A Brief History of Observatories in the Islamic World

Review of Religions: September 200146 An observatory is a structure built for the purpose of astronomical observation. Observations date back to many of the earliest civilizations: it is thought that Stonehenge in England and the Great Pyramid of Cheops were also observatories. In Islam this institution flowered under Caliph al- Mamun (786-833 CE) who laid the foundation of the first observatory in Islam. Astronomical observations were made under his patronage at Shamsiya, near Baghdad and at Mount Qasiyun, near Damascus. Shamasiya was supplied with a building which served as a residence and place of work for its astronomers including Sanad ibn Ali who was asked to build astronomical instruments. Yahya ibn Abi Mansur and al Abbas al-Jawhari were the two other astronomers employed in this o b s e r v a t o r y. Both these scientists took part in the astronomical observations organized at Baghdad 829-30 and Damascus 832-33. The Shamasiya observatory was part of the Baytul Hikma (House of Wisdom) which was also established by al-Mamun in Baghdad. This was called Khizana Kutub al-Hikma (Library of Wisdom) as it consisted of a library which carried out trans- lations of many scientific and philosophical works. Regular weekly meetings of translators and scientists were held at Baytul Hikma, in this respect it was an academy like Plato’s. The famous mathematician al- Khawarizmi (780-850) was at one time librarian of this science institute. A Brief History of Observatories in the Islamic World by Zakaria Virk – Kingston, Canada ‘The Christians in Spain suffered a humiliating Jehad under the superior military power of the Islamic Moorish caliphate. It was the worst of time for Europe. The glories of Rome were dust. The science of the Greeks was all but forgotten. Meanwhile, Arabic culture was at its zenith. Arabic astronomy had picked up the torch of Greek science and developed a well-integrated celestial system, elements of which are still used by astronomers today.’ (Sky & Telescope, USA. p.38, Feb. 2000) Review of Religions: September 2001 A Brief History of Observatories in the Islamic Worrld 47 He was one of the first to compute astronomical tables. It may be of interest that some people were sent by al-Mamun to Byzantine to purchase Greek scientific manuscripts. Al-Biruni informs us that two solstice observations were made at Shamasiyya by Yahya ibn Mansur in the year 828 CE in which al- Khawarizmi was also present. Two more observations were made using an armillary sphere the next year and compared with the previous year. Work lasted here for a year and a half. Ibn Khalaf al-Marwrudhi was an instrument designer who made an astrolabe (an instrument used for measuring the altitude of a heavenly body and replaced by the Sextant in the 18th century). An azimuthal quadrant made in Haran was used in Maragha Observatory for the measurement of azimuths, and elevations. Mount Qasiyun Observatory Al-Mamun ordered the construction of an observatory at Mount Qasiyun in 830 or 831. Khalid was an important astronomer here who made an observation of a certain star in the constellation Leo in the presence of two scientists Sanad and al-Abbas. Khalid was in fact the mutawalli (supervisor). Ali ibn Isa al-Ustarlabi (d.832) was another instrument maker here who wrote a treatise on the astrolabe. Al-Mamun died on 10th August 833 (218 AH) and all activity came to an end. Al-Biruni says that a marble mural quadrant was used at Qasiyun that had an inner radius of five metres, and had an accessory part sliding over the arc. This part had a hole through which one looked at the sun. A l – M a m u n ’s astronomers made observations of the sun and moon only, and some investigations of the planets and the fixed stars for which a list of star positions was prepared. The work at Shamasiya and Qasiyun resulted in the discovery of the movement of the solar apogee (farthest point), while their equinox (when Sun shines down directly on the equator of a planet) observations led to a pretty exact value of the length of the solar year. According to Umar al-Khayyam the reason for these observations was to establish a solar calendar for Nawruz, New Years day of the Persian calendar. The emphasis on the solar and lunar observations was to calculate the eclipses. Tables of planetary motions were constructed and presented in a book called Zij Mumtahan, (tested tables) A Brief History of Observatories in the Islamic Worrld Review of Religions: September 200148 written by Yahya ibn Abi Masnur. It was also called Zij Shamasiya. All of the astronomers of al-Mamun produced a Zij (astronomical table) which is indicative of the fact that it must have been one of the primary objectives for setting up the observatories. One of the important astronomical activities undertaken by order of al- Mamun was the determination of the Qibla. The key to such determination was the geographic location of Mecca. Al-Mamun had the latitude and longitude of Mecca determined through observations of lunar eclipses made simultaneously in Baghdad and Mecca. The surveyors measured the distance between these two cities. A party of astronomers and expert artisans, which included carpenters and brass-smiths, went to Sinjar with instruments to measure the altitude of the sun. Three surveyors