Al-Farghani
Encyclopedia
also known as Alfraganus in the West was a Persian astronomer and one of the famous astronomers in 9th century. The crater Alfraganus on the Moon is named after him.
of the diameter
of the Earth
by the measurement
of the meridian arc
length together with a team of scientists under the patronage of al-Ma'mūn
in Baghdad
. Later he moved to Cairo, where he composed a treatise on the astrolabe around 856. There he also supervised the construction of the large Nilometer
on the island of al-Rawda (in Old Cairo) in the year 861.
. It was translated into Latin in the 12th century and remained very popular in Europe until the time of Regiomontanus
. Dante Alighieri
's knowledge of Ptolemaic astronomy, which is evident in his Divina Commedia as well as other works such as the Convivio
, seems to have been drawn from his reading of Alfraganus. In the 17th century the Dutch orientalist Jacob Golius published the Arabic text on the basis of a manuscript he had acquired in the Near East, with a new Latin translation and extensive notes.
Life
He was involved in the calculationCalculation
A calculation is a deliberate process for transforming one or more inputs into one or more results, with variable change.The term is used in a variety of senses, from the very definite arithmetical calculation of using an algorithm to the vague heuristics of calculating a strategy in a competition...
of the diameter
Diameter
In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints are on the circle. The diameters are the longest chords of the circle...
of the Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
by the measurement
Measurement
Measurement is the process or the result of determining the ratio of a physical quantity, such as a length, time, temperature etc., to a unit of measurement, such as the metre, second or degree Celsius...
of the meridian arc
Meridian arc
In geodesy, a meridian arc measurement is a highly accurate determination of the distance between two points with the same longitude. Two or more such determinations at different locations then specify the shape of the reference ellipsoid which best approximates the shape of the geoid. This...
length together with a team of scientists under the patronage of al-Ma'mūn
Al-Ma'mun
Abū Jaʿfar Abdullāh al-Māʾmūn ibn Harūn was an Abbasid caliph who reigned from 813 until his death in 833...
in Baghdad
Baghdad
Baghdad is the capital of Iraq, as well as the coterminous Baghdad Governorate. The population of Baghdad in 2011 is approximately 7,216,040...
. Later he moved to Cairo, where he composed a treatise on the astrolabe around 856. There he also supervised the construction of the large Nilometer
Nilometer
A Nilometer was a means of measuring the River Nile's clarity and for measuring the water level of the Nile river during the annual flood season....
on the island of al-Rawda (in Old Cairo) in the year 861.
Works
His textbook Elements of astronomy on the celestial motions, written about 833, was a competent descriptive summary of Ptolemy's AlmagestAlmagest
The Almagest is a 2nd-century mathematical and astronomical treatise on the apparent motions of the stars and planetary paths. Written in Greek by Claudius Ptolemy, a Roman era scholar of Egypt,...
. It was translated into Latin in the 12th century and remained very popular in Europe until the time of Regiomontanus
Regiomontanus
Johannes Müller von Königsberg , today best known by his Latin toponym Regiomontanus, was a German mathematician, astronomer, astrologer, translator and instrument maker....
. Dante Alighieri
Dante Alighieri
Durante degli Alighieri, mononymously referred to as Dante , was an Italian poet, prose writer, literary theorist, moral philosopher, and political thinker. He is best known for the monumental epic poem La commedia, later named La divina commedia ...
's knowledge of Ptolemaic astronomy, which is evident in his Divina Commedia as well as other works such as the Convivio
Convivio
Convivio is a work written by Dante Alighieri roughly between 1304 and 1307. It contains details of the author's growing interest in philosophy, particularly in reference to the works of Cicero and Boethius...
, seems to have been drawn from his reading of Alfraganus. In the 17th century the Dutch orientalist Jacob Golius published the Arabic text on the basis of a manuscript he had acquired in the Near East, with a new Latin translation and extensive notes.
Further reading
- Jacobus Golius (ed.), كتاب محمد بن كثير الفرغاني في الحركات السماوية وجوامع علم النجوم، بتفسير الشيخ الفاضل يعقوب غوليوس / Muhammedis Fil. Ketiri Ferganensis, qui vulgo Alfraganus dicitur, Elementa astronomica, Arabicè & Latinè. Cum notis ad res exoticas sive Orientales, quae in iis occurrunt, Amsterdam 1669; Reprint Frankfurt 1986 and 1997.
- El-Fergânî, The Elements of Astronomy, textual analysis, translation into Turkish, critical edition & facsimile by Yavuz Unat, edited by Şinasi Tekin & Gönül Alpay Tekin, Harvard University 1998.
- Richard Lorch (ed.), Al-Farghānī on the Astrolabe. Arabic text edited with translation and commentary, Stuttgart, 2005, ISBN 3-515-08713-3.