Habash al-Hasib
{{Short description|Persian polymath (died c. 869 CE)}}
{{Infobox scientist
| name = Habash al-Hasib
| native_name = حبش الحاسب
| native_name_lang = fa
| birth_name = Ahmad ibn ‘Abdallah al-Marwazi
| birth_place = Merv, Abbasid Caliphate
| death_date = Between 864–874 (aged 100)
| death_place = Possibly in Abbasid Samarra, Abbasid Caliphate
| other_names =
| known_for = tangent and cotangent, Kepler's equation
| children = Abu Ja'far ibn Habash
| fields = Astronomy
}}
Ahmad ibn 'Abdallah al-Marwazi,{{Cite book |last=Kennedy |first=Edward Stewart |url=https://books.google.com/books?id=EywLAAAAIAAJ&q=%22Ahmad+ibn+Abdallah+al-Marwazi%22+habash+al-hasib |title=A Survey of Islamic Astronomical Tables |date=1956 |publisher=American Philosophical Society |isbn=978-0-87169-462-1 |language=en}} known as Habash al-Hasib ({{Langx|fa|حبش الحاسب|4=Abyssinian calculator}},{{Cite journal |last=Hartner |first=W |date=2012 |title=Ḥabas̲h̲ al-Ḥāsib al-Marwazī |url=https://referenceworks.brill.com/display/entries/EIEO/SIM-2572.xml |access-date=2024-11-07 |website=referenceworks |language=en |doi=10.1163/1573-3912_islam_sim_2572}} died {{circa}} 869{{sfn|Charette|2007}}) was a Persian[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"{{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 }} astronomer,Islamic Desk Reference, ed. E. J. Van Donzel, (Brill, 1994), 121. geographer, and mathematician from Merv in Khorasan, who discovered the trigonometric ratios tangent, and cotangent.{{Cite web |date=2025-02-07 |title=Trigonometry - India, Islamic World {{!}} Britannica |url=https://www.britannica.com/science/trigonometry/India-and-the-Islamic-world |access-date=2025-02-14 |website=www.britannica.com |language=en|quote= The first table of tangents and cotangents was constructed around 860 by Ḥabash al-Ḥāsib (“the Calculator”), who wrote on astronomy and astronomical instruments.}} Al-Biruni who cited Habash in his work, expanded his astronomical tables.
Habash al-Hasib flourished in Baghdad, and died a centenarian some time between 864 and 874{{Cite book |last=Selin |first=Helaine |url=https://books.google.com/books?id=GzjpCAAAQBAJ&dq=Habash+al-Hasib&pg=PA392 |title=Encyclopaedia of the History of Science, Technology, and Medicine in Non-Westen Cultures |date=2013-11-11 |publisher=Springer Science & Business Media |isbn=978-94-017-1416-7 |language=en}} possibly in Abbasid Samarra.{{sfn|Charette|2007}} The title "Habash" (Abbyssian) may refer to dark skin color. He worked under two Abbasid caliphs, al-Ma'mun and al-Mu'tasim.
Habash al-Hasib developed a trigonometric algorithm to solve problems related to parallax, which was later rediscovered by Johannes Kepler in 1609 and it is now known as Kepler's equation.{{Cite book |last=Livingston |first=John W. |url=https://books.google.com/books?id=clcPEAAAQBAJ&dq=al+hasib+Kepler%27s+equation&pg=PA163 |title=The Rise of Science in Islam and the West: From Shared Heritage to Parting of The Ways, 8th to 19th Centuries |date=2017-12-14 |publisher=Routledge |isbn=978-1-351-58926-0 |language=en}}{{Cite book |last=North |first=John |url=https://books.google.com/books?id=qq8Luhs7rTUC&dq=al+hasib+Kepler%27s+equation&pg=PA357 |title=Cosmos: An Illustrated History of Astronomy and Cosmology |date=2008-07-15 |publisher=University of Chicago Press |isbn=978-0-226-59441-5 |language=en}}
Habash is the father of the astronomer Abu Ja'far ibn Habash.
Work
Habash Hasib made astronomical observations from 825 to 835, and compiled three zijes (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 860, he seems to have introduced the notion of "shadow", umbra (versa), equivalent to our tangent in trigonometry, and he compiled a table of such shadows which seems to be the earliest of its kind. He also introduced the cotangent, and produced the first tables of for it.{{cite encyclopedia|title=trigonometry|url=http://www.britannica.com/EBchecked/topic/605281/trigonometry|encyclopedia=Encyclopædia Britannica|access-date=2008-07-21}}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}}
=''The Book of Bodies and Distances''=
Habash al-Hasib conducted various observations at the Al-Shammisiyyah observatory in Baghdad and estimated a number of geographic and astronomical values. He compiled his results in The Book of Bodies and Distances ({{Transliteration|ar|Kitāb al-ajrām wa-l-ab 'ād}}), in which some of his results included the following:{{citation|doi=10.1111/j.1600-0498.1985.tb00831.x|title=The Book of Bodies and Distances of Habash al-Hasib|last=Langermann|author-link=Tzvi Langermann|first=Y. Tzvi|journal=Centaurus|year=1985|volume=28|issue=2|pages=108–128 [111]|bibcode=1985Cent...28..108T}}
;Earth
- Earth's circumference: 20,160 miles (32,444 km)
- Earth's diameter: 6414.54 miles (10323.201 km)
- Earth radius: 3207.275 miles (5161.609 km)
;Moon
- Moon's diameter: 1886.8 miles (3036.5 km)
- Moon's circumference: 5927.025 miles (9538.622 km)
- Radius of closest distance of Moon: 215,208;9,9 (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 km)
- Circumference of furthest distance of Moon: 1,293,600.916 miles (2,081,848.873 km)
;Sun
- Sun's diameter: 35,280;1,30 miles (56,777.6966 km)
- Sun's circumference: 110,880;4,43 miles (178,444.189 km)
- Diameter of orbit of Sun: 7,761,605.5 miles (12,491,093.2 km)
- Circumference of orbit of Sun: 24,392,571.38 miles (39,256,038 km)
- One degree along orbit of Sun: 67,700.05 miles (108,952.67 km)
- One minute along orbit of Sun: 1129.283 miles (1817.405 km)
See also
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}}
{{People of Khorasan}}
{{Authority control}}
{{DEFAULTSORT:Habash}}
Category:9th-century Iranian mathematicians
Category:Scientists who worked on qibla determination
Category:9th-century Iranian astronomers
Category:Year of birth unknown
Category:Iranian men centenarians