Khalid al- Maurudhi, Ali ibn Isa and Ahmad al Dharra measured the length of a terrestrial degree to ascertain the value of one stadium. The results of this expedition were transmitted by Sanad, and the expedition paid for by the Banu Musa brothers. It was thus the first systematic geodetic expedition of its kind. A large map of the world was drawn for the Caliph, who ordered two degrees measure- ment to be made to determine the size of the earth that came out to 20,400 miles and a diameter of 6,500 miles. Al-Mamun was conversant with astronomy and had a genuine interest in its issues as the following incident will show. In the course of an expedition against Byzantium, al- Mamun noticed that the high mountain by which they were passing had a commanding view of the sea. He ordered Sanad ibn Ali to climb to the top of the hill and measure from it the angle of depression of the horizon at sunset. This was done and the dimension of the earth calculated from it. Al-Biruni says in his book Qanun al-Masudi that he himself used this method on a hill in District Jehlum in Pakistan. The Banu Musa brothers (Muhammad, Ahmad & Hasan) made a series of observations after the demise of al-Mamun. The first two brothers directed the Sinjar and Kufa geodetic measurements. Muhammad died in 259 AH, about 40 years after the death of al-Mamun. A l – B i r u n i reported their astronomical obser- vations that took place from 858-869 CE. Ibn Yunus mentions six observations, some of them the same as al-Biruni. Their fixed stars observations and measurements of the maximum and minimum altitudes of Review of Religions: September 2001 A Brief History of Observatories in the Islamic Worrld 49 the sun took place in Baghdad from their house by the Tigris river close to the city gate called Bab al-Taq. They made arrangements for simultaneous observations of a lunar eclipse in Samarra and Nishabur. Habash al-Hasib (864-874) was an outstanding astronomer of al-Mamun who made observations for ten years and compiled three astronomical tables. He observed the solar eclipse of 829 CE and determined the time by the Sun’s altitude. Al-Farghani was one of the greatest astronomers employed by al-Mamun. He wrote a book Kitab fee Harakat a l – S a m a w i y a (Elements of Astronomy) which exerted a great influence on European astronomy. This was translated by Gerard of Cremona and first printed in 1493. Abu Hanifa al-Dinawari (815-895) was a physician and astronomer who lived in Dinawar. He authored a book Kitab al-Rasad in which he recorded his observations of the year 849-850 CE made from the top of a house in Isphahan. He also owned a private observatory (Sahib al-Rasad) in his hometown. Muhammad ibn Jabir al-Battani (858- 929) is considered the greatest astronomer of Islam. He had a private observatory at al-Raqqa (Syria) where he made his observations for forty years (887-918). His tables known as Zij is called Zij al-Sabi. They contain a catalogue of fixed stars for the year 880-881. He proved the possibility of annular eclipses of the sun. His astronomical tables were edited by Italian scholar C.A. Nallino and published in 1903 in Arabic and Latin. He used the following instruments: 1. Astrolabe 2. Gnomon for precise observations 3. Sun clocks 4. An armillary sphere 5. Parallactic rulers 6. Mural quadrant 7. An alidade. It is assumed that these instruments were of larger dimensions required for the measurements of the obliquity of the ecliptic. AL- MA M U N H A D T H E L AT I T U D E A N D L O N G I T U D E O F ME C C A DETERMINED THROUGH OBSERVATIONS OF LUNAR ECLIPSES MADE SIMULTANEOUSLY IN BAGHDAD AND MECCA. THE SURVEYORS MEASURED THE DISTANCE BETWEEN THESE TWO CITIES. A Brief History of Observatories in the Islamic Worrld Review of Religions: September 200150 His famous book was Kitab al-Zij, an astronomical treatise with tables, translated into Latin by Plato of Tivoli in the 12th century under the title “De Motu Stellaru m”. It was first published in Nuremberg in 1537. He discovered the secular acceleration of the Moon. In 1773 The Paris Academy of Sciences awarded a prize to Edmond Halley for giving an explanation of the Moon’s secular acceleration by examining solar and lunar eclipse records made by al- Battani. (Sky & Telescope magazine, October 2000, USA, page 60). Sulaiman ibn Isma made his observations in Balkh to determine the obliquity of the ecliptic in the years 888-890. He used a mural quadrant and an alidade. He made some Equinox (day when night and day are of equal length) and Solstice (time of year when the Sun reaches its farthest North or South point, resulting in the longest or shortest day) observations also. Mansur ibn Talha made various observations of the obliquity in Khurasan. Al-Biruni refers to his observations for determining geographical latitudes as well as his eclipse observations for measurements of the longitude. He made comparisons of the longitudes of cities in Khurasan with those of Baghdad and Mecca. He improved the value for the latitude of Mecca found in the time of al-Mamun. Ibn Amajur: Abu al-Qasim ibn Amajur and his son Abul Hassan Ali were among the greatest astronomers of Islam. Father, son and their emancipated slave Muflih, made extensive observations between 885- 933 and produced numerous Tables as recorded by Ibn Yunus( Sarton, page 630). They made their observations