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Habash al-Hasib

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Habash al-Hasib
حبش الحاسب
Born
Ahmad ibn ‘Abdallah al-Marwazi

Merv, Abbasid Caliphate
DiedBetween 864–874 (aged 100)
Possibly in Abbasid Samarra, Abbasid Caliphate
Known forKepler's equation
ChildrenAbu Ja'far ibn Habash
Scientific career
FieldsAstronomy

Ahmad ibn 'Abdallah al-Marwazi,[1][2] known as Habash al-Hasib (Persian: حبش الحاسب, lit. 'Abyssinian calculator',[1][2][3] died c. 869[4]) was a Persian[5][2] astronomer,[6] geographer, and mathematician from Merv in Khorasan, who was the first to describe the trigonometric ratios tangent, and cotangent. Al-Biruni who cited Habash in his work, expanded his astronomical tables.[3]

Habash al-Hasib flourished in Baghdad, and died a centenarian some time between 864 and 874[2][3][7] possibly in Abbasid Samarra.[4] The title "Habash" (Abbyssian) may refer to dark skin color.[3] He worked under two Abbasid caliphs, al-Ma'mun and al-Mu'tasim.[3]

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.[8][9]

Habash is the father of the astronomer Abu Ja'far ibn Habash.[3]

Work

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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 830, 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.[10][11]

The Book of Bodies and Distances

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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 (Kitāb al-ajrām wa-l-ab 'ād),[7] in which some of his results included the following:[12]

Earth
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

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Notes

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  1. ^ a b Kennedy, Edward Stewart (1956). A Survey of Islamic Astronomical Tables. American Philosophical Society. ISBN 978-0-87169-462-1.
  2. ^ a b c d "Archived copy" (PDF). Archived from the original (PDF) on 2013-10-07. Retrieved 2013-09-04.{{cite web}}: CS1 maint: archived copy as title (link)
  3. ^ a b c d e f Hartner, W (2012). "Ḥabas̲h̲ al-Ḥāsib al-Marwazī". referenceworks. doi:10.1163/1573-3912_islam_sim_2572. Retrieved 2024-11-07.
  4. ^ a b Charette 2007.
  5. ^ General Cartography Archived 2017-12-09 at the Wayback Machine : "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"
  6. ^ Islamic Desk Reference, ed. E. J. Van Donzel, (Brill, 1994), 121.
  7. ^ a b Selin, Helaine (2013-11-11). Encyclopaedia of the History of Science, Technology, and Medicine in Non-Westen Cultures. Springer Science & Business Media. ISBN 978-94-017-1416-7.
  8. ^ Livingston, John W. (2017-12-14). The Rise of Science in Islam and the West: From Shared Heritage to Parting of The Ways, 8th to 19th Centuries. Routledge. ISBN 978-1-351-58926-0.
  9. ^ North, John (2008-07-15). Cosmos: An Illustrated History of Astronomy and Cosmology. University of Chicago Press. ISBN 978-0-226-59441-5.
  10. ^ "trigonometry". Encyclopædia Britannica. Retrieved 2008-07-21.
  11. ^ Jacques Sesiano, "Islamic mathematics", p. 157, in Selin, Helaine; D'Ambrosio, Ubiratàn, eds. (2000), Mathematics Across Cultures: The History of Non-western Mathematics, Springer, ISBN 1-4020-0260-2
  12. ^ Langermann, Y. Tzvi (1985), "The Book of Bodies and Distances of Habash al-Hasib", Centaurus, 28 (2): 108–128 [111], Bibcode:1985Cent...28..108T, doi:10.1111/j.1600-0498.1985.tb00831.x

References

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