Ahmad ibn 'Abdallah al-Marwazi, died 869) was a Persian astronomer, geographer, and mathematician from Merv in Khorasan, who discovered the trigonometric ratios tangent, and cotangent. Al-Biruni who cited Habash in his work, expanded his astronomical tables. possibly in Abbasid Samarra. The title "Habash" (Abbyssian) may refer to dark skin color.

Habash al-Hasib is the father of the astronomer Abu Ja'far ibn Habash.

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 (),

;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

  • List of Muslim scientists
  • List of pre-modern Iranian scientists and scholars

Notes

References

  • (PDF version)
  • 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
  • An extract from Ibn Kutaiba's 'Adab al-Kâtib; or, The writer's guide (1877), ed.: William Oliver Sproull
  • Ibn Kutaiba's Adab-al-kâtib. Nach mehreren Handschriften hrsg. von Max Grünert (1900), ed.: Max Grünert
  • Liber poesis et poetarum (1904), ed.: Michael Jan de Goeje