Άbdul-Ra $$\d{h}$$ mān al-Şūfī and His Book of the Fixed Stars: A Journey of Re-discovery

Abstract

Al-Ṣūfī's Book of the Fixed Stars, dating from around AD 964, is one of the most important medieval Arabic treatises on astronomy. This major work contains an extensive star catalog, which lists star co-ordinates and magnitude estimates, as well as detailed star charts. Other topics include descriptions of nebulae, colors of stars and Arabic folk astronomy. Al-Ṣūfī's book was based on Ptolemy's classical work called the Almagest which was written around A.D. 137. Al-Ṣūfī updated Ptolemy's stellar longitudes from A.D. 137 to 964 by adding 12 degrees and 42 minutes on Ptolemy's longitude values to allow for precession. However, it is surprising that at present no English translation of al-Ṣūfī's treatise exists. Therefore this is a Doctorate thesis which includes for the first time a complete English translation of the main parts of al-Ṣūfī's work as well as a detailed study of this important book. The main topics which have been discussed in this study include a brief biography on al-Ṣūfī, the extant manuscripts of al-Ṣūfī's treatise, the structure of the book and star catalogue, and the star maps and charts. One of al-Ṣūfī's innovations in charting the stars was the production of dual illustrations for each of Ptolemy's constellations. One illustration was as portrayed on a celestial globe. The other illustration was as viewed directly in the night sky. Al-Ṣūfī's contribution to astronomy was not only limited to writing this book but he was also instrumental in developing the science of astronomy for a very long time. He also contributed to the building of an important observatory in the city of Shiraz as well as constructing many astronomical instruments such as astrolabes and celestial globes. His influence reverberated throughout history reaching as far as the end of the 19th century. This study also includes a major finding which is al-Ṣūfī's magnitude unique 3-step intermediate magnitude system. Al-Ṣūfī identified more than one hundred new stars which he mentioned in his commentaries on the constellation but they were not included in the tables nor were they mentioned in the Almagest or any other ancient star catalogs.