in Shiraz and Baghdad, which included fixed stars, as well as lunar, solar and planetary observations. His Zij al- M i rr i k h (tables of Mars) are very famous. It is said that they observed the image of the sun in the water. Abdul Rahman al-Sufi (903-986) was famous for his work on fixed stars. He measured the obliquity of the ecliptic in Shiraz at the winter & summer solstices in the year 969-970 by the order of his friend Buwayhid ruler Adud al-Dawla (936-983). Al-Biruni mentions an observation of the vernal equinox and one of autumnal equinox made by al-Sufi in Shiraz. His main work with illustrations is ‘Book of the Fixed Stars’ (Kitab al-kawakib al- sabitha al-Musawar) which is considered one of the three masterpieces of Islamic astronomy, Review of Religions: September 2001 A Brief History of Observatories in the Islamic Worrld 51 the other two being Ibn Yunus and Ulugh Bey. (Sarton, page 666). Ibn al-Alam (d.985) conducted most of his observations in Baghdad. The positions of Mars are more accurate in his tables than in any other; his Zij received much favor during the next two centuries. Abul Wafa al-Buzjani (940-997), a distinguished mathematician and astronomer, states in his al-Majisti that he made many observations for the determination of the obliquity of the ecliptic at Bab al- Tibn in Baghdad. Al-Biruni was apparently in contact with Abul Wafa for they made arrangements to observe the lunar eclipse of 997 and compare notes. Abul Wafa observed it in Baghdad while al-Biruni in Khawarizm. The difference in local time was found to be one hour. Sharaf al-Dawla Observatory Sharf al-Dawla son of Adud al-Dawla (982-989) built an observatory in the garden of his palace in Baghdad. He ordered the observations of the seven planets in 988 and al-Kuhi was vested with this work. A building was constructed for this purpose in his garden and had a director. Al-Kuhi designed the instruments for this Bayt al-Rasad, some of which were made by the inventor and instrument maker Abu Hameed Al-Saighani (d.990). The observations were made in the presence of judges, scientists, and scholars. Al-Biruni says that al-Kuhi constructed a spherical building in Baghdad whose floor was in the form of a section of a sphere with a radius of 12.5 metres. The centre of this sphere was located at the hole at the top of the building; solar rays entered from this aperture and traced the daily trajectories. One solstice observation was also made. Abu Mahmud Al Khujandi (d.1000) made an important measurement of the obliquity of the ecliptic in 994 at Jabal Tabruk, near the city of Ray in Iran. The instrument constructed for this purpose surpassed all previous ones in size; it consisted of a sixty- degree meridian arc and was called al Suds al-Fakhri (named after his partron Fakhar al-Dawla). Suds mean the sixth part (of a circle). It had a radius of about 20 metres. This was al-Khudanji’s invention, and with this instrument, degrees, minutes and seconds could be read. Each degree was subdivided into 360 equal parts, and each ten-second portion was distinguished on the scale. The arc, which was constructed between two walls, was faced with wood, and on this wooden surface were sheets of c o p p e r. He had many outstanding astronomers of his time assisting him in this work. A Brief History of Observatories in the Islamic Worrld Review of Religions: September 200152 By the end of tenth century, the observatory was a specialised institution with fixed locations, devoted to research in astronomy. It contained many instruments and scientific staff. There was an emphasis on building larg e – s c a l e instruments. Administratively it was well organized. It also had a director and was given some kind of legal status. The program of work included observations of the planets, as well as those of the sun and moon, and the compilation of new astronomical tables. An institution of this magnitude could not function without royal patronage; hence the observatory was a royal institution. Other observatories built alongside Sharf al-Dawla were Adud al-Dawla in Shiraz and Fakr al-Daula in Ray, Iran. Maslama al-Majriti (d.1007) was a renowned mathematician and astronomer of Islamic Spain. He edited and corrected the astronomical tables of al-Khawrizmi. He wrote a treatise on the astrolabe that was translated by John of Seville. Michael Scot translated his book on astronomy Kitab al-Haya. Maslama created a school of astronomers consisting of his students ( like al-Karmani, and ibn-Samh) marking the beginning of science as an organized activity in Islamic Spain. All his students commented on the use of the astrolabe, and Zij al-Sindhind. Abu Rehan Al-Biruni (973-1048) was a contemporary of Ibn Sena. He built several observation posts for the measurement of the obliquity of the ecliptic as well as the determination of geographic locations. The earliest observation he made in 990 was in Khawarizm when he was a youth. He repeated measurements of latitude in several cities. He composed an astronomical encyclopedia (Q a n u n al-Masudi fee Haye wal Najum) which contains a collection of 23 observations of equinoxes beginning with Ptolemy, and ending with observations he made himself. A l – Biruni went through many ordeals while doing investigations of the latitude; so much so that he compared this to ordeals of