Islamic astronomy comprises the astronomical developments made in the Islamic world, particularly during the Islamic Golden Age (9th–13th centuries),and mostly written in the Arabic language. These developments mostly took place in the Middle East, Central Asia, Al-Andalus, and North Africa, and later in the Far East and India. 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 with Islamic characteristics. These included Greek, Sassanid, and Indian works in particular, which were translated and built upon.
Islamic astronomy played a significant role in the revival of Byzantineand European astronomy following the loss of knowledge during the early medieval period, notably with the production of Latin translations of Arabic works during the 12th century. 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, many of which have not been read or catalogued. Even so, a reasonably accurate picture of Islamic activity in the field of astronomy can be reconstructed.
Ahmad Dallal notes that, unlike the Babylonians, Greeks, and Indians, who had developed elaborate systems of mathematical astronomical study, the pre-Islamic Arabs relied entirely on empirical observations. These observations were based on the rising and setting of particular stars, and this area of astronomical study was known as anwa. Anwa continued to be developed after Islamization by the Arabs, where Islamic astronomers added mathematical methods to their empirical observations.
While Abbasid era and later Muslim scholars made great contributions to astronomy,early scripture of the tafsir (or exegesis) of the Quran, and hadith (records of sayings and doings of the Prophet Muhammad) indicate early Muslims concepts of the universe were based on the appearance and movement of sun, moon, stars, and planets in the sky. and not the ideas of some Greek philosophers of the earth being spherical, the sun much larger than the earth and much more distant than the moon, etc. The Quran frequently mentions the "Earth" or "land" as "spreadout", a "bed", "carpet"; the heavens being a canopy or building (Q.2:22 binaa ( بِنَاء ) or binaan).
In Tafsir al-Jalalayn, Quranic scholar Jalāl al-Dīn al-Maḥallī (1389–1460 CE) writes about how scholars of Islamic law interpret verse Q.88:20 (which reads: "And the earth how it was laid out flat?" Wa-ila al-ardi kayfa sutihat, وَإِلَى ٱلۡأَرۡضِ كَیۡفَ سُطِحَتۡ):
"And the earth how it was laid out flat?" and thus infer from this the power of God exalted be He and His Oneness? The commencing with the mention of camels is because they are closer in contact with it the earth than any other animal. As for His words sutihat ‘laid out flat’ this on a literal reading suggests that the earth is flat which is the opinion of the scholars of the revealed Law ["وعليه علماء الشرع"] and not a sphere as astronomers [ahl al-hay’a, أهْل الهَيْئَة ] have it, even if this latter does not contradict any of the pillars of Islamic Law [الشَّرْع ].
Other scriptural references are also not consistent with a spherical earth. The literal meaning of Quranic verse Q.18:86: Till, when he reached the setting-place of the sun, he found it setting in a muddy spring, ...", is confirmed by Tafsir al-Tabari 18:86, where interpretations disagrees only on whether the verse means that the sun sets in a muddy (hami'ah) spring or a hot (hamiyah) spring.Tafsir al-Tabari for verse 2:22 includes a couple of narrations transmitted by a chain going back to early Muslims saying "...and the sky a canopy...", which al-Tabari (839–923 CE) interpreted to mean "The canopy of the sky over the earth is in the form of a dome, and it is a roof over the earth." A sahih hadith from Sunan Abu Dawood (Hadith 4002) also talks of Muhammad telling companion Abu Dharr al-Ghifari, "Do you know where this sets? ... It sets in a spring of warm water (Hamiyah)."
Following the Islamic conquests, under the early caliphate, Muslim scholars began to absorb Hellenistic and Indian astronomical knowledge via translations into Arabic (in some cases via Persian).
The first astronomical texts that were translated into Arabic were of Indianand Persian origin. The most notable of the texts was Zij al-Sindhind, an 8th-century Indian astronomical work that was translated by Muhammad ibn Ibrahim al-Fazari and Yaqub ibn Tariq after 770 CE with the assistance of Indian astronomers who visited the court of caliph Al-Mansur in 770. Another text translated was the Zij al-Shah, a collection of astronomical tables (based on Indian parameters) compiled in Sasanid Persia over two centuries. Fragments of texts during this period indicate that Arabs adopted the sine function (inherited from India) in place of the chords of arc used in Greek trigonometry.
According to David King, after the rise of Islam, the religious obligation to determine the qibla and prayer times inspired progress in astronomy.Early Islam's history shows evidence of a productive relationship between faith and science. Specifically, Islamic scientists took an early interest in astronomy, as the concept of keeping time accurately was important for the five daily prayers central to the faith. Early Islamicate scientists constructed astronomical tables specifically to determine the exact times of prayer for specific locations around the continent, serving effectively as an early system of time zones.
