Friday, December 28, 2018

Abd al-Rahman al-Sufi: The star finder

Building upon and surpassing previous knowledge Islamic scientists blazed a trail for new discoveries in the 9th century. Mohammad Reza Jozi takes a look at the life of Abd al-Rahman al-Sufi

“What, have they not beheld heaven above them, how we have built it, and decked it out fair” (Qur’an, 50:6).
The above verse of the holy Qur’an, as well as several others, invites Muslims to look into the sky and ponder on its amazing creation. One of the Muslim scientists who responded to this invitation and contributed to the progress of the science of astronomy, was Abd al-Rahman ibn ‘Umar al-Sufi al-Razi, a Persian mathematician and astronomer who is known to westerners with various titles but most often with the Latinised name “Azophi” (al-Sufi). Sufi started his work when the Greek tradition of astronomy had died out centuries before but was revitalised during the second half of the eighth century by Muslim astronomers such as Abu Ma‘shar (Albumasar), al-Fazari, al-Nairizi, and al-Battani. Sufi was born on 8th November 904 in the city of Raay near modern Tehran. Of his early life and education not much is known but we know that in 948 when he was in his mid-forties he travelled to the city of Dinawar and Isfahan for further education. In 969 Ahud al-Dawla, king of the Buyid dynasty invited Sufi to Shiraz and appointed him as the chief astronomer of his court until his death in May 986. Sufi’s relationship with Ahud al-Dawla was so close that the latter regarded himself as a friend and pupil of Sufi. It was in this city that Sufi compiled his magnum opus Kitab Suwar al-Kawakib al-Thabita (Book on the Constellations of the Fixed Stars). Sufi wrote several books on the subject of astronomy all of which are in the Arabic language, such as on the use of the astrolabe, the celestial globe, and an introduction to the science of astrology. He also crafted a celestial globe of silver for Ahud-al-Dawla which was later exhibited in 1043/44 in the public library of Cairo by the Egyptian astrolabe maker Ibn al-Sinbadi. Sufi is however well known for his Kitab Suwar al-Kawakib which he authored when he was 61 years old and which he dedicated to his patron. In this book Sufi gives the detailed specifications of 48 constellations which Ptolemy introduced in his “Almagest”. These specifications are from the perspective of the observer, not from the perspective of the globe.
Sufi’s profound knowledge of astronomy becomes evident when he recalculates and corrects the positions and the magnitudes of many stars already listed in Almagest by Ptolemy
The main purpose of the Suwar al-Kawakib is to guide the observer who looks at the sky. Sufi’s profound knowledge of astronomy becomes evident when he recalculates and corrects the positions and the magnitudes of many stars already listed in Almagest by Ptolemy. Further to this, he describes each constellation with full details and then draws a table which consists of the location, longitude, latitude, colour and magnitude of each star inside the figure of that constellation. Sufi managed to observe 1027 stars in general and give the minutest details of each of them. This includes the name and the description of 40 stars from his personal observations which had not been discovered before nor were listed. Furthermore, he gives the first known record of the Large Magellanic Cloud (LMC) which some centuries later was observed by Amerigo Vespucci and Ferdinand Magellan and also three nebulous objects i.e. the Andromeda Galaxy, Brocchi’s Cluster and the Omicron Velorum Cluster. Also in this book Sufi complemented the 48 constellations introduced in Almagest with useful information about the derivation of the names of the stars in Arabic and their equivalents in Greek. One of the innovations of Sufi is his artistic illustration of the constellations which helps the reader to memorise and locate the position of the stars in the sky. This was an advantage which Almagest totally lacked. These illustrations represent the constellations twice; first in mirror image, as they appear on a celestial globe, and second as they actually appear in the sky. Today more than 90 manuscripts of Suwar al-Kawakib are preserved in the libraries and museums of the world. One of the most valuable manuscripts of this work which belonged to the celebrated Muslim astronomer Ulugh Beg (1394-1449) and was made around 1430 is now kept at Bibliotheque Nationale de France. However the oldest manuscript of Suwar al-Kawakib is now kept in Bodleian Library in Oxford – it was inscribed 26 years after his death by his son Abu’l-Hussein Sufi. Suwar al-Kawakib became a classic text in astronomy for many centuries both in Islamic lands and later in the Latin west. The first Persian translation of this book appeared in the hand of Nasir al-Din Tusi in the 13th century and its first Latin translation was produced by the order of the Alfonso X (1252- 1284), king of Castile. It was from this Latin translation that the western world became acquainted with the name of Sufi (Azophi) and Suwar al-Kawakib. In 1533 Petrus Apianus (1495-1552) from Ingolstadt published a star map in his Horoscopion generale (and also in his Instrument Buch of 1533) which contained several ‘Arabic’ asterisms (cluster of stars) apparently based on an Arabic copy of Sufi’s star atlas in his possession. In 1665 Thomas Hyde, the English orientalist and keeper of the Bodleian Library, in the commentary to his edition of Ulugh Beg’s Zij-i-Jadid Sultani introduced several quotations from Sufi’s book. This in turn became a source for Italian astronomer, Giuseppe Piazzi, who in 1814 extracted many names and fragments from Sufi and Ulugh Beg and incorporated them in his Praecipuarum Stellarum Inerrantum Positiones. (Image 3) As a tribute to this distinguished Muslim scientist the lunar crater “Azophi” and the minor planet 12621 “Alsufi” are named after him.
Muhammad Reza Jozi is graduated from Tehran University in Sociology. He is editor of An Anthology of Philosophy in Persia and consultant editor of the Great Islamic Encyclopedia

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