The famous Iranian Islamic astronomer and mathematician, Sufi ar-Razi

Compiled By: Syed Ali Shahbaz

On December 7, 903 AD, the famous Iranian Islamic astronomer and mathematician, Abu'l-Hassan Abdur-Rahman ibn Amr as-Sufi ar-Razi was born in Rayy, (currently a southern suburb of Tehran).He was one of the greatest astronomers and astrologers and was patronized by Azud od-Dowla Daylami, the ruler of the Persian Shi'ite Muslim Buwayhid dynasty of Iran-Iraq-Oman to translate scientific texts from Greek, Pahlavi and other languages into Arabic. As-Sufi was known in medieval Europe as “Azophi”; and today modern scientists have named in his honour the moon crater “Azophi” and the minor planet “12621 Alsufi”.

He published his famous Book “Kitab al-Kawakeb as-Sabeta" (Book of Fixed Stars) in 964 AD, describing much of his work, both in textual descriptions and pictures. In the same year he made the earliest recorded observation (from Yemen) of what western scientists today call the "Andromeda Galaxy"; describing it as a "small cloud". These were the first galaxies other than the Milky Way to be observed from the Earth. He also identified over five centuries before Ferdinand Magellan what the West calls the "Large Magellanic Cloud", which was not seen by Europeans until the Portuguese Sailor’s voyage around the world in the 16th century. As-Sufi ar-Razi observed that the ecliptic plane is inclined with respect to the celestial equator and more accurately calculated the length of the tropical year.

He observed and described the stars, their positions, their magnitudes and their colour, setting out his results, constellation by constellation. For each constellation, he provided two drawings, one from the outside of a celestial globe, and the other from the inside (as seen from the earth), and this is another firm proof that in contrast to the Europeans, the Muslims knew the earth as a sphere. As-Sufi also wrote about the astrolabe, finding numerous additional uses for it. He described over 1000 different uses, in areas as diverse as astronomy, astrology, horoscopes, navigation, surveying, timekeeping, the direction of the Qibla (the holy Ka’ba in Mecca), and determination of the timing of the five-times daily prayers, etc. Since 2006, the Astronomy Society of Iran – Amateur Committee (ASIAC) – has been holding an international "Sufi Observing Competition" in his memory.

A related work by him is: “Kitab Suwar al-Kawakeb ath-Thamaniya al-Arba’een” (published for the first time in Haiderabad-Deccan at Da’erat al-Ma?aref al-Osmaniya in 1954).