Noah(as) and Lot(as), and prayed that he may follow them in rank in meriting Allah’s mercy. The knowledge of geographical locations of cities was important to determine the direction of Qibla and also for revisions of astronomical tables. He mentioned values of longitude and latitude of Mecca with fractions smaller than a degree. To obtain this he used sizeable instruments. Astronomical tables had another u t i l i t y, i.e. determination of the beginning and end of Ramadhan, though actual observation of the new Review of Religions: September 2001 A Brief History of Observatories in the Islamic Worrld 53 moon were equally important. This indicates that religious needs promoted the study of astronomy in Islamic countries. His writings indicate that he accepted the possibility that the Sun rather than the Earth was the centre of the solar system. He suggested that the earth revolved around the Sun and on its axis, and that the axis is tilted. He calculated the circumference of the earth to be 24757.92 miles while the current figure is 24873.75 miles. He calculated the radius of the earth to be 3938.75 miles while the current figure is 3958.78 miles. (Review of Religions, July 1998) Cairo Observatory Abul Hassan Ali Ibn Yunus, one of the greatest Muslim astronomers, author of the Hakimi Tables was a resident of Cairo, where the Fatimid caliph al- Hakim bi-Amrillah (996-1021) built an observatory for him. It was located on Mount Muqattam, near Cairo and was part of the Darul Hikma (Hall of Science – 1005- 1171) founded by al- Hakim. Cairo observatory (Rasad al- Hakimi) which was part of the Hall of Science, was one of the most famous in the history of Islam. Names of astronomers who worked here are recorded in history. It is said that the observatory ceased operation after the death of Ibn Yunus. A copper instrument resembling an astrolabe and resting on two pillars was used for making observations. It contained twelve signs of the zodiac and was three spans in length. Ibn Khaldun (1332-1406) says that al- Hakim was guided by astrology in his decision making of state affairs. He used to ride his donkey and go to Mount Muqattam for prayers, and according to some, for spiritual contact with the stars. (Tarikh, vol. 4 pp.60-61) Al-Hakim’s treatment of the famous scientist, physicist, and astronomer, ibn al-Haisham (965-1039) and his court physician Ali Ibn Ridwan (d.1061) indicated he was unpre- dictable. One solar and three lunar eclipses were observed from the mosque of Abu Jafar al-Maghribi. Ibn Yunus made an observation from his grandfather’s house, and still another from the roof of the old mosque, Al- Jami al-Atiq in Cairo. His house was in the Fustat quarter of old Cairo, to the west of Qarafa. He determined the latitude of this place many times. He is said to have used portable instruments. In one instance he used an instrument in measuring the obliquity of the ecliptic, belonging to al-Aziz, father of al-Hakim. His astronomical tables contained obser- vations of eclipses and improved the values of astronomical constants. His A Brief History of Observatories in the Islamic Worrld Review of Religions: September 200154 tables were printed in Arabic and translated into French. He solved many problems of spherical astro- nomy. Hamadan Observatory Abu Ali Sena convinced Ala al- Dawla, Ameer of Hamadan, that there were deficiencies in the ephemeredes (Taqweem) based on old observations. The Ameer agreed with Ibn Sena to build an observatory in Hamadan in 1023 for observations of the planets (K a w a k i b). Ibn Sena assigned his pupil and biographer al-Juzjani to prepare necessary equipment and employ instrument makers. Ibn Sena spent eight year making observations including of Venus. It is said that measurements of azimuths (east to west) and altitudes (up and down) were carried out with a certain device that embodied the principles of a micrometer. This was installed in the newly built observatory. Georg e Sarton has described him as, ‘the most famous scientist of Islam, and one of the most famous of all races, places and times.’ (page 709, Sarton). Malikshah Observatory This was the first Islamic observatory that functioned as an institution for 20 years. Malikshah was the Saljuq Sultan (1072-1092) who founded this observatory in the eleventh century. The Madrasa system was established during his reign by his vizier Nizam al-Mulk. A group of outstanding astronomers, Umar al-Khayam, al- Asfizari, and ibn Naneeb were invited for its foundation. It functioned until the Sultan’s death. The construction work was supervised by Muhammad al-Bayhaqi, while al-Mamuri was assigned to make instruments. There were eight scientists employed by this institution. Umar Khayam (1048- 1123) produced al-Zij Malikshah probably during the operation of this observatory. It survived its founder for only a short while. He was one of the greatest mathematicians of mediaeval times who was also an eminent astronomer and poet. In 1074 Jalal al-Din Malikshah called him to the new observatory of Isphahan to reform the old Persian calendar. His calendar was called a l – Tarikh al- AS T R O N O M I C A L TA B L E S H A D A N O T H E R U T I L I T Y, I.E. DETERMINATION OF THE BEGINNING AND END OF RAMADHAN, THOUGH ACTUAL OBSERVATION OF THE NEW MOON WERE EQUALLY IMPORTANT. THIS INDICATES THAT RELIGIOUS NEEDS