1235, Abi Bakr of . Armillary spheres and spherical astrolabes An Armillary Sphere had similar applications to a Celestial Globe . No early Islamic armillary spheres survive, but several treatises on “the instrument with the rings” were written. In this context there is also an Islamic development, the Spherical Astrolabe , of which only one complete instrument, from the 14th century, has survived. Astronomical clock The Muslims constructed a variety of highly accurate Astronomical Clock s for use in their observatories.Ajram (1992). Celestial globes Celestial Globe s were used primarily for solving problems in celestial astronomy. Today, 126 such instruments remain worldwide, the oldest from the 11th century. The altitude of the sun, or the Right Ascension and Declination of stars could be calculated with these by inputting the location of the observer on the Meridian Ring of the globe. Hodometer Abū Rayhān Al-Bīrūnī invented an early Hodometer in the 11th Century .D. De S. Price (1984). "A History of Calculating Machines", ''IEEE Micro'' 4 (1), p. 22-52. This was an early example of a fixed- Wire d knowledge processing Machine . Quadrants Several forms of Quadrant s were invented by Muslims. Among them was the sine quadrant used for astronomical calculations and various forms of the horary quadrant, used to determine time (especially the times of prayer) by observations of the Sun or stars. A center of the development of quadrants was ninth-century Baghdad . David A. King , "Islamic Astronomy", in Christopher Walker (1999), ed., ''Astronomy before the telescope'', p. 167-168. British Museum Press. ISBN 0-7141-2733-7. Sextant The first Sextant was constructed in Ray, Iran , by Abu-Mahmud Al-Khujandi in 994 . It was a very large sextant that achieved a high level of accuracy for Astronomical measurements, which he described his in his treatise, ''On the obliquity of the ecliptic and the latitudes of the cities''. Sundials Muslims made several important improvements to the theory and construction of Sundial s, which they inherited from their Indian and Hellenistic predecessors. Khwarizmi made tables for these instruments which considerably shortened the time needed to make specific calculations. Sundials were frequently placed on mosques to determine the time of prayer. One of the most striking examples was built in the 14th century by the ''muwaqqit'' (timekeeper) of the Umayyid Mosque in Damascus , Ibn Al-Shatir .David A. King, "Islamic Astronomy," pp. 168-9. FAMOUS MUSLIM ASTRONOMY BOOKS
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