The House of Wisdom was an academy established in Baghdad under Abbasid caliph Al-Ma'mun in the early 9th century. 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 first major Muslim work of astronomy was Zij al-Sindhind by Persian mathematician 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. 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 nontraditional methods of study and calculations.
In 850, al-Farghani wrote Kitab fi Jawami (meaning "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 apogees of the Sun and the Moon, and the circumference of the Earth. The book was widely circulated through the Muslim world, and translated into Latin.
By the 10th century texts appeared regularly whose subject matter was doubts concerning Ptolemy (shukūk).Several Muslim scholars questioned the Earth's apparent immobility and centrality within the universe. From this time, independent investigation into the Ptolemaic system became possible. According to Dallal (2010), the use of parameters, sources and calculation methods from different scientific traditions made the Ptolemaic tradition "receptive right from the beginning to the possibility of observational refinement and mathematical restructuring".
Egyptian astronomer Ibn Yunus found fault in Ptolemy's calculations about the planet's movements and their peculiarity in the late 10th century. Ptolemy calculated that Earth's wobble, otherwise known as precession, varied 1 degree every 100 years. Ibn Yunus contradicted this finding by calculating that it was instead 1 degree every 701⁄4 years.
Between 1025 and 1028, Ibn al-Haytham wrote his Al-Shukuk ala Batlamyus (meaning "Doubts on Ptolemy"). While maintaining the physical reality of the geocentric model, he criticized elements of the Ptolemic models. Many astronomers took up the challenge posed in this work, namely to develop alternate models that resolved these difficulties. In 1070, Abu Ubayd al-Juzjani published the Tarik al-Aflak where he discussed the "equant" problem of the Ptolemic model and proposed a solution.[ citation needed ] In Al-Andalus, the anonymous work al-Istidrak ala Batlamyus (meaning "Recapitulation regarding Ptolemy"), included a list of objections to the Ptolemic astronomy.
Nasir al-Din al-Tusi, the creator of the Tusi Couple, also worked heavily to expose the problems present in Ptolemy's work. In 1261, Tusi published his Tadkhira, which contained 16 fundamental problems he found with Ptolemaic astronomy,and by doing this, set off a chain of Islamic scholars that would attempt to solve these problems. Scholars such as Qutb al-Din al-Shirazi, Ibn al-Shatir, and Shams al-Din al-Khafri all worked to produce new models for solving Tusi's 16 Problems, and the models they worked to create would become widely adopted by astronomers for use in their own works.
Abu Rayhan Biruni (b. 973) discussed the possibility of whether the Earth rotated about its own axis and around the Sun, but in his Masudic Canon, he set forth the principles that the Earth is at the center of the universe and that it has no motion of its own.He was aware that if the Earth rotated on its axis, this would be consistent with his astronomical parameters, but he considered this a problem of natural philosophy rather than mathematics.
His contemporary, Abu Sa'id al-Sijzi, accepted that the Earth rotates around its axis.Al-Biruni described an astrolabe invented by Sijzi based on the idea that the earth rotates:
I have seen the astrolabe called Zuraqi invented by Abu Sa'id Sijzi. I liked it very much and praised him a great deal, as it is based on the idea entertained by some to the effect that the motion we see is due to the Earth's movement and not to that of the sky. By my life, it is a problem difficult of solution and refutation. [...] For it is the same whether you take it that the Earth is in motion or the sky. For, in both cases, it does not affect the Astronomical Science. It is just for the physicist to see if it is possible to refute it.
The fact that some people did believe that the earth is moving on its own axis is further confirmed by an Arabic reference work from the 13th century which states:
According to the geometers [or engineers] (muhandisīn), the earth is in constant circular motion, and what appears to be the motion of the heavens is actually due to the motion of the earth and not the stars.
At the Maragha and Samarkand observatories, the Earth's rotation was discussed by al-Kātibī (d. 1277),Tusi (b. 1201) and Qushji (b. 1403). The arguments and evidence used by Tusi and Qushji resemble those used by Copernicus to support the Earth's motion. However, it remains a fact that the Maragha school never made the big leap to heliocentrism.
In the 12th century, non-heliocentric alternatives to the Ptolemaic system were developed by some Islamic astronomers in al-Andalus, following a tradition established by Ibn Bajjah, Ibn Tufail, and Ibn Rushd.