PROMOTED THE STUDY OF ASTRONOMY IN ISLAMIC COUNTRIES. Review of Religions: September 2001 A Brief History of Observatories in the Islamic Worrld 55 Jalali, its era was 16th March 1079. The calendar is very accurate, more accurate than the Gregorian calendar. Al-Afzal Observatory It took from 1120 to 1125 to build this observatory in Cairo. Solar observations were made here. T h e Fatimid Caliph al-Amir Biahkamaalh ( 11 0 1 – 1130) was the ruler of Egypt at that time. Two of his viziers took personal interest in its foundation, al- Afzal al-Jamali, and al Mamun al- Bataihi. Among the famous astro- nomers who worked here were ibn al- Halabi, ibn al-Hayshami, and Sahlun who received monthly allowances from the Caliph. Among the instruments was a ring of about five meters diameter, and an alidade made of copper. All work came to an end upon the death of al-Bataihi in 1125. It should be noted that taqweem contains annual information on the daily positions of the planets, their conjunc- tions and oppositions, and information on solar and lunar eclipses. T h e observatory was also called Observatory Mosque ( Masjid al Rasad al Juyushi) as it was later housed in a mosque. The observatory was demolished due to personal jealousies. Abd al- Rahman al-Khazini was the author of al-Zij al Sanjari, tables giving positions of the stars for the year 1135-36. He observed and calculated positions for all planets as well as the sun and the moon at conjunctions and eclipses. He was in possession of good instruments so he could measure the obliquity of the ecliptic in Isfahan. Tower of Seville, (Spain) Observatory It is said that the famous Spanish astronomer Jabir ibn Aflah used the minaret of the Jami mosque in Seville for making observations. This was in fact the first observatory in Europe. Overlooking the city of Seville, it is now called La Giralda Tower. The construction of the minaret of the mosque started in 1172 and was completed in 1197. Jabir criticized Ptolemy violently in his book Islah a l – M a j i s t i on many astronomical matters. He placed Venus and Mercury above the Sun as opposed to P t o l e m y. His book Kitab al-Haia (Book of Astronomy) was translated by Michael Scot (d.1235) as De Astronomica Libri IX, printed in Nuremberg in 1534. A Jewish scholar from Marseille Samuel ben Juda translated a treatise written by Abu Abdullah Muhamad ibn Muaz of Seville on the total solar eclipse that occurred in 1079. (Impact of trans- lations on the West, page 119). Qazi Saeed al-Andalusi (1029-16th A Brief History of Observatories in the Islamic Worrld Review of Religions: September 200156 June 1070) was a historian of science and an astronomer who flourished in Toledo. Observations made by him and his fellow astronomers were very valuable to al-Zarqali. Abu Ibrahim Al-Zarqali al-Naqqash (1029-1087) was a Spanish astronomer and instrument maker who lived in Cordoba. He was the best observer of his time, who made his observations in Toledo in 1061 and 1080. His influence on medieval European astronomers was considerable; his Toledan tables formed the basis of later work. These tables were mainly based on his own observations, but also upon those directed by Saeed al- Andulasi (1029-1070). Many Muslim and Jewish astronomers also participated in their preparation. Al- Zarqali (Arzachel) was an illiterate coppersmith who was employed by astronomers to make instruments. He was so successful in his art that he started studying astronomy. Soon he became a prominent member of the group of scientists engaged in preparing Toledan tables. He invented an improved astrolabe called Safiha that is a universal instrument for planetary observations. He was the first to prove explicitly the motion of the solar apogee with reference to the stars; according to his measurements it amounted to 12.04” per year (the real value being 11.8”). (Sarton 758). Ibn Bajja (d.1139) made an observation from the roof of his house and saw two specks on the surface of the sun. His calculations corre- sponded with those of Mercury and Venus, he concluded that these two spots must be these two planets. Though he was not a professional a s t r o n o m e r, it appears that his housetop was equipped with certain instruments to make observations. Sooted glass may have been used to look at the sun. Morroco (Fes) Obervatory The observatory in the city of Fes, in Morroco, was called Burj al-Kawakib (Tower of Stars). The purpose of its foundation in the 12th century was observations of the new moon. It remained operational for several centuries. Noor al-Din Ishaq al-Bitruji (d.1204-Albetragius) was born in Morroco, but lived mostly in Seville. He did not trust the human senses given the distance between the observer and the spheres. His astronomical system exerted a deep influence on European scholars up to the time of Copernicus who cited his system in his book D i e R e v o l u t i o n i b u s. Roger Bacon expounded his system in detail discussing his theory of tides in his work Opus Majus. Maragha Observatory When Helagu Khan captured Alamut Review of Religions: September 2001 A Brief History of Observatories in the Islamic Worrld 57 in Syria in 1256, many astronomical instruments were found in the mountain fort. Among these were, a celestial globe (dhat al kursi) , armillary sphere, a half astrolabe (nisfi), a parallactic