The Ottoman contribution to science and technology during their six hundred year rule is beyond measure. This article is a brief outline of just some of the Ottoman scientific activities and related institutions that brought about the revival of culture, science, and learning in civilization throughout the Islamic world and beyond. To instantiate the Ottoman scientific contributions, the author focuses on two significant examples from astronomy and geography in the 16th century: the foundation of Istanbul Observatory and Taqi Al-Din's achievements therein, map making and mapmakers such as the famous sailors Piri Reis, Saydi Ali Reis and Macar Ali Reis.
Salim Aydüz, PhD*
Table of contents
In its history and development, the innovative features of Ottoman science are obvious and various. Whilst the older Islamic centres of science and culture influenced initially Ottoman scientific tradition, it quickly reached a point where it could itself influence these old centres and serve as an example to them.
Figure 1: The overview of the astronomical instruments and staff of the Istanbul Observatory with Taqi Al-Din Rasid at work. Source: Shahinshahnāme Istanbul University Library, F 1404, fol. 57a.
The great changes in the scientific and educational life of the Ottomans were achieved over an extensive period of time. Consequently, it is difficult to connect the radical changes in Ottoman history to specific events or to start from a certain date. In general, "old and new" existed side by side. To substantiate such a claim, focus will be laid in this section on the formation and development of the classical Ottoman scientific tradition that was based on the Islamic classical scientific tradition, including the heritage of the Seljuks and other Muslim and Turkish states .
The Ottoman Empire was established as a small principality at the turn of the 14th century and gradually expanded into the Byzantine Empire and other Muslim and non-Muslim states. Its authority reached its highest point in the 16th century, and it became the most powerful state of the world. The Empire extended from Central Europe to the Indian Ocean and lasted for many centuries by keeping the balance of power with modern Europe .
Scientific activities in the Ottoman state emerged and developed in Anatolian cities from the scientific legacy and institutions of the pre-Ottoman Seljuk period and benefited from the activities of scholars who came from Egypt, Syria, Iran, and Turkestan—that is, from the substantial scientific and cultural centres of the time. Alongside the old centres of Islamic civilization, new centres, such as Bursa, Edirne, Istanbul, Amasya, Skopje, and Sarajevo flourished during to Ottoman period. The developments of this period form the heritage that constitutes the cultural identity and scientific legacy of present-day Turkey, as well as an important part of the intellectual history of several Middle Eastern, North African, and Balkan countries. The Ottomans also benefited greatly from their non-Muslim subjects and European neighbours, and provided very favourable working conditions for scientists from many different fields, including medicine, astronomy, and mathematics, by inviting them to conduct their studies at the important centres of science and culture in the Islamic world . Engaging the services of scientists and artists from either the west or the east as needed, without regard to religion or nationality, was an established and advantageous practice in the Ottoman Empire .
Figure 2: The figure of the Sextant (mushabbaha bi'l-monātiq), an important astronomical instrument of Tāqī al-Din. Source: Ālāt al-rasadiya li-zīj al-shāhinshāhiyya, Library of the Topkapi Palace Museum, Hazine 452, fol. 14b.
During the classical period, Ottoman scientists and scholars showed remarkable success in developing science and were able to produce many works in various branches. This paper provides an overview, with examples, of the formation and development of Ottoman science and scientific activities in the fields of geography and astronomy.
From as far back as the time of the Prophet, we know that Muslims had needed astronomy for the determination of times, an important factor in religious duties, and geography to find the direction of the Ka'ba. The precise calculation of the prayer times, as well as of the beginning and the end of the daily fast in the month of Ramadan, fell naturally within the domain of the astronomer. It is true that for the times of regular prayers, for example, Muslims were given approximate directions and were allowed some latitude; simple rules concerning these matters could be found in the Traditions. From the very beginning of Islam, Muslim scholars had to work on these two subjects under very strict rules. Due to closeness of the fields, most of the Muslim scholars had a deep knowledge of both sciences and they produced a considerable number of books.
