Early Astronomy in the University of Michigan Collections

Islamic Astronomy: Introduction

Page of a rare book (fragment)

The study and practice of astronomy within Islamic scientific traditions has a rich and complex history traced in numerous theoretical treatises and commentaries, handbooks of tables and star catalogues, and descriptions of instruments, their use and manufacture.

Most of these texts were composed in Arabic, with others authored in Persian, Turkish or the other regional languages of the historically Islamicate world, and this significant corpus circulated in thousands of manuscript copies.

Islamic astronomical and cosmological traditions developed out of a range of ancient sources — to a certain degree pre-Islamic Arabian star lore, astronomical mapping, and prognostication, but also the vibrant scientific tradition of the Sasanian Persians which derived in large part from Greek and Indian astronomies, themselves incorporating earlier Egyptian and Babylonian astronomies.

A Sasanian royal astronomical canon is reported in early Islamic sources, revised during the reign of Khusraw Anūshirwān (r.531–579 CE) and known as Zīj al-Shāh. It was apparently this zīj (astronomical handbook) which was used by the astrologers commissioned by the Abbasid caliph al-Manṣūr (r.754–775) to determine the most auspicious day for the founding of his capital at Baghdad.

Indeed, a significant number of early Muslim astronomers were from Persianate areas and found patronage in the courts of the Abbasids and their functionaries.

Administrative functions and scholarly interest across court officials and nobles motivated the practice and development of astronomy, as well as the massive translation movement of the 8th and 9th centuries which brought texts from Sanskrit, Greek, Syriac and Persian into Arabic.

Greek astronomical texts became particularly influential, especially the works of Claudius Ptolemy (d. ca. 170) and early Muslim astronomers such as ʿAbd al-Raḥmān ibn ʿUmar al-Ṣūfī (d.986) are recognized for their engagement with Ptolemy’s works. However, they were not merely translators or conduits for Greek learning. al-Ṣūfī and the later Muslim astronomers he influenced — among them Naṣīr al-Dīn Ṭūsī (d.1274) and other astronomers of the Marāghah School, Ibn al-Shāṭir (d.1375/6)working in Damascus, and astronomers working in Samarqand under the amīr Ulugh Beg (d.1449) — tackled the problems of Ptolemaic theory and developed novel mathematical solutions. In turn, their improvements to Greek astronomy influenced European astronomers such as Copernicus (d.1543).

Especially well-known for establishing observatories — institutions where many astronomers and mathematicians collaborated to record and explain their observations — and for designing and manufacturing instruments, medieval Muslim astronomers elaborated cosmographical models, mathematical techniques and observed values which influenced the astronomies of several cultures, including those of Byzantium, Europe, South Asia and East Asia.

While the endeavors of astronomy very practically informed the performance of Islamic ritual — for example, determining the sacred direction of prayer, prayer times, or the beginning of the month of Ramadan — and procedures of wider social and administrative interest such as maintaining accurate calendars and even calculating horoscopes, Islamic scholars and practitioners of scholarly astronomy such as Muḥammad al-Khuḍarī al-Dimyāṭī (d.1870/1) engaged with the evolving mathematical, observational, and textual practices of astronomy as a science — valuable to be cultivated in its own right — and made numerous lasting contributions preserved in writings, instruments, and contemporary astronomical principles and techniques.

Stars and Constellations

Mathematical Models

Planetary Theory

Observatory at Samarqand

Study and Practice

Ancient Astronomy

Western Astronomy


ʿAbd al-Raḥmān ibn ʿUmar al-Ṣūfī (عبد الرحمن بن عمر الصوفي) (d.986): A 10th century Iranian astronomer who worked under the patronage of the Buyid ruler ʿAḍud al-Dawlah (r.949–983) and conducted astronomical observations at Shiraz, renowned for his knowledge of the fixed stars and constellations through his influential work Kitāb Ṣuwar al-kawākib al-thābitah (Book of the Images of the Fixed Stars).

ʻAlāʼ al-Dīn ʻAlī Qushjī (علاء الدين علي قشجي) (d.1474): Fifteenth century astronomer and mathematician who succeeded his teacher Qāḍīʼzādah al-Rūmī as director of the famous observatory constructed at Samarqand under Ulugh Beg’s direction and patronage and led the effort to produce and author the Zīj-i Sulṭānī.

Ibn al-Shāṭir, ʻAlāʾal-Dīn ʻAlī ibn Ibrāhīm (علاء الدين علي بن ابراهيم الأنصاري المعروف بابن الشاطر) (d.1375/6): Fourteenth century astronomer of Damascus who wrote extensively and elaborated an innovative astronomical system which successfully resolved some of the stubborn problems of Greek astronomy. His proposed solutions influenced Copernicus, who used his models and shifted them to a heliocentric arrangement.

Muḥammad al-Khuḍarī al-Dimyāṭī (محمد الخضري الدمياطي) (d.1870/1): Nineteenth century Egyptian astronomer and practitioner of scholarly astronomy who authored a commentary providing the practicing astronomer, astrologer or timekeeper (muwaqqit) a set of tables and instructions for setting a calendar and converting between calendars, measuring time and computing planetary and stellar positions, appearances and eclipses in Cairo.

Mūsá ibn Muḥammad Qāḍīʼzādah al-Rūmī (موسى بن محمد قاضي زاده الرومي) (d.1436?): Fifteenth century astronomer noted for his role in the work of the Samarqand observatory established in 1420 under Ulugh Beg and for writings which became widely used teaching texts in astronomy and mathematics.

