View source for Biography:Habash al-Hasib al-Marwazi

{{short description|Astronomer, Mathematician and geographer}}
'''Ahmad ibn 'Abdallah Habash Hasib Marwazi''' (766 - d. after 869 in [[Place:Samarra|Samarra]], Iraq{{sfn|Charette|2007}} ) was a Persian<ref>[http://www.eiilmuniversity.co.in/downloads/General_Cartography.pdf/ General Cartography] {{Webarchive|url=https://web.archive.org/web/20171209210029/http://www.eiilmuniversity.co.in/downloads/General_Cartography.pdf |date=2017-12-09 }} : "The Iranian geographers Abū Muhammad al-Hasan al-Hamdānī and Habash al-Hasib al-Marwazi set the Prime Meridian of their maps at Ujjain, a center of Indian astronomy"</ref><ref>[https://www.coursehero.com/file/p173a472/Additionally-in-the-ninth-century-the-Persian-mathematician-and-geographer/] : "Additionally in the ninth century, the Persian mathematician and geographer, Habash al-Hasib al-Marwazi, utilized the utilization circular trigonometry and guide projection strategies keeping in mind the end goal to change over polar directions to an alternate arrange framework fixated on a particular point on the circle, in this the Qibla, the course to Mecca. Abū Rayhān Bīrūnī (973– 1048) later created thoughts which are viewed as a reckoning of the polar organize framework."</ref><ref>{{cite web |url=http://www.usc.edu/schools/college/crcc/private/cmje/heritage/History_of_Islamic_Science.pdf |title=Archived copy |access-date=2013-09-04 |url-status=dead |archive-url=https://web.archive.org/web/20131007200209/http://www.usc.edu/schools/college/crcc/private/cmje/heritage/History_of_Islamic_Science.pdf |archive-date=2013-10-07 |df= }}</ref> astronomer,<ref>''Islamic Desk Reference'',  ed. E. J. Van Donzel, (Brill, 1994), 121.</ref> geographer, and mathematician from [[Place:Merv|Merv]] in [[Place:Greater Khorasan|Khorasan]] who for the first time described the trigonometric ratios: [[Sine|sine]], [[Cosine|cosine]], [[Tangent|tangent]] and [[Cotangent|cotangent]].

He flourished in [[Place:Baghdad|Baghdad]], and died a centenarian after 869. He worked under the Abbasid caliphs al-Ma'mun and al-Mu'tasim.

==Work==
He made observations from 825 to 835, and compiled three astronomical tables: the first were still in the Hindu manner; the second, called the 'tested" tables, were the most important; they are likely identical with the "Ma'munic" or "Arabic" tables and may be a collective work of al-Ma'mun's  astronomers; the third, called tables of the Shah, were smaller.

Apropos of the solar eclipse of 829, Habash gives us the first instance of a determination of time by an altitude (in this case, of the sun); a method  which was generally adopted by Muslim astronomers.

In 830, he seems to have introduced the notion of  "shadow", umbra (versa), equivalent to our [[Trigonometric functions|tangent]] in [[Trigonometry|trigonometry]], and he compiled a table of such shadows which seems to be the earliest of its kind. He also introduced the [[Trigonometric functions|cotangent]], and produced the first tables of for it.<ref name=trigonometry>{{cite encyclopedia|title=trigonometry|url=http://www.britannica.com/EBchecked/topic/605281/trigonometry|encyclopedia=[[Encyclopædia Britannica]]|accessdate=2008-07-21}}</ref><ref name=Sesiano>Jacques Sesiano, "Islamic mathematics", p. 157, in {{citation|title=Mathematics Across Cultures: The History of Non-western Mathematics|editor1-first=Helaine|editor1-last=Selin|editor1-link=Helaine Selin|editor2-first=Ubiratàn|editor2-last=D'Ambrosio|editor2-link=Ubiratàn D'Ambrosio|year=2000|publisher=Springer|isbn=1-4020-0260-2|postscript=<!--none-->}}</ref>