Astronomical studies in the Islamic civilization started in the very early days. Observations of the sun and the moon and the calculation of the prayer times required precision. The observatory was one of the most highly developed institutions of science and learning in Islam and one of the high-water marks of the Muslim civilization. There is no doubt that the observatory, as a specialized scientific institution, owes a great deal to Islam. It may very reasonably be claimed that it was in Islam that the observatory, as a specialized institution with an official and legal status and with a fixed location where observation and other work on stellar bodies was systematically carried out through the cooperation of several scientists, first came into existence.
Already early in the 9th century, the Caliph Al-Ma'mun initiated the tradition of founding observatories in Islam, by founding two major but very short-lived observatories, the Shammasiya in Baghdad and Qasiyun in Damascus. There are eight other examples of the building of full-fledged and elaborate official state observatories in the Islamic realm up to the 17th century.
The Maragha Observatory, founded in 1259 under the patronage of Hulagu, was one of the most elaborate institutions of its kind and the scene of important work. Prince Ulugh Bey built another gigantic observatory in Samarqand in 1420, and finally the Tophane Observatory in Istanbul was founded by Murad III in 1577.
2.1. Istanbul Observatory
In the Ottoman civilization, scientific institutions, in the field of astronomy, included the chief astronomer's office (munajjimbashi), the muvaqqithānes and the Istanbul Observatory. Though one can find original and translated works in the fields of astronomy and astrology from the early period, the first calendrical works only began during the time of Sultan Murad II (1421-1451). These calendars were prepared as palace almanacs and we have no idea about the authors . They continued the classical Islamic astronomical tradition in this field, and combined the traditions of both the Samarkand and Maragha astronomy schools of astronomy in their works. Ulug Bey's Zīj, which was prepared in the Samarkand observatory, became a very significant manual for Ottoman astronomers and astrologers .
The Ottomans had well organized astronomical institutions such as the post of Chief-astronomer (munajjimbashilik) and time keeping houses (muwaqqithānas). In the Ottoman palace administration, the person in charge of directing the astronomers was called munajjimbashi, that is Chief Astronomer. The position of Chief Astronomer was established sometime between the late 15th and early 16th centuries. The Chief Astronomer's most important duty was the preparation of annual calendars. They were responsible for determining the beginning of fasting times (imsāqiya) before the month of Ramadan and preparing horoscopes (zāyija) and astronomical tables (zījs) for the palace people and prominent officials.
The timekeeper's offices (muvaqqithānes) were public buildings located in the courtyards of mosques or masjids in almost every town. They were widely built by the Ottomans especially after the conquest of Istanbul. They were administered by the foundation (waqf) of the complex (külliye) and the people who worked in the muvaqqithānes were named muvaqqit, meaning the person who kept the time, especially for the times of prayer.
In addition to other science related institutions, the observatory founded in Istanbul was administered by the chief astronomer Taqī al-Dīn al-Rasid (d. 1585). The first Ottoman observatory was also the last big observatory of the Islamic Civilization. With the support of Sultan Murad III, he started the construction of the Istanbul observatory. As well as using the existing instruments of observation, Taqī al-Dīn invented new ones in order to determine the equinoxes. He also developed and used gravity and spring driven mechanical clocks and invented a six-cylinder pump (engine) for raising water in a continuous manner . In addition, he wrote more than thirty books in mathematics, astronomy, mechanics, and medicine.
Taqi al-Din, who was born in Damascus in 1526, worked for a time as a qadīi and a teacher after completing his education in Damascus and Egypt. During his time in Egypt and Damascus, he produced some important works in the fields of astronomy and mathematics. In 1570, he came to Istanbul from Cairo, and one year later (1571-2) was appointed Chief Astronomer (Munajjimbashi) on the death of the Chief Astronomer Mustafa b. Ali al-Muwaqqit. Taqi al-Din maintained close relationships with many important members of the ulemā (scholars) and statesmen, chief among whom was Hoca Sādeddin, and was presented to Sultan Murad by the Grand Vizier Sokullu Mehmed Pasha .