ruler, and Shua. Nasir al-Din al-Tusi (1201-74) is supposed to have worked there. Maragha was one of the most famous Islamic observatories built in the thirteenth century in Maragha, a city of Azerbaijan, Northwest of modern Iran. Its foundations were later excavated by Russian archaeologists. Al-Tusi suggested to Helagu Khan to build this observatory, and con- struction work started on a hill in April 1259. The flattened top of the hill is about 400 metres in length and 150 metres wide. Water was raised to the top of the hill with special devices. A mosque and Helagu’s residence on the top of the hill was built by Muayya al-din al-Urdi. The building had a dome and its library contained some 400,000 volumes. There was a hole on the top of the dome through which sunrays entered. The image thus formed served for the measurement of the mean motion of the sun in degrees, and in minutes. Various times of the day were also determined in such a way. There were representations of celestial spheres, illustrations of the phases of the moon and signs of the zodiac. There were also terrestrial and celestial globes, maps of seven climes, and illustrations regarding the length of the days and nights. A terrestrial globe was made of pulp paper (or cardboard). A metallic celestial globe constructed in 1279 by Muhammad ibn al-Urdi (son of Muayyad al-din) is still preserved in Dresden Museum, Germany. The armillary sphere was fixed on the ground; traces of the places where instruments were placed can still be seen today. Al-Urdi has given a detailed account of the instruments, which included a mural quadrant, an armillary sphere with five rings and an alidade, a solsticial armilla, an equinoctial armilla, an azimuth ring with two quadrants equipped with alidades for the measurements of angles of elevation, a parallactic ruler, an instrument to determine azimuths, sine and versed sine instruments, and models of instruments prepared by al -Urdi. Nasir al-Din al-Tusi (d.1274) was director of this observatory. Helagu Khan never took a trip without consulting him. The main achievement of this observatory was the Ilkhani Zij completed in 1271, a copy of which exists in Bibliotheque Nationale in Paris (MS No. 779). There were 15 astronomers employed here including Ali ibn Umar al- Qazwini, al-Urdi, al-Akhlati, al- Maraghi, al-Maghribi and Qutub al- A Brief History of Observatories in the Islamic Worrld Review of Religions: September 200158 Din al-Shirazi. The revenues for the operation of this observatory were provided from Waqf ( I s l a m i c charitable endowments). It is said that twenty thousand dinars were spent on instruments. ‘The principal achievement of this observatory was the issue of a revised set of astronomical tables for computing the motions of the planets, together with a new a star c a t a l o g u e . ’ (S h o rt History of Science, W.T. Sedgewick, 1939, NY.) The observatory continued its operation under seven Ilkhani rulers. One of the rulers appointed Asil al- Din (d.1306) son of Nasir Al-Din as its director. It ceased operation under Uljaytu Khan in 1316. Tabriz Observatory The Ilkhanid ruler Ghazan Khan (1295-1304) built a mausoleum for himself along with other buildings consisting of a mosque, a monastery, two madrasas, a hospice for sayyids, an observatory, a hospital, a library, a house of law, a place of ablutions, a bath house, and a primary school. This complex was called Abwab al- Birr al-Sham as they were located in the suburb of Sham in Tabriz, Iran. The foundation was richly endowed and Waqf revenues were provided for its maintenance. A clock of great complexity was built for the observatory. Ghazan Khan had a very good knowledge of medicine besides a s t r o n o m y. He visited Maragha observatory many times. The con- struction was completed in 1304, and it remained operational for 15 years. The observatory provided salaries for a mudarris (professor) and a mueed (assistant), as well as for a treasurer. It is said that Ghazan Khan prepared a new calendar as he decided to unify different calendars. The Khani solar calendar was adopted in 1302. Samarqand Observatory Samarqand was an important cultural centre during the reign of Sultan IT IS SAID THAT THE FAMOUS SPANISH ASTRONOMER JABIR IBN AFLAH USED THE MINARET OF THE JAMI MOSQUE IN SEVILLE FOR MAKING OBSERVATIONS. THIS WAS IN FACT THE FIRST OBSERVATORY IN EUROPE. OVERLOOKING THE CITY OF SEVILLE, IT IS NOW CALLED LA GIRALDA TOWER, AND VISITED BY MILLIONS INCLUDING THIS AUTHOR IN 1999. Review of Religions: September 2001 A Brief History of Observatories in the Islamic Worrld 59 Timur (1369-1405) who built an observatory in this city in 1402. During the reign of Timur’s grandson Muhammad Tu rgay Ulugh Bey (1394-1449), the scientific activity in the city reached its zenith. Prince Ulugh Bey himself an accomplished scientist enjoyed to indulge in mathematical and astronomical matters. Al-Khashi, Qazizadeh al- Rumi and Ali Qushji (d.1474) were leading astronomers at this institution. Ulugh Bey took part in all the scientific meetings that took place in his palace before the construction of the observatory. The astronomical tables prepared by him in 1437 are called Zij al-Gurgani. A l – B i r j a n d i wrote Sharh Zij Ulugh Beyk, a commentary on the astronomical tables of Ulugh Bey. He also wrote a book on instrument making (Risala fee Alate Rasad ) a manuscript preserved in Raza Library, Rampur, India. Instruments for this observatory were made by Jalal al- Din al-Usturlabi. A copy of Ghiys al- Din Al-Kashi’s book Miftahul Hisab, in his own handwriting, is preserved at Nur Osmania Library, Turkey. Al- Kashi says in the introduction to his book that he wrote this for Bey’s library attached to the observatory. Ulugh Bey was himself director of this observatory; he made obser- vations of the fixed stars for eight years 1430-1437. It remained oper- ational for thirty years. T h e monumental size of the round building and its huge meridian arc made of masonry are a living tes- timony to its founder. The radius of the arc was equal to the height of the dome of the magnificent Ayasofya Mosque in Istanbul. There were beautiful models of ten celestial spheres, the seven known planets, and the fixed stars. There was a terrestrial globe divided into climes, mountains, seas and deserts. In 1908, the Russian scientist Vjatkin unearthed the underground remains of the meridian arc which was the major instrument of the observatory. The main observatory building was on the top of an 85-metre mountain, and the height of the building was about 30 metres. The building was demolished 50 years after Bey’s death, mainly to make use of the marble. It is stated in some sources that the obliquity of the ecliptic was measured here with the help of Sudsi Fakhri. In India, Raja Jai Singh prepared astronomical tables and in the introduction, he spoke of : ‘instruments such as those which were constructed in Samarqand’. They include an armillary sphere and a parallactic ruler. Al-Kashi has A Brief History of Observatories in the Islamic Worrld Review of Religions: September 200160 mentioned in his Zij Khaqani that a mural quadrant, a sun clock on the palace wall, water clocks and an astrolabe were also used here. Istanbul Observatory This observatory was founded on the suggestion of the Egyptian Taqi al- Din Ibn Maruf to Sultan Murad III (1574-1595). The construction work completed in 1577, the year the famous comet appeared on the skies. Taqi al-Din was the director of the observatory. The design of the main building was elaborate, with residence for the astronomers, administrative offices, and a library. There was a deep well or a tower for the daytime observation of the stars. Unfortunately the building was demolished in 1580 on advice received by Sultan Murad from religious leader Shayk al-Islam Qazidada. Taqi al-Din is reported to have measured the latitudes, and longitudes of all parts of the earth. Some of the instruments (compasses & rulers) used were portable. There were 15 astronomers on its scientific staff. The Astronomical tables of Ulugh Bey were revised here. Instrumentsused here are similar to those used by Tycho Brahe (1546- 1601) in his observatory in Denmark. Indian Observatories Following the Islamic tradition, Maharajah Sawai Jai Singh (1686- 1743) built several observatories in Indian cities including Dehli, Jaipur, Banares, Mathura and Ujjain, between 1728 and 1734. Instruments in these observatories were made of stone and lime, as brass instruments could not be large enough to indicate the minutes. Jai Singh made observations for seven years and made a star catalogue. He also prepared astronomical tables Zij Muhammad Shahi, for his patron Sultan Muhammad Shah. Summary In all the observatories mentioned here, many things were strikingly s i m i l a r. For instance astronomical tables were prepared, larger mosques were used for astronomical obser- vations, large instruments were used for which special buildings were constructed. These observatories were state institutions patronised by Kings, Sultans, and Ameers. There were huge libraries attached to the observatories with useful books on mathematics, algebra, medicine, geometry, and astronomy. People of various professions cooperated in their planning and construction. The administrative staff included treas- urers, librarians, and clerks. These observatories were places where scientific ideas were exchanged, discussions held and revised theories Review of Religions: September 2001 A Brief History of Observatories in the Islamic Worrld 61 created. Mathematical sciences and astronomy was taught to budding scientists. Astronomers of Islam sought to increase the sensitivity of the instruments and to render possible the detection and reading of increasingly smaller fractions of a degree by augmenting the size of the instruments. The meridian arcs of al- Khudanji and Ulugh Bey can be cited in this connection. The main work done in these observatories was of course to prepare astronomical tables based on fresh observations, but planetary motions and trajectories were also studied. Calendars were revised, and times figured out for religious festivals. At the Qasiyun observatory daily observations of the sun and moon were made for a whole year, while Jabir ibn Aflah also speaks of daily observations of the sun in Spain. Islamic Influence on Europe Modelled after the Islamic obser- vatories, many observatories sprang up in European cities like Paris (1666), Greenwich (1675), Leiden (1632), and Copenhagen (1637). Prior to these, Tyco Brahe had built two observatories on the Island of Hveen in Denmark. The Kassel observatory (1561) of Wilhelm IV of Hesse (1532- 