A notable example is Nur ad-Din al-Bitruji, who considered the Ptolemaic model mathematical, and not physical.Al-Bitruji proposed a theory on planetary motion in which he wished to avoid both epicycles and eccentrics. He was unsuccessful in replacing Ptolemy's planetary model, as the numerical predictions of the planetary positions in his configuration were less accurate than those of the Ptolemaic model. One original aspects of al-Bitruji's system is his proposal of a physical cause of celestial motions. He contradicts the Aristotelian idea that there is a specific kind of dynamics for each world, applying instead the same dynamics to the sublunar and the celestial worlds.
In the late thirteenth century, Nasir al-Din al-Tusi created the Tusi couple, as pictured above. Other notable astronomers from the later medieval period include Mu'ayyad al-Din al-'Urdi (c. 1266), Qutb al-Din al Shirazi (c. 1311), Sadr al-Sharia al-Bukhari (c. 1347), Ibn al-Shatir (c. 1375), and Ali al-Qushji (c. 1474).
In the fifteenth century, the Timurid ruler Ulugh Beg of Samarkand established his court as a center of patronage for astronomy. He studied it in his youth, and in 1420 ordered the construction of Ulugh Beg Observatory, which produced a new set of astronomical tables, as well as contributing to other scientific and mathematical advances.
Several major astronomical works were produced in the early 16th century, including ones by 'Abd al-Ali al-Birjandi (d. 1525 or 1526) and Shams al-Din al-Khafri (fl. 1525). However, the vast majority of works written in this and later periods in the history of Islamic sciences are yet to be studied.
Several works of Islamic astronomy were translated to Latin starting from the 12th century.
The work of al-Battani (d. 929), Kitāb az-Zīj ("Book of Astronomical Tables"), was frequently cited by European astronomers and received several reprints, including one with annotations by Regiomontanus.Copernicus, in his book that initiated the Copernican Revolution, the De Revolutionibus Orbium Coelestium , mentioned al-Battani no fewer than 23 times, and also mentions him in the Commentariolus . Tycho Brahe, Riccioli, Kepler, Galileo and others frequently cited him or his observations. His data is still used in geophysics.
Around 1190, Al-Bitruji published an alternative geocentric system to Ptolemy's model. His system spread through most of Europe during the 13th century, with debates and refutations of his ideas continued to the 16th century.In 1217, Michael Scot finished a Latin translation of al-Bitruji's Book of Cosmology (Kitāb al-Hayʾah), which became a valid alternative to Ptolemy's Almagest in scholastic circles. Several European writers, including Albertus Magnus and Roger Bacon, explained it in detail and compared it with Ptolemy's. Copernicus cited his system in the De revolutionibus while discussing theories of the order of the inferior planets.
Some historians maintain that the thought of the Maragheh observatory, in particular the mathematical devices known as the Urdi lemma and the Tusi couple, influenced Renaissance-era European astronomy and thus Copernicus.Copernicus used such devices in the same planetary models as found in Arabic sources. Furthermore, the exact replacement of the equant by two epicycles used by Copernicus in the Commentariolus was found in an earlier work by Ibn al-Shatir (d. c. 1375) of Damascus. Copernicus' lunar and Mercury models are also identical to Ibn al-Shatir's.
While the influence of the criticism of Ptolemy by Averroes on Renaissance thought is clear and explicit, the claim of direct influence of the Maragha school, postulated by Otto E. Neugebauer in 1957, remains an open question.Since the Tusi couple was used by Copernicus in his reformulation of mathematical astronomy, there is a growing consensus that he became aware of this idea in some way. It has been suggested that the idea of the Tusi couple may have arrived in Europe leaving few manuscript traces, since it could have occurred without the translation of any Arabic text into Latin. One possible route of transmission may have been through Byzantine science, which translated some of al-Tusi's works from Arabic into Byzantine Greek. Several Byzantine Greek manuscripts containing the Tusi-couple are still extant in Italy. Other scholars have argued that Copernicus could well have developed these ideas independently of the late Islamic tradition. Copernicus explicitly references several astronomers of the "Islamic Golden Age" (10th to 12th centuries) in De Revolutionibus: Albategnius (Al-Battani), Averroes (Ibn Rushd), Thebit (Thabit Ibn Qurra), Arzachel (Al-Zarqali), and Alpetragius (Al-Bitruji), but he does not show awareness of the existence of any of the later astronomers of the Maragha school.
It has been argued that Copernicus could have independently discovered the Tusi couple or took the idea from Proclus's Commentary on the First Book of Euclid ,which Copernicus cited. Another possible source for Copernicus's knowledge of this mathematical device is the Questiones de Spera of Nicole Oresme, who described how a reciprocating linear motion of a celestial body could be produced by a combination of circular motions similar to those proposed by al-Tusi.