===''The Book of Bodies and Distances''===
Al-Hasib conducted various observations at the Al-Shammisiyyah observatory in [[Place:Baghdad|Baghdad]] and estimated a number of geographic and astronomical values. He compiled his results in ''The Book of Bodies and Distances'', in which some of his results included the following:<ref>{{citation|doi=10.1111/j.1600-0498.1985.tb00831.x|title=The Book of Bodies and Distances of Habash al-Hasib|last=Langermann|first=Y. Tzvi|journal=Centaurus|year=1985|volume=28|issue=2|pages=108–128 [111]|postscript=<!--none-->|bibcode=1985Cent...28..108T}}</ref>

;Earth
*Earth's [[Circumference|circumference]]: 20,160 miles (32,444&nbsp;km)
*Earth's [[Diameter|diameter]]: 6414.54 miles (10323.201&nbsp;km)
*[[Astronomy:Earth radius|Earth radius]]: 3207.275 miles (5161.609&nbsp;km)

;Moon
*Moon's diameter: 1886.8 miles (3036.5&nbsp;km)
*Moon's circumference: 5927.025 miles (9538.622&nbsp;km)
*Radius of closest distance of Moon: 215,208;9,9 ([[Sexagesimal|sexagesimal]]) miles
*Half-circumference of closest distance of Moon: 676,368;28,45,25,43 (sexagesimal) miles
*[[Radius]] of furthest distance of Moon: 205,800;8,45 (sexagesimal) miles
*Diameter of furthest distance of Moon: 411,600.216 miles (662,406.338&nbsp;km)
*Circumference of furthest distance of Moon: 1,293,600.916 miles (2,081,848.873&nbsp;km)

;Sun
*Sun's diameter: 35,280;1,30 miles (56,777.6966&nbsp;km)
*Sun's circumference: 110,880;4,43 miles (178,444.189&nbsp;km)
*Diameter of orbit of Sun: 7,761,605.5 miles (12,491,093.2&nbsp;km)
*Circumference of orbit of Sun: 24,392,571.38 miles (39,256,038&nbsp;km)
*One [[Degree (angle)|degree]] along orbit of Sun: 67,700.05 miles (108,952.67&nbsp;km)
*One minute along orbit of Sun: 1129.283 miles (1817.405&nbsp;km)

==See also==
*List of Muslim scientists
*List of pre-modern Iranian scientists and scholars

==Notes==
{{Reflist}}

==References==
* {{cite encyclopedia | editor = Thomas Hockey| last = Charette | first = François | title=Ḥabash al‐Ḥāsib: Abū Jaʿfar Aḥmad ibn ʿAbd Allāh al‐Marwazī | encyclopedia = The Biographical Encyclopedia of Astronomers | publisher = Springer | date = 2007 | location = New York | pages = 455–7 | url=http://islamsci.mcgill.ca/RASI/BEA/Habash_al-Hasib_BEA.htm | isbn=978-0-387-31022-0|display-editors=etal}} ([http://islamsci.mcgill.ca/RASI/BEA/Habash_al-Hasib_BEA.pdf PDF version])

==External links==
*''[https://archive.org/details/handbuchdergesch00ibnquoft Handbuch der Geschichte : aus den Handschriften der k.k. Hofbibliothek zu Wien, der herzoglichen Bibliothek zu Gotha und der Universitäts-Bibliothek zu Leyden (1850)]'', ed.: Ferdinand Wüstenfeld
*''[https://archive.org/details/extractfromibnku00ibnquoft An extract from Ibn Kutaiba's 'Adab al-Kâtib; or, The writer's guide (1877)]'', ed.: William Oliver Sproull
*''[https://archive.org/details/ibnkutaibasadaba00ibnquoft Ibn Kutaiba's Adab-al-kâtib. Nach mehreren Handschriften hrsg. von Max Grünert (1900)]'', ed.: Max Grünert
*''[https://archive.org/details/liberpoesisetpoe00ibnq  Liber poesis et poetarum (1904)]'', ed.: Michael Jan de Goeje

{{Islamic mathematics}}
{{Islamic astronomy}}

{{DEFAULTSORT:Habash Al-Hasib Al-Marwazi}}
[[Category:9th-century mathematicians]]

{{Sourceattribution|Habash al-Hasib al-Marwazi|1}}