Taqi al-Din informed Sultan Murad, who had an interest in astronomy and astrology, that the Ulug Beg's Astronomical Tables contained certain observational errors, resulting in errors in the calculations based on those tables. Taqi al-Din indicated that these errors could be corrected if new observations were made and proposed that an observatory be built in Istanbul for that purpose. Sultan Murad was very pleased to be the patron of the first observatory in Istanbul and asked that construction begin immediately. He also provided all the financial assistance required for the project. In the meantime, Taqi al-Din pursued his studies at the Galata Tower, and continued them in 1577, at the partially completed new observatory called Dār al-Rasad al-Jadīd (the New Observatory).
The observatory, consisting of two separate buildings, one large and one small, was constructed at a location in the higher part of Tophane in Istanbul. Taqi al-Din had the instruments used in the old Islamic observatories reproduced with great care. In addition, he invented some new instruments, which were used for observational purposes for the first time. The observatory had a staff of sixteen people: eight "observers" (rāsid), four clerks, and four assistants .
The observatory was designed to provide for the needs of the astronomers and included a library largely consisting of books on astronomy and mathematics. This institution was conceived as one of the largest observatories in the Islamic world and was completed in 1579. It was comparable to Tycho Brahe's (1546-1601) Uranienborg observatory built in 1576 . In addition, there is a striking similarity between the instruments of Tycho Brahe and those of Taqi al-Din but those of Taqi al-Din were of superior quality . When compared with those of his contemporary Danish astronomer, Taqi al-Din's observations are more precise.
In Taqi al-Din's astronomical tables, called the Sidratu Muntaha'l-Afkār fī Malakut al-Falak al-Davvār (Lotus of Culmination of Thoughts in the Kingdom of Rotating Spheres), Taqi al-Din states that he started astronomical activities in Istanbul with 15 assistants in 1573 . The observatory continued to function until 22 January 1580, the date of its destruction. Religious arguments were put forth to justify this action, but it was really rooted in certain internal political struggles .
2.2. New observational instruments of Taqi al-Din
Taqi al-Din invented new observational instruments that were added to those already in use for observation in the Islamic world. Among the instruments invented by Taqi al-Din in the observatory were the following:
- The Sextant (mushabbaha bi-'l manātiq): used to measure the distances between the stars. Taqi al-Din's mushabbaha bi'l manātiq and Tycho Brahe's sextant should be considered among the great achievements of the 16th century astronomy. A mushabbaha bi-l manātiq is composed of three rulers. Two of them are attached as the rulers of the triquetrum. An arc is attached to the end of one of the rulers. Taqi al-Din made this instrument to observe the radius of Venus that was mentioned in the Xth book of the Almagest .
- The instrument with cords (Dhāt al-awtar): designates the spring and autumn equinoxes. Some astronomers set up a ring, which was not divided, parallel to the equator to designate this. The instrument was composed of a base in the form of a rectangle and four columns. The two columns were set on this base so that a string was stretched between them. One of them was equal to the cosine of the latitude of the country and the other to the sine. A hole was made on each of these parts according to this proportion. A rope was hung from these holes with a plumb .
Figure 3: The figure of Dhāt al-awtār. Source: Ālāt al-rasadiya li-zīj al-shāhinshāhiyya, Library of the Topkapi Palace Museum, Hazine 452, fol. 13b.
- The astronomical clock: Taqi al-Din used a mechanical clock, which he made himself for his observations, and a wooden wall dial, which he set up in the observatory. He wrote in The Astronomical Instruments for the Emperor's Table: "The ninth instrument is an astronomical clock. The following statement is recorded from Ptolemy: ‘I would have been able to establish a great regularity in method if I was able to measure the time precisely.' Now Taqi al-Din planned, with the help of God, the astronomical clock by the command of the Sultan, God perpetuates his ruling days. Thus, he was able to do what Ptolemy had failed to do." Taqi al-Din says in Sidrat al-muntahā: "we built a mechanical clock with a dial showing the hours, minutes and seconds and we divided every minute into five seconds." This is a more precise clock than clocks used previously and is, as a result, considered to be one of the most important 16th century developments in applied astronomy .
