Early Astronomy in the University of Michigan Collections

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