From: Thomas Hockey et al. (eds.). The Biographical Encyclopedia of Astronomers, Springer Reference. New York: Springer, 2007, pp. 970-971
Riḍwān al‐Falakī: Riḍwān Efendi ibn ʿAbdallāh al‐Razzāz al‐Falakī
Born Cairo, (Egypt)
Died Cairo, (Egypt), 7 August 1711
Riḍwān Efendi al‐Falakī was an Egyptian–Ottoman astronomer known for his production of astronomical tables as well as various instruments and globes. He was also noted for the many students that he trained. There is little information on his birth, youth, and education. However, we know that Riḍwān al‐Falakī studied in Cairo and received his astronomical education from distinguished scholars. Indeed, he never left Cairo except in 1680, when he visited Mecca for the ḥajj (pilgrimage). Besides writing on astronomy, Riḍwān al‐Falakī wrote a number of books on mathematics and geometry. According to the sources on Ottoman astronomy, his works were so abundant that the drafts of his books were considered a camel's load. At the request of the timekeeper Ḥasan Efendi, in 1700 and 1701 he prepared spheres and astronomical devices upon which he marked the Arabic names of stars that he located through observation. Among Riḍwān al‐Falakī's many students in astronomy, only Yūsuf al‐Jamāli (the servant of Ḥasan Efendi) is known.
The titles of 17 of Riḍwān al‐Falakī's astronomical works are known, most of which are extant. All were written in Arabic. Several works are adaptations of the work done at the Samarqand Observatory under Ulugh Beg. His Zīj al‐mufīd ʿalā uṣūl al‐raṣad al‐jadīd al‐Samarqāndī, or al‐Zīj al‐Riḍwānī, is an astronomical handbook with tables based on Zīj‐i Ulugh Beg but adapted for Cairo's latitude. It consists of four parts in addition to an introduction and various tables. Riḍwān al‐Falakī's al‐Durr al‐farīd ʿalā al‐raṣad al‐jadīd is possibly a commentary written on Ulugh Beg's Zīj; it contains an introduction, 12 sections, and a conclusion. Asnā al‐mawāhib fī taqwīm al‐kawākib is another work he adapted from Zīj‐i Ulugh Beg for Cairo's latitude.
Riḍwān al‐Falakī is also known for his works on timekeeping. Of these, probably the most extensive is Dustūr uṣūl ʿilm al‐mīqāt wa‐naṭījat al‐naẓr fī taḥrīr al‐awqāt. Other treatises treat eclipses, lunar‐crescent visibility, sundials, and Jupiter–Saturn conjunctions. For a listing of his works, see Ihsanoğlu et al. (1997), and Rosenfeld and Ihsanoğlu (2003).
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