Islamic influence on Chinese astronomy was first recorded during the Song dynasty when a Hui Muslim astronomer named Ma Yize introduced the concept of seven days in a week and made other contributions.
Islamic astronomers were brought to China in order to work on calendar making and astronomy during the Mongol Empire and the succeeding Yuan Dynasty.The Chinese scholar Yeh-lu Chu'tsai accompanied Genghis Khan to Persia in 1210 and studied their calendar for use in the Mongol Empire. Kublai Khan brought Iranians to Beijing to construct an observatory and an institution for astronomical studies.
Several Chinese astronomers worked at the Maragheh observatory, founded by Nasir al-Din al-Tusi in 1259 under the patronage of Hulagu Khan in Persia.One of these Chinese astronomers was Fu Mengchi, or Fu Mezhai. In 1267, the Persian astronomer Jamal ad-Din, who previously worked at Maragha observatory, presented Kublai Khan with seven Persian astronomical instruments, including a terrestrial globe and an armillary sphere, as well as an astronomical almanac, which was later known in China as the Wannian Li ("Ten Thousand Year Calendar" or "Eternal Calendar"). He was known as "Zhamaluding" in China, where, in 1271, he was appointed by Khan as the first director of the Islamic observatory in Beijing, known as the Islamic Astronomical Bureau, which operated alongside the Chinese Astronomical Bureau for four centuries. Islamic astronomy gained a good reputation in China for its theory of planetary latitudes, which did not exist in Chinese astronomy at the time, and for its accurate prediction of eclipses.
Some of the astronomical instruments constructed by the famous Chinese astronomer Guo Shoujing shortly afterwards resemble the style of instrumentation built at Maragheh.In particular, the "simplified instrument" (jianyi) and the large gnomon at the Gaocheng Astronomical Observatory show traces of Islamic influence. While formulating the Shoushili calendar in 1281, Shoujing's work in spherical trigonometry may have also been partially influenced by Islamic mathematics, which was largely accepted at Kublai's court. These possible influences include a pseudo-geometrical method for converting between equatorial and ecliptic coordinates, the systematic use of decimals in the underlying parameters, and the application of cubic interpolation in the calculation of the irregularity in the planetary motions.
Hongwu Emperor (r. 1368-1398) of the Ming Dynasty (1328–1398), in the first year of his reign (1368), conscripted Han and non-Han astrology specialists from the astronomical institutions in Beijing of the former Mongolian Yuan to Nanjing to become officials of the newly established national observatory.
That year, the Ming government summoned for the first time the astronomical officials to come south from the upper capital of Yuan. There were fourteen of them. In order to enhance accuracy in methods of observation and computation, Hongwu Emperor reinforced the adoption of parallel calendar systems, the Han and the Hui. In the following years, the Ming Court appointed several Hui astrologers to hold high positions in the Imperial Observatory. They wrote many books on Islamic astronomy and also manufactured astronomical equipment based on the Islamic system.
The translation of two important works into Chinese was completed in 1383: Zij (1366) and al-Madkhal fi Sina'at Ahkam al-Nujum, Introduction to Astrology (1004).
In 1384, a Chinese astrolabe was made for observing stars based on the instructions for making multi-purposed Islamic equipment. In 1385, the apparatus was installed on a hill in northern Nanjing.
Around 1384, during the Ming Dynasty, Hongwu Emperor ordered the Chinese translation and compilation of Islamic astronomical tables, a task that was carried out by the scholars Mashayihei, a Muslim astronomer, and Wu Bozong, a Chinese scholar-official. These tables came to be known as the Huihui Lifa (Muslim System of Calendrical Astronomy), which was published in China a number of times until the early 18th century,though the Qing Dynasty had officially abandoned the tradition of Chinese-Islamic astronomy in 1659. The Muslim astronomer Yang Guangxian was known for his attacks on the Jesuit's astronomical sciences.
In the early Joseon period, the Islamic calendar served as a basis for calendar reform being more accurate than the existing Chinese-based calendars.A Korean translation of the Huihui Lifa , a text combining Chinese astronomy with Islamic astronomy works of Jamal ad-Din, was studied in Korea under the Joseon Dynasty during the time of Sejong in the fifteenth century. The tradition of Chinese-Islamic astronomy survived in Korea up until the early nineteenth century.
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 degree measurement were performed (al-Ma'mun's arc measurement), solar parameters were established, and detailed observations of the Sun, Moon, and planets were undertaken.
In the tenth 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 950. 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 stars. Sharaf al-Daula also established a similar observatory in Baghdad. 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.
