Yaʿqūb ibn Ṭāriq

Yaʿqūb ibn Ṭāriq (يعقوب بن طارق; died c. 796 AD) was an 8th-century Persian astronomer and mathematician who lived in Baghdad.

Works

