Ebu Ma’şer El Belhî

Astronomer and astrologist (B. 10 August 787?, Belh – D. 8 March 886, Vasıt / Baghdad). His full name is Ebu Ma’şer Ca’fer b. Muhammed b. Ömer el-Belhi. It is stated in sources that he was one of the Horasan Turcomans. He is known as Albumasal in the Western world of science. He spent his first years of his educations in his birthplace. He made his first scientific researches on Iranian history, native languages spoken in Horasan and Indian culture. Probably during the Caliphate of Memun (813-833) he went to Baghdad and was occupied with hadith science (words of Holy Prophet) until the age of forty-seven. After a while he became one of the major scholars of hadith science.

According to the sources about him, he was first interested in mathematics and later in astronomy and astrology which granted him reputation and he became famous in both of these sciences. It is also stated that he saw during a pilgrimage the library of Ali b. Yahya el-Müneccim in Kerker near to Baghdad which impressed him and attracted him to astronomy. After taking service with the Abbasid Caliph Mu’temid-Alellah’s brother and second crown prince Muvaffak he was accepted as the greatest scholar of astronomy and astrology of his age.

Ebu Ma’şer for the first time discovered tidal flow. He explained the essence of it and its relation with the moon. This knowledge later spread to European scientific environments. A researches of history of science, Philip K. Hitti, said; “It is Ebu Ma’şer who taught the principles and laws of tidal flow to Europe and who produced the first theories about it”.

He also gave opinions about the length of latitudes. The knowledge he provided about tidal flows and calculations of latitudes guided scientific environments. Ebu Ma’şer who is the author of numerous works on astronomy and calculation of times was in close relationship, other than Kindi, with famous scholar and astronomers of the period such as Sind b. Ali and Battani. It is known that in the field of history he was rather interested in scientific and cultural history than political history.

The works of Ebu Ma’şer, who said that stars not only determined time and caused the seasons but also affected psychological structures of people and their morality, belonged to primary sources of scientific environments during his age and following ages. Ebu Ma’şer who was assumed to have epilepsy passed away in Baghdad on the 8^th of March 886 around the age of 100.

WORKS:

el-Medhalü'l-kebi'r ila ilmi ahkami'n-nücum (It is on astronomy. A sample of it is present in Süleymaniye Library.), el-Medha1ü's- Sağir (On planets.), Kitabü'l-Kıranat (Translated into Latin and published several times in Europe.), Kitabü Tehavili sini'l- alem (Translated into Latin and published several times in Europe.), Kitabü Tehavili sini'l-mevalid (This work consists of nine articles.), Kitabü Asli'l-usul, Kitabü-Mevalidi's-sağir (On astrology.), Müzakeratü Ebi Maşer fi esrari ilmi'n-nücüm. (On astrology.), Kitabü's-Siham, Kitabü's İsbati ilmi'n - nücüm (Interpretation of Ali b. İsa el-Harrani's Risale ibtali sına"ati ahkami 'n - nücüm ), Kitabü'l-Üluf (On astrology.), Kitabü't- Taba'i i'l- kebir, Kitabü's -Sehmeyn ve amari'l-mülük ve'd-düvel, Kitabü'z Za'ircad ve'l - intiha'at ve'l - memerrat (On the history of astrology.), Kitabü'l İktira'nin- nahseyn fi burci's –Seratan (On astrology.) Kitabü's - Suver ve'l - hükmi aleyha (No information about it.), Zicü'l-hezarat, Kitabü'l Mizacat (On planets.), Kitabü'l-Enva' (On the calendar of stars.), Kitabü'l - Mesa'il, Kitabü'l-Emtar ve'r-riyah ve tagayyüri'l – ehviye (On astrology.), Kitabu Teba'i i'l-büldan ve tevellüdir-riyah (On astronomy and astrology.), Kitabü'l-Meyl fi tahvili sini'l-mevalid (No information about it.), Kitabü'l-İhtiyarat ala menazili'l-kamer (On the effects of stars on people).