Naṣīr al-Dīn Ṭūsī (نصیر الدین الطوسی) (d.1274): Towering intellectual figure of the thirteenth century known for his scholarship in the religious sciences, philosophy, mathematics, and particularly astronomy. He invented the Ṭūsī couple which provided the basic approach for solutions of the mathematical expression of some planetary motion. His theories emerged from his work overseeing the famous observatory at Marāghah (مراغه) in northeast Iran which he founded in 1259 with the patronage of Hülegü Khān (d.1265). The astronomical handbook or zīj (زيج) which he compiled — known as Zīj-i Īlkhānī — became a model for later efforts among Muslim astronomers.

Ulugh Beg (الأمير ألغ بيك) (d.1449): Fifteenth century governor of Transoxania and briefly Timurid sultan. He became famous for his patronage of mathematics and astronomy, establishing and supporting large madrasahs in Bukhara and Samarqand. He is perhaps most famous for the observatory established at Samarqand in 1420. He himself was knowledgeable and practiced in mathematics and astronomy, and gathered capable scholars who taught, designed instruments, and conducted the observational program culminating in an astronomical handbook (zīj) entitled the Zīj-i Sulṭānī or Zīj-i Gurkānī with a new star catalogue derived mainly from new, independent observations.


  • Khusraw Anūshirwān (Sasanian ruler, 531-579).

Sasanian royal astronomical canon known as Zīj al-Shāh is revised.

  • al-Manṣūr (Abbasid caliph, 754–775).

762 Baghdad is founded by the Abbasid caliph al-Manṣūr who commissioned astrologers who used Zīj al-Shāh to determine the most auspicious day for the founding.

  • ʿAḍud al-Dawlah (Buyid ruler, 949-983), patron of astronomer ʿAbd al-Raḥmān ibn ʿUmar al-Ṣūfī (d.986).

al-Ṣūfī’s Book of the Images of the Fixed Stars.

  • ʿAlāʾ ad-Dīn Muḥammad III Nizāri Ismāʿilī Imām and ruler out of Alamut (1221-1255).
  • Hülegü Khān (Il-Khān / Mongol ruler, 1256-1265).

ca. 1235 Naṣīr al-Dīn Ṭūsī (d.1274) composes his Risālah-i Muʻīnīyah for the son of his patron Muḥtasham Nāṣir al-Dīn (d.1257) in which he introduces the first version of his Ṭūsī couple.

1258 Mongol siege of Baghdad.

ca. 1259 Observatory at Marāghah is founded.

  • Sayf al-Dīn Tankiz (d.1340) rules in Damascus as Mamluk viceroy of Syria (1312-1340).

Ibn al-Shāṭir (ca.1306-175/6) composes a zīj for Sayf al-Dīn Tankiz.

  • Muḥammad Ṭaraghāy ibn Shāhrukh ibn Tīmūr, known as Ulugh Beg, appointed governor of Samarqand (1409).
  • Ulugh Beg appointed governor of Transoxania (1411).
  • Ulugh Beg reigns as Timurid sultan (1447-1449).

1417-1421 Madrasah constructed by Ulugh Beg at Samarqand, later headed by Mūsá ibn Muḥammad Qāḍīʼzādah al-Rūmī (d.1436?).

1420 Observatory at Samarqand is established under Ulugh Beg.

1437 Star catalogue of the Zīj-i Sulṭānī or Zīj-i Gurkānī originally completed.

  • Uzun Hasan (Aq Qoyunlu ruler, 1453-1478), patron of ʻAlī Qushjī.
  • Mehmet II (Ottoman sultan, 1444-1446, 1451-1481).

ʻAlī Qushjī (d.1474) departs Samarqand and is welcomed in Tabriz under the patronage of Uzun Hasan who sends him on an ambassadorial mission to Istanbul.

ʻAlī Qushjī is welcomed in Istanbul by Mehmet II and given an appointment teaching the natural sciences in the madrasah of the Aya Sofia.

  • French invasion and occupation of Egypt by the forces of Napoleon Bonaparte (1798-1801).
  • Muhammad ‘Ali Pasha (Ottoman governor of Egypt, 1805-1848).

1815/1816 Muḥammad al-Khuḍarī (1798/9-1870/1) travels to Cairo to train as a scholar in the traditional circles of learning at al-Azhar.

Select Bibliography

  • Adams, Danielle. Two Deserts, One Sky: Arab Star Calendars (available online).
  • Adams, Danielle. “Whose stars? Our heritage of Arabian astronomy.” The Planetary Society, 18 December 2018 (published online).
  • de Blois, François C., David A. King, and Julio Samsó. “Zīdj.” In Encyclopaedia of Islam, Second Edition, edited by Peri Bearman et al.
  • Feldhay, Rivka and Ragep, F. Jamil, eds. 2017. Before Copernicus: The Cultures and Contexts of Scientific Learning in the Fifteenth Century. Montreal: McGill-Queen’s University Press.
  • Islamic Scientific Manuscripts Initiative (ISMI) (available online).
  • Ragep, F. Jamil. “Astronomy.” Encyclopaedia of Islam THREE, edited by Kate Fleet, et al.
  • Saliba, George. 2007. Islamic Science and the Making of the European Renaissance. Cambridge, MA: MIT Press.
  • Sardar, Marika. “Astronomy and Astrology in the Medieval Islamic World.” In Heilbrunn Timeline of Art History. New York: The Metropolitan Museum of Art, 2000– (available online).
  • Sayılı, Aydın. 1960. The Observatory in Islam and Its Place in the General Development of the Observatory. Ankara: Türk Tarih Kurumu Basımevi.
  • Stolz, Daniel. 2018. The Lighthouse and the Observatory: Islam, Science and Empire in Late Ottoman Egypt. Cambridge: Cambridge University Press.