Habeş El Hasib El Mervezî

Astronomi Bilgini, Matematik Bilgini, Bilgin

Diğer İsimler
Habeş el-hâsib Ahmed b. Abdillâh el-Mervezî, Bağ­dadî, Hâsib

Habeş el-HÂSİB Astronomer and mathematician (B. 770, Merv / Turkmenistan - D. 864, Baghdad). His full name was Habeş el-hâsib Ahmed b. Abdillâh el-Mervezî’dir. We have insufficient information about his life. He spent most of his life in Baghdad, and he lived through the periods of Abbâsî khalifs Me’mûn and Mutasım-Billâh. He was also known as Bağdadi because he stayed here for a long time. It is not certain if Habeş was his name or nickname. It is thought that he was known / called this way probably because he was very dark-colored. The nickname Hâsib was related to his being a mathematician. It is known that he did astronomy observations in Baghdad between 829 and 864. It is estimated that he lived for more than a hundred years and probably died somewhere between 864 and 874. İbnü'l-Kıftî said that his son Ebû Ca­fer was also famous for his knowledge of astronomy and making astronomy tools.

Resources mention that Habeş, one of the first Muslim astronomers and mathematicians, followed the Indian mathematics and astronomy model in the beginning of his scientific life and based his first “zîcde” (map of stars) on the Sindhind (Siddhanta) tradition. Although it is not certain whether it was actually in the astronomy observers group protected by the Khalif Me’mûn, it is understood from his “ez-Zîcü’l-Mümtehan” that he followed their works closely and tested their conclusions together with his own observations. In this work and his later works, Habeş proved that he knew about Greek astronomy, as well as Indian astronomy. Although he went beyond that, he arranged his maps according to the Ptolemy model. It is understood that his research had a strong influence on his later colleagues.

Ahmed b. Abdullah el-Mervezî el-Bağdadî was one of the important figures of the early Islam astronomy and trigonometry. The first to mention his name, İbn Nedîm (D. 990), talked about him in “el-Fihrist” as one of the first observers. Another resource mentioning Habeş, İbn el-Kıftî (D. 1248/1249), said in his “İhbâr el-Ulemâ bi-Ahbâr el-Hukemâ” that Habeş’ nickname was Habeş el-Hâsib. As İbn Nedîm did, he reported that he had been from Merv (in Turkmenistan), but he lived in Baghdad.

Ebü’l-Hasan İbn Yûnus, through whom we know that Habeş performed observations in Baghdad for thirty five years, criticized his determination of latitudes of Venus and Mercury, but later he was praised by many authors. For example Ebû Nasr İbn Irak, wrote a booklet about this “zîc”, which was titled as “Risale fi Berâhîni a’mâli cedveli’t-takvim- il Zîci Habeş el-Hâsib”, and in his “Devâ’irü‘s-sümût fi’l-usturlâb”, he also examined his two methods on indication of azimuth (the horizontal aspect of direction) on astrolabe (measuring device). İbn Irak’s famous student Birûnî also mentioned Habeş as “hakim”, referring to “ez-Zîcü’l-mümtehan” and mentioning this map in relation to the solution to the “rü’yet-i hilâl” problem, together with the famous map of Bettâni. Bîrûni’s interest on “ez-Zîcü’l-mümtehan” was not limited to this, and he also wrote a separate work titled “Tekmîlü Zîci Habeş bi’l-‘ilel ve tehzîbi a’mâlihî mine’z-zelel”. There is also another map that was directly based on Habeş el-Hâsib’s work, and this was written by Cemâleddin Ebül-Kâsım b Mahfuz el-Müneccim el-Bağdâdi in 1285

The most striking achievement of Habeş can be seen in his application of trigonometric functions to the problems of the global astronomy. In these efforts, following Hârizmî, the first to come up with the sine chart (ceyb meb-sût) in the Islam trigonometry history, he prepared the sine charts for the values 0 = 0: 0°, 0; 15°, 0; 30°, 0; 45°, 1; 0°... 90: 0°, and, to separate sine and “versine”, he used the term “ceyb ma’kûs” for the first time. Furthermore, it can be seen that he went beyond Hârizmî, who had used the term “ceyb menkûs” for “versine”, and he clarified the distinction between these terms.

Habeş el-Hâsib found a new method to estimate time by observing the raise of the sun, and this method was also used by later astronomers. According to this method, at dawn, the sun was on the skyline, with 0 heights, only to increase later on. It was at its peak at noon time and its height gradually decreases, only to disappear at the vanishing point. Therefore, height of the sun gave us the time passed. In his work “Devâir el-Sumut fi el-Usturlab”, Ebu Nasr Mansur b. el-Iraki examined Habeş el-Hâsib’s two original methods about the indication of the azimuth circles on the astrolabe. The “geometrical proposition” Habeş used in this was quite interesting and his method was not used in the later literature.


ez-Zîc alâ mezhebi's-Sindhind, ez-Zîcü'l-müm-tehan, ez-Zîcü'd-Dımaşki. (Sâlih Zeki claimed it was the same work as ez-Zîcü'l-mümte-han.), ez-Zîcü’ş-şağir (also known with the name Zîcü’ş-şâh, could not survive till today), ez-Zîcü’l-Me’mûnî (Sâlih Zeki claimed this work, which could not survive till today, was the same work as ez-Zîcü’l-mümtehan, like ez-Zîcü’d-Dımaşki), Kitâbü Ameli’I-usturlâb, Kitâb fî ma rifeti’l-küre ve’l-‘amel bihâ (About the definition of the sphere and its usage in astronomical observations), Ma’rifetü keyfiyyeti’l-erşâd ve’l-amel bizâti’l-halak (Describes how the astronomy device called “Zâtü’l-halak” should be used).

Besides these, works such as Kitâbü’l-Eb'âd ve’l-ecrâm, Kitâbü’d-Devâ’iri’ş-şelâşi’l-mü-mâsse and keyfiyyeti’l-evşâl, Kitâbü’r-Rahâ im ve’l-makayîs, Kitâbü ‘Ameli’s-sutûhi’l-mebsûta ve’l-ka ime ve’l-mâ and ve’l-münharife are said to have existed, in various sources.


Devamını Gör