The most influential observatory was however founded by Hulegu Khan during the thirteenth century. Here, Nasir al-Din al-Tusi supervised its technical construction at Maragha. 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.
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 Muhammad ibn Ma'ruf founded a large observatory in Ottoman Constantinople in 1577, which was on the same scale as those in Maragha and Samarkand. The observatory was short-lived however, as opponents of the observatory and prognostication from the heavens prevailed and the observatory was destroyed in 1580.While the Ottoman clergy did not object to the science of astronomy, the observatory was primarily being used for astrology, which they did oppose, and successfully sought its destruction.
As observatory development continued, Islamicate scientists began to pioneer the planetarium. The major difference between a planetarium and an observatory is how the universe is projected. In an observatory, you must look up into the night sky, on the other hand, planetariums allow for universes planets and stars to project at eye-level in a room. Scientist Ibn Firnas, created a planetarium in his home that included artificial storm noises and was completely made of glass. Being the first of its kind, it very similar to what we see for planetariums today.
Our 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. Muslim astronomers of the "Golden Period" made many improvements to instruments already in use before their time, such as adding new scales or details.
Celestial globes 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. The initial blueprint for a portable celestial globe to measure celestial coordinates came from Spanish Muslim astronomer Jabir ibn Aflah (d. 1145). Another skillful Muslim astronomer working on celestial globes was ‘Abd al-Rahman al-Sufi(b. 903), whose treatise describes how to design the constellation images on the globe, as well as how to use the celestial globe. However, it was in Iraq in the 10th century that astronomer Al-Battani was working on celestial globes to record celestial data. This was different because up until then, the traditional use for a celestial globe was as an observational instrument. Al-Battani’s treatise describes in detail the plotting coordinates for 1,022 stars, as well as how the stars should be marked. An armillary sphere had similar applications. 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.
Brass astrolabes were an invention of Late Antiquity. The first Islamic astronomer reported as having built an astrolabe is Muhammad al-Fazari (late 8th century).Astrolabes were popular in the Islamic world during the "Golden Age", chiefly as an aid to finding the qibla. The earliest known example is dated to 927/8 (AH 315).
The device was incredibly useful, and sometime during the 10th century it was brought to Europe from the Muslim world, where it inspired Latin scholars to take up a vested interest in both math and astronomy.Despite how much we know much about the tool, many of the functions of the device have become lost to history. Although it is true that there are many surviving instruction manuals, historians have come to the conclusion that there are more functions of specialized astrolabes that we do not know of. One example of this is an astrolabe created by Nasir al-Din al-Tusi in Aleppo in the year 1328/29 C.E. This particular astrolabe was special and is hailed by historians as the "most sophisticated astrolabe ever made", being known to have five distinct universal uses.
The largest function of the astrolabe is it serves as a portable model of space that can calculate the approximate location of any heavenly body found within the solar system at any point in time, provided the latitude of the observer is accounted for. In order to adjust for latitude, astrolabes often had a secondary plate on top of the first, which the user could swap out to account for their correct latitude.One of the most useful features of the device is that the projection created allows users to calculate and solve mathematical problems graphically which could otherwise be done only by using complex spherical trigonometry, allowing for earlier access to great mathematical feats. In addition to this, use of the astrolabe allowed for ships at sea to calculate their position given that the device is fixed upon a star with a known altitude. Standard astrolabes performed poorly on the ocean, as bumpy waters and aggressive winds made use difficult, so a new iteration of the device, known as a Mariner's astrolabe, was developed to counteract the difficult conditions of the sea.
The instruments were used to read the time of rise of the Sun and fixed stars. al-Zarqali of Andalusia 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 Saphea.
The astrolabe was arguably the most important instrument created and used for astronomical purposes in the medieval period. Its invention in early medieval times required immense study and much trial and error in order to find the right method of which to construct it to where it would work efficiently and consistently, and its invention led to several mathematic advances which came from the problems that arose from using the instrument.The astrolabe’s original purpose was to allow one to find the altitudes of the sun and many visible stars, during the day and night, respectively. However, they have ultimately come to provide great contribution to the progress of mapping the globe, thus resulting in further exploration of the sea, which then resulted in a series of positive events that allowed the world we know today to come to be. The astrolabe has served many purposes over time, and it has shown to be quite a key factor from medieval times to the present.
