Fergânî

Mathematician and astronomer (B. ?, Fergana - D. 861). His full name was Ebû’l Abbâs Ahmed b. Muhammed b. Kesîr el-Fergânî’dir. He was one of the outstanding mathematicians and astronomers of the Abbasids period. Although we don’t have sufficient information about the life of Fergânî, he is supposed to have been born in Fergana. Famous mathematics and astronomy scientist Ahmed Fergânî, who was supposed to have been born in early 9^th century, was from the Fergana region of Turkistan, a place among the science and culture centres of its period. Although there is no information about his birth date in the collections of biographies, which are the first hand resources of our history of science and culture, it is recorded that his father’s (who is also an astronomer) name was Muhammed and his grandfather’s name was Kesir.

Ahmed Ferganî obtained his initial knowledge in Fergana, the place where famous scientists had grown and he obtained his knowledge on astronomy from his father. Once he reached a certain level, in order to add new knowledge to the existing one, he went to Baghdad, the science, culture and also the caliphate centre of its period. Ferganî lived nearly half of his life there and made his knowledge on mathematics and astronomy accepted among the Baghdad science environment within a short period. He took place among the most famous scholars of the periods of Me’mun and el-Mütevekkil, who were the Abbasid caliphs praised within the science history due to their contribution to the development of science.

Fergânî studied in the fields of astronomy, mathematics, geography and mechanics. Among them, he focused more on astronomy. In his scientific studies, he made empirical examinations and researches; he studied on the movements of the celestial bodies. He was among the first criticizers of the Ptolemaiosian astronomy, which did not comply with the principles of Koran and not rational. He proved that the celestial bodies were not irrational spiritual objects but rather rational, solid, homo-synthetic objects with circular motions. He investigated the volumes and sizes of the universe and the planets and their distances. His calculations were accepted as invariant measures in the astronomy of the West until Copernicus and used for centuries.

On the other hand, according to İbn Ebû Usaybia, Fergânî was not successful enough compared to his knowledge and he couldn’t conclude anything he started. But at this point, it can be said that Fergânî was not originally an engineer and that’s why he was unsuccessful in putting his theoretical knowledge into practice.

The work which caused Fergânî, the big astronomy and mathematics scientist grown in the 9th century and determined the ecliptic slope for the first time, to gain fame in  the Western world more than in the Islamic world is “Cevâmi’u ilmi’n – nücûm” and “Usûlü’l-harekâti’s-semâviyye”. The manuscript copies of this work are found in the library of Princeton University in Oxford, Paris, Cairo and America. Although it is a summary of the Ptolemaeus’s work “el-Mecisti”, it has a separate importance in terms of either the information on calendars and dates it gives within the first and second sections or the objections he asserted against Ptolemaeus. Even though the books of many Islam astronomers have been translated into Latin previously, none of them had an impact on the Western astronomers as big as the impact of “Cevâmi”. The main reason is doubtlessly that, the systematic and discourse of this work is as perfect as its content. “Cevâmi”, which consists of thirty sections, was named as “Kitâbü’l-Fusûl ihttiyârü’l- Me-cistî” by İbnü’n-Nedim. On the other hand, as mentioned above, İbnü’l-Kıftî thought that Ahmed b. Muhammed b. Kesir and Muhammed b. Kesir were two different persons and attributed the work to Ahmed Fergânî with the name “el-Med-hal ilâ ilmi hey eti’l-eflak ve hare-kâti’n-nücûm” and to Muhammet Fergânî with the names “Kitâbü’l-Fuşûl” and “Kitâbü İhtişâri’l-Mecistî” as two different works. It shows that “Cevâmi” has got many different names within the literature. Hence, on the outer cover of the Arabic text published by Jacobus Golius in 1669 in Amsterdam with a new Latin translation, hence “Kitâb fi’l-hare-kâti’s-semâviyye ve cevâmi’u ‘ilm’n-nücûm” and it was written as “Kitâb fi uşûli ‘ilmi’n-nücûm” on the inner page. The work is shortly known as “Ele-menta astronomica” in the Western world.

In various sections of “Cevâmi”, different topics such as the Arabic, Syrian, Roman, Iranian and Egyptian calendars; world’s position in the space and its movements, ecliptic slope; famous countries and cities; earth measurements; the positions and movements of the sun, moon, stars and the planets; states of the stars and the moon; phases of the moon; solar and lunar eclipse were addressed. “Cevâmi”, documents in detail the Ptolemaeus’s astronomy, what was completely descriptive and out of mathematics, and possesses a good systematic. However there were some numerical value mismatches in the first editions of its translations in the West.  

Another work of Fergânî is “el-Kâmil fi şan’a-ti’l-usturlâb”. It is about the geometry, star calculations, astrolabe and mathematical theories. There are different manuscript copies of this work...

Although the date of death of Fergânî is not known exactly, he is estimated to have died in 861 or a few years later.

MAIN WORKS: 

Usul el-İlm el-Nücum (It is a work on the stars. Other names used are: El-Medhal fi el-Mejisti, El-Medhal ila İlm el-Heyet el-Eflak, Kitab el-Füsul el-Selasin), İlelü Zici’l-Hârizmî (In this book not existing now, it is known that Fergânî had explained Hârizmî’s calculations. It is said that Bîrûnî had benefited from this work.), Cedvelü’l-Ferğan’î, “Amelü’l-ruhâmât, İlmü’l-heye, El-Kamil fi el-Usturlab (About astrolabe manufacture. Also known as Fi Sanat el-Usturlab).

REFERENCE: Mehmet Tahir Bursalı / Türklerden Yetişen Nücûm Heyet ve Riyaziye Ulemâsı (1897, s. 42), Prof. Dr. W. Barthold / İslâm Medeniyeti Tarihi (çev. M. Fuat Köprülü, 1940), Türkiye Diyanet Vakfı İslâm Ansiklopedisi (c.12, 1995), Henry Corbin / The Voyage and the Messenger: Iran and Philosophy, (North Atlantic Books 1998), Sir Patrick Moore / The Data Book of Astronomy (2000), İhsan Işık / Ünlü Bilim Adamları (Türkiye Ünlüleri Ansiklopedisi, C. 2, 2013) - Encyclopedia of Turkey’s Famous People (2013).