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Habash al-Hasib

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Persian polymath (died c. 869 CE)
Habash al-Hasib
حبش الحاسب
BornAhmad 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, known as Habash al-Hasib (Persian: حبش الحاسب, lit.'Abyssinian calculator', died c. 869) was a Persian astronomer, 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.

Habash al-Hasib flourished in Baghdad, and died a centenarian some time between 864–874 possibly in Abbasid Samarra. The title "Habash" (Abbyssian) may refer to dark skin coulor. 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.

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 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.

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

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

Notes

  1. ^ Kennedy, Edward Stewart (1956). A Survey of Islamic Astronomical Tables. American Philosophical Society. ISBN 978-0-87169-462-1.
  2. ^ "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. ^ Hartner, W (2012). "Ḥabas̲h̲ al-Ḥāsib al-Marwazī". referenceworks. doi:10.1163/1573-3912_islam_sim_2572. Retrieved 2024-11-07.
  4. ^ 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. ^ 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 , Bibcode:1985Cent...28..108T, doi:10.1111/j.1600-0498.1985.tb00831.x

References

External links

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