The astrolabe, as mentioned before, required the use of mathematics, and the development of the instrument incorporated azimuth circles, which opened a series of questions on further mathematical dilemmas.Astrolabes served the purpose of finding the altitude of the sun, which also meant that they provided one the ability to find the direction of Muslim prayer (or the direction of Mecca). Aside from these perhaps more widely known purposes, the astrolabe has led to many other advances as well. One very important advance to note is the great influence it had on navigation, specifically in the marine world. This advancement is incredibly important because the calculation of latitude being made more simple not only allowed for the increase in sea exploration, but it eventually led to the Renaissance revolution, the increase in global trade activity, even the discovery of several of the world’s continents.
Abu Rayhan Biruni designed an instrument he called "Box of the Moon", which was a mechanical lunisolar calendar, employing a gear train and eight gear-wheels.This was an early example of a fixed-wired knowledge processing machine. This work of Al Biruni uses the same gear trains preserved in a 6th century Byzantine portable sundial.
Muslims made several important improvements[ which? ] to the theory and construction of sundials, which they inherited from their Indian and Greek 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 fourteenth century by the muwaqqit (timekeeper) of the Umayyad Mosque in Damascus, ibn al-Shatir.
Several forms of quadrants 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.Abu Bakr ibn al-Sarah al-Hamawi (d. 1329) was a Syrian astronomer that invented a quadrant called “al-muqantarat al-yusra”. He devoted his time to writing several books on his accomplishments and advancements with quadrants and geometrical problems. His works on quadrants include Treatise on Operations with the Hidden Quadrant and Rare Pearls on Operations with the Circle for Finding Sines. These instruments could measure the altitude between a celestial object and the horizon. However, as Muslim astronomers used them, they began to find other ways to use them. For example, the mural quadrant, for recording the angles of planets and celestial bodies. Or the universal quadrant, for latitude solving astronomical problems. The horary quadrant, for finding the time of day with the sun. The almucantar quadrant, which was developed from the astrolabe.
Planetary equatoria were probably made by ancient Greeks, although no findings nor descriptions have been preserved from that period. In his comment on Ptolemy's Handy Tables, 4th century mathematician Theon of Alexandria introduced some diagrams to geometrically compute the position of the planets based on Ptolemy's epicyclical theory. The first description of the construction of a solar (as opposed to planetary) equatorium is contained in Proclus's fifth-century work Hypotyposis,where he gives instructions on how to construct one in wood or bronze.
The earliest known description of a planetary equatorium is contained in early 11th century treatise by Ibn al‐Samḥ, preserved only as a 13th century Castillian translation contained in the Libros del saber de astronomia (Books of the knowledge of astronomy); the same book contains also a 1080/1081 treatise on the equatorium by al-Zarqālī.
There are examples of cosmological imagery throughout many forms of Islamic art, whether that be manuscripts, ornately crafted astrological tools, or palace frescoes, just to name a few. Islamic art maintains the capability to reach every class and level of society.
Within Islamic cosmological doctrines and the Islamic study of astronomy, such as the Encyclopedia of the Brethren of Purity (alternatively called The Rasa'il of the Ikhwan al-Safa) there is a heavy emphasis by medieval scholars on the importance of the study of the heavens. This study of the heavens has translated into artistic representations of the universe and astrological concepts.There are many themes under which Islamic astrological art falls under, such as religious, political, and cultural contexts. It is posited by scholars that there are actually three waves or traditions of cosmological imagery, Western, Byzantine, and Islamic. The Islamic world gleaned inspiration from Greek, Iranian, and Indian methods in order to procure a unique representation of the stars and the universe.
A place like Quasyr' Amra, which was used as a rural Umayyad palace and bath complex, coveys the way astrology and the cosmos have weaved their way into architectural design. During the time of its use, one could be resting in the bathhouse and gaze at the frescoed dome that would almost reveal a sacred and cosmic nature. Aside from the other frescoes of the complex which heavily focused on al-Walid, the bath dome was decorated in the Islamic zodiac and celestial designs.It would have almost been as if the room was suspended in space. In their encyclopedia, the Ikhwan al' Safa describe the Sun to have been placed at the center of the universe by God and all other celestial bodies orbit around it in spheres. As a result, it would be as if whoever was sitting underneath this fresco would have been at the center of the universe, reminded of their power and position. A place like Qusayr' Amra represents the way astrological art and images interacted with Islamic elites and those who maintained caliphal authority.
The Islamic zodiac and astrological visuals have also been present in metalwork. Ewers depicting the twelve zodiac symbols exist in order to emphasize elite craftsmanship and carry blessings such as one example now at the Metropolitan Museum of Art.Coinage also carried zodiac imagery that bears the sole purpose of representing the month in which the coin was minted. As a result, astrological symbols could have been used as both decoration, and a means to communicate symbolic meanings or specific information.