When we compare the instruments which Taqi al-Din used in his observatory with those used by Tycho Brahe, they are mostly similar, but some of Taqi al-Din's are larger and more precise. Both, for example, used a mural quadrant (Libna) for the observations of the declinations of the sun and the stars. It is said that Taqi al-Din preferred the mural quadrant to the Fakhri sextant (Suds-i Fakhrī) and two rings used by previous astronomers. Taqi al-Din's quadrant was composed of two brass quadrants with a radius of six meters; it was placed on a wall and erected on the meridian. Tycho Brahe's similar instrument was only two meters in diameter .
In his work, Taqi al-Din integrated two traditions of astronomy, those of Damascus and Samarkand. His first task at the observatory was to correct the Zīj book (Astronomical Table) of Ulugh Beg. He also undertook various observations of eclipses of the sun and the moon. The comet that was present in the skies of Istanbul for one month during September 1578 was observed day and night and the results of the observations were presented to the sultan. As a result of the new methods he developed and the equipment he invented, Taqi al-Din was able to approach his observations in an innovative way and produce novel solutions to astronomical problems. He also substituted the use of a decimally based system for a sexagesimal one and prepared trigonometric tables based on decimal fractions. He determined the ecliptic degree as 23° 28' 40", which is very close to the current value of 23° 27'. He used a new method in calculating solar parameters. He determined that the magnitude of the annual movement of the sun's apogee was 63 seconds. Considering that the value known today is 61 seconds, the method he used appears to have been more precise than that of Copernicus (24 seconds) and Tycho Brahe (45 seconds). Taqi al-Din also wrote the first Ottoman book on automatic machines, titled el-Turuq al-Saniyya fi'l-ālāt al-rūhāniyya .
The observatory was witness to a great deal of activity within a short period of time. Observations undertaken there were collected in the above mentioned treatise Sidratu Muntahā'l-Afkār fī Malakūt al-Falak al-Davvār.
2.3. Mustafa bin Ali Al-Muwaqqit
Mustafa b. Ali al-Muwaqqit al-Salīmī was another essential Ottoman polymath scholar . He was well-known in the second half of the 16th century as an astronomer, mathematician, geographer, clock-maker (sa'atji) and muwaqqit (timekeeper). He made valuable contributions in the fields of astronomy and geography, producing many books of which those on making and using astronomical instruments are particularly important. These books were used as textbooks in madrasas, and some of them were copied until the middle of the 19th century.
Figure 4: The figure of astronomical clock. Source: Ālāt al-rasadiya li-zīj al-shāhinshāhiyya (T), Library of the Topkapi Palace Museum, Hazine 452, fol. 16a.
He was initially timekeeper at the Yavuz Selim Mosque in Istanbul and later became the Chief Astronomer (munajjimbashi) for ten years. He took astronomy courses and became muwaqqit at the Sultan Selim Mosque Muwaqqithana. He wrote most of his works while holding this post. He invented a new instrument for astronomical observation called the "rub-i āfākī" (horizontal quadrant).
There are 24 works which are definitely known to have been written by him; three in Arabic, the rest is in Turkish. By writing in the Turkish language about astronomical matters, he was aiming to make astronomical works accessible in this language who was becoming the scientific language of the Ottoman Empire. He also produced new and original solutions to astronomical problems. Therefore, his ideas became widely diffused among astronomers, muwaqqits and other educated people. In particular, his book explaining astronomical instruments was very popular among those interested in astronomy. In addition to astronomy, he also wrote three treatises of geography: Hallu Dā'irati Mu'addil al-Nahār, I'lam al-‘Ibād fī A'lām al-Bilād I'lām al-‘Ibād fī A'lām al-Bilād and Kifayāt al-Wakt li Ma'rifat al-Dā'ir wa Fazlihī wa al-Samt .
Figure 5: Sample extracts form Mustafa b. Ali al-Muwaqqit's I‘lam al-‘Ibād fī A‘lām al-Bilād. Source: Kandilli Rasathanesi El Yazmalari 1: Türkçe Yazmalar, proje sorumlusu: Günay Kut, İstanbul: Boǧaziçi Üniversitesi Yayinevi, 2007, p. 538.
As in the field of astronomy, the Ottomans continued the classical tradition in the field of geography. The Ottomans needed geographical knowledge in order to determine the borders of their continuously expanding territory and to establish control over military and commercial activities. They made use of both the geographical works of