1592) was the first European obser- vatory comparable to Islamic ones. Wilhelm IV observed a comet in 1558 using instruments originally developed in Islamic observatories. Greenwich observatory was equipped with a seven foot radius sextant and two pendulum clocks supplied by John Flamsteed. In addition there were two telescopes. The Paris observatory had a deep well that was used for daytime observations. There was also a quadrant of nine feet radius and a six feet sextant. A p r i v a t e observatory was built in Danzig (Poland) by Hevelius in 1639. Most of these observatories were connected to universities in those cities. Astronomical tables were made or old ones revised in these institutions; for instance Tycho Brahe’s tables were revised in Greenwich. Copernicus is reported to have used instruments similar to those designed for the Maragha Observatory. Al-Kashi has mentioned a ruler which was later used by Tycho Brahe, who used many Islamic instruments of great size like a mural quadrant, a wooden quadrant, brass azimuth quadrant, armillary sphere, and the parallactic ruler in his observatories in Uraniborg (1575), and Stjerneborg (1584). After 21 years, work could not continue as his patron Frederick II, King of Denmark died. Later on these observatories were moved to Prague and Benatky, A Brief History of Observatories in the Islamic Worrld Review of Religions: September 200162 where his patron was Rudolph II Emperor of Germany. It is a fact that Islamic scientific influences played a great part in the renaissance of the 12th century through translations of Arabic books and scientific treatises. In the fifteenth century it was Germany that came into close contact with the learning of Islam, specifically the Ottoman Empire. Elements of Euclid, written by al-Tusi was published in Arabic in Rome at the end of 16th century. In the middle of the 17th century, al-Tusi’s ideas on Euclidean postulates became available in Latin translations that influenced the work of Girolamo Saccheri in the 18th century. There is a striking resemblance in the trigonometries of al-Tusi and German astronomer (Johann Muller) Regiomontanus (1436-76). The lunar theory of Ibn al-Shatir was identical to that of Copernicus except for trivial differences in parameters. According to E.S. Kennedy: ‘the universes of these two individuals are geocentric and heliocentric respectively.’ It is said that Copernicus used a cinematic device thought out by al- Tusi. The instrument torquetum (the Turkish instrument) was also widely used in Europe. Muslim astronomers have left on the sky traces of their knowledge, which can be seen in the names of various stars including Acerb (scorpion), Algedi (kid), Altair (flyer), Deneb (tail), Pherkad (calf), Alcaid (blue- white star), Alcor (white star), Aldebaran (red star in constellation Taurus meaning follower from the Arabic a l – d a b a r a n), Algol (in Perseus), and Altair (bright star in constellation Aquila). Then there are technical terms that are Arabic in origin such as azimuth (Arabic al-Sumut – the ways), nadir and zenith (Arabic al-Samt), Alidade (Arabic al-idadah – moving radius), Almanac (Arabic al-Manakh). Two surface areas of the Moon in the Sea of Nectar are named after Albategnius (Al-Battani), and Abulfeda, while a surface area in the Sea of Clouds is called Arzachel (al-Zarqali). In conclusion we must state that Islamic civilization was indeed the birthplace of observatories. Early European observatories grew out of the observatories of medieval Islam, and their influence is etched in astronomy to this day. Review of Religions: September 2001 A Brief History of Observatories in the Islamic Worrld 63 References 1. The Observatory in Islam by Aydin Sayili, New York, 1981. First edition printed in Ankara, 1960. 2. I n t roduction to the History of Science by George Sarton, New York, 1925 3. S u rvey of Islamic A s t ro n o m i c a l Ta b l e s by E.S. Kennedy, Philadelphia, 1956. Further reading: • Al-Kashi – Miftah al-Hisab, Nur Osmania Library, Istanbul, MS No. 2967, Risala dar sharah Alati Rasad, Petrograd 1918, Zij Khaqani fee Takmil Zij al-Ilkhani, fee Nujum. Ay a s o f y a Library, Istanbul, MS No. 2692 • Jai Singh – Zij Muhammad Shahi , Sipahsalar Library, Tehran MS No. 671 • Al-Khazini – Zij al Muatabar al Sanjari, Murad Molla Library, Istanbul Ms No 859 • Al-Majriti, Maslama – Ghaya al- Hakim, ed. H Ritter, 1933 • Al-Urdi, Muayad al-Din – Kitab al Haya , Risala fee Kayfiyat al-Arsad • Al-Tusi – Zij Il-Khani, Zubda al-Haya, Ayasofya Lib. MS No. 2670, Kitab al Tahrir Usul le-Uqlidas, Rome MS 1594 • Nishaburi, Nizam – Sharh Tazkira fil Haya lee Tu s i. Sharh Zij ilKhani Ayasofya MS No. 2696 • Ibn Saeed al-Andulusi – Tabaqat al- Umam French trans. R. Blachere, Paris 1935 • Ibn Sena – Adabi Saltanat wa Wazarat, Persian • Al-Sufi, A.R. – Suwar al-Kawakib, Hyderabad 1954 • Taqi al-Din – Alati Rasadiya le Zij S h a h e n a s h i y a, Topkai Museum, Istanbul • Ulugh Bey – Zij, trans by Sedillot, Paris 1847 • Ibn Younus – Zij al Kabir al Hakimi, trans by Caussin 1803 • Ibn Zurayq – Talkhis Zij Ibn Shatir. • H. Suter – Die Mathematiker und Astronomen der Araber, 1902. Please put me on the mailing list for the Review of Religions for 1 year. I enclose subscription payment of £15.00 or $30.00 US. 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