An astrolabe is an ancient astronomical instrument that was a handheld model of the universe. Its various functions also make it an elaborate inclinometer and an analogue calculation device capable of working out several kinds of problems in astronomy. Historically used by astronomers, it is able to measure the altitude above the horizon of a celestial body, day or night; it can be used to identify stars or planets, to determine local latitude given local time, to survey, or to triangulate. It was used in classical antiquity, the Islamic Golden Age, the European Middle Ages and the Age of Discovery for all these purposes.
Heliocentrism is the astronomical model in which the Earth and planets revolve around the Sun at the center of the Universe. Historically, heliocentrism was opposed to geocentrism, which placed the Earth at the center. The notion that the Earth revolves around the Sun had been proposed as early as the 3rd century BC by Aristarchus of Samos, but at least in medieval Europe, Aristarchus' heliocentrism attracted little attention—possibly because of the loss of scientific works of the Hellenistic period.
Abū Isḥāq Ibrāhīm ibn Yaḥyā al-Naqqāsh al-Zarqālī al-Tujibi ; also known as Al-Zarkali or Ibn Zarqala (1029–1087), was an Arab Muslim instrument maker, astrologer, and the most important astronomer from the western part of the Islamic world.
Abū al-ʿAbbās Aḥmad ibn Muḥammad ibn Kathīr al-Farghānī, also known as Alfraganus in the West, was an astronomer in the Abbasid court in Baghdad, and one of the most famous astronomers in the 9th century. Al-Farghani composed several works on astronomy and astronomical equipment that were widely distributed in Arabic and Latin and were influential to many scientists. His best known work, Kitāb fī Jawāmiʿ ʿIlm al-Nujūmi, was an extensive summary of Ptolemy's Almagest containing revised experimental data. Among those influenced by al-Farghani's works were Copernicus, who is said to have used al-Farghani’s calculation of the diameter of the Earth in his own calculations, and Christopher Columbus, who used the same calculation for his voyages to America. In addition to making substantial contributions to astronomy, al-Farghani also worked as an engineer, supervising construction projects on rivers in Cairo, Egypt. The lunar crater Alfraganus is named after him.
Taqi ad-Din Muhammad ibn Ma'ruf ash-Shami al-Asadi was an Ottoman polymath active in Cairo and Istanbul. He was the author of more than ninety books on a wide variety of subjects, including astronomy, clocks, engineering, mathematics, mechanics, optics and natural philosophy.
The Constantinople observatory of Taqi ad-Din, founded in Constantinople by Taqi ad-Din Muhammad ibn Ma'ruf in 1577, was one of the largest astronomical observatories in medieval world. However, it only existed for a few years and was destroyed in 1580.
ʿAbu al-Ḥasan Alāʾ al‐Dīn ʿAlī ibn Ibrāhīm al-Ansari known as Ibn al-Shatir or Ibn ash-Shatir was an Arab astronomer, mathematician and engineer. He worked as muwaqqit in the Umayyad Mosque in Damascus and constructed a sundial for its minaret in 1371/72.
Al-Urdi was a medieval Syrian astronomer and geometer.
The Tusi couple is a mathematical device in which a small circle rotates inside a larger circle twice the diameter of the smaller circle. Rotations of the circles cause a point on the circumference of the smaller circle to oscillate back and forth in linear motion along a diameter of the larger circle. The Tusi couple is a 2-cusped hypocycloid.
Islamic cosmology is the cosmology of Islamic societies. It is mainly derived from the Qur'an, Hadith, Sunnah, and current Islamic as well as other pre-Islamic sources. The Qur'an itself mentions seven heavens.
Some medieval Muslims took a keen interest in the study of astrology, despite the Islamic prohibitions: partly because they considered the celestial bodies to be essential, partly because the dwellers of desert-regions often travelled at night, and relied upon knowledge of the constellations for guidance in their journeys. After the advent of Islam, the Muslims needed to determine the time of the prayers, the direction of the Kaaba, and the correct orientation of the mosque, all of which helped give a religious impetus to the study of astronomy and contributed towards the belief that the heavenly bodies were influential upon terrestrial affairs as well as the human condition. The science dealing with such influences was termed astrology, a discipline contained within the field of astronomy. The principles of these studies were rooted in Arabian, Persian, Babylonian, Hellenistic and Indian traditions and both were developed by the Arabs following their establishment of a magnificent observatory and library of astronomical and astrological texts at Baghdad in the 8th century.
Maragheh observatory was an astronomical observatory established in 1259 CE under the patronage of the Ilkhanid Hulagu and the directorship of Nasir al-Din al-Tusi, a Persian scientist and astronomer. Located in the heights west of Maragheh, which is today situated in the East Azerbaijan Province of Iran, it was once considered "the most advanced scientific institution in the Eurasian world".
Copernican heliocentrism is the name given to the astronomical model developed by Nicolaus Copernicus and published in 1543. This model positioned the Sun at the center of the Universe, motionless, with Earth and the other planets orbiting around it in circular paths, modified by epicycles, and at uniform speeds. The Copernican model displaced the geocentric model of Ptolemy that had prevailed for centuries, which had placed Earth at the center of the Universe. Copernican heliocentrism is often regarded as the launching point to modern astronomy and the Scientific Revolution.
A zij is an Islamic astronomical book that tabulates parameters used for astronomical calculations of the positions of the Sun, Moon, stars, and planets.
Abd Ali ibn Muhammad ibn Husayn Birjandi was a prominent 16th-century Persian astronomer, mathematician and physicist who lived in Birjand.
Medieval Islamic geography and cartography refer to the study of geography and cartography in the Muslim world during the Islamic Golden Age. Muslim scholars made advances to the map-making traditions of earlier cultures, particularly the Hellenistic geographers Ptolemy and Marinus of Tyre, combined with what explorers and merchants learned in their travels across the Old World (Afro-Eurasia). Islamic geography had three major fields: exploration and navigation, physical geography, and cartography and mathematical geography. Islamic geography reached its apex with Muhammad al-Idrisi in the 12th century.
Ala al-Dīn Ali ibn Muhammed, known as Ali Qushji was a Timurid theologian, jurist, astronomer, mathematician and physicist, who settled in the Ottoman Empire some time before 1472. As a disciple of Ulugh Beg, he is best known for the development of astronomical physics independent from natural philosophy, and for providing empirical evidence for the Earth's rotation in his treatise, Concerning the Supposed Dependence of Astronomy upon Philosophy. In addition to his contributions to Ulugh Beg's famous work Zij-i-Sultani and to the founding of Sahn-ı Seman Medrese, one of the first centers for the study of various traditional Islamic sciences in the Ottoman caliphate, Ali Kuşçu was also the author of several scientific works and textbooks on astronomy.
Egyptian astronomy begins in prehistoric times, in the Predynastic Period. In the 5th millennium BCE, the stone circles at Nabta Playa may have made use of astronomical alignments. By the time the historical Dynastic Period began in the 3rd millennium BCE, the 365 day period of the Egyptian calendar was already in use, and the observation of stars was important in determining the annual flooding of the Nile.
Muhammad ibn Muhammad ibn al-Hasan al-Tūsī, better known as Nasir al-Din al-Tusi, was a Persian polymath, architect, philosopher, physician, scientist, and theologian. Nasir al-Din al-Tusi was a well published author, writing on subjects of math, engineering, prose, and mysticism. Additionally, al-Tusi made several scientific advancements. In astronomy, al-Tusi created very accurate tables of planetary motion, an updated planetary model, and critiques of Ptolemaic astronomy. He also made strides in logic, mathematics but especially trigonometry, biology, and chemistry. Nasir al-Din al-Tusi left behind a great legacy as well. Some consider Tusi one of the greatest scientists of medieval Islam, since he is often considered the creator of trigonometry as a mathematical discipline in its own right. The Muslim scholar Ibn Khaldun (1332–1406) considered Tusi to be the greatest of the later Persian scholars. There is also reason to believe that he may have influenced Copernican heliocentrism.
Shams al-Din Muhammad b. Ahmad al-Khafri al-Kashi, known as Khafri, was an Iranian religious scholar and astronomer at the beginning of the Safavid dynasty. Before the arrival of Sheikh Baha'i in Iran, he was appointed as the major Shia jurist in the Safavid court. He was born in the city of Ḵafr, south east of Firuzābād in the region of Fārs. His exact date of birth is unknown but historical accounts estimate the date of his birth to be around the 1480s. He wrote on philosophy, religion, and astronomy, with the latter including a commentary on al-Tusi and critiques of al-Shirazi. Al-Khafri wrote works on theology and astronomy, indicating that Islamic scholars in his time and place saw no contradictions between Islam and science.
It was on this occasion [in the eighth century] that the Arabs first became acquainted with a scientific system of astronomy. They learned from Brahmagupta earlier than from Ptolemy.
And it so happens that the particular intellectual activity that inspired these materials is related to the religious obligation to pray at specific times. The material presented here makes nonsense of the popular modern notion that religion inevitably impedes scientific progress, for in this case, the requirements of the former actually inspired the progress of the latter for centuries.