Saturday, May 30, 2009


Abu'l-Abbas Ahmad ibn Muhammad ibn Kathir al-Farghani, born in Farghana, Transoxiana (present-day Fergana, Uzbekistan), also known as Alfraganus in the West and died in Egypt. He was Muslim astronomer and one of the famous astronomers in 9th century who involved in the measurement of the diameter of the Earth together with a team of scientists under the patronage of Al-Mamun and his successors in Baghdad, His most important work, written between 833 and 857, he wrote "Elements of Astronomy" ( Kitab fi al-Harakat al-Samawiya wa Jawami Ilm al-Nujum i.e. the book on celestial motion and thorough science of the stars), written about 833, a thorough, readable, nonmathematical summary of Ptolemaic astronomy. This was the book, which circulated in several Latin editions, was widely studied in Europe from the 12th to the 17th century and exerted great influence upon European astronomy before Regiomontanus. He accepted Ptolemy's theory and value of the precession, but thought that it affected not only the stars but also the planets. He determined the diameter of the earth to be 6,500 miles, and found the greatest distances and also the diameters of the planets.

Later he moved to Cairo, where he composed a treatise on the astrolabe around 856. Al-Farghani's activities extended to engineering. According to Ibn Tughri Bridge, he supervised the construction of the Great Nilometer at al-Fustat (old Cairo). It was completed in 861, the year in which the Caliph al-Mutawakkil, who ordered the construction, died. But engineering was not al-Farghani's forte, as transpires from the following story narrated by Ibn Abi Usaybi'a.

The Jawami, or 'The Elements' as we shall call it, was Al- Farghani's best-known and most influential work. Abd al-Aziz al-Qabisi (d. 967) wrote a commentary on it, which is preserved in the Istanbul manuscript, Aya Sofya 4832, fols. 97v-114v. Two Latin translations followed in the 12th century. Jacob Anatoli produced a Hebrew translation of the book that served as a basis for a third Latin version, appearing in 1590, whereas in the seventeenth century the Dutch orientalist Jacob Golius published a new Latin text version together with the Arabic original text in 1669, on the basis of a manuscript he had acquired in the Near East, with a new Latin translation and extensive notes. The influence of 'The Elements' on mediaeval Europe is clearly vindicated by the presence of innumerable Latin manuscripts in European libraries.

References to it by medieval writers are many, and there is no doubt that it was greatly responsible for spreading knowledge of Ptolemaic astronomy, at least until this role was taken over by Sacrobosco's Sphere. But even then, 'The Elements' of Al-Farghani continued to be used, and Sacrobosco's Sphere was evidently indebted to it. It was from 'The Elements' (in Gherard's translation) that Dante derived the astronomical knowledge displayed in the 'Vita nuova' and in the 'Convivio'.

The Fihrist of Ibn al-Nadim, written in 987, ascribes only two works to Al-Farghani: (1) "The Book of Chapters, a summary of the Almagest" (Kitab al-Fusul, Ikhtiyar al-Majisti) and (2) "Book on the Construction of Sun-dials" (Kitab 'Amal al-Ruk hamat).

The crater Alfraganus on the Moon is named after him.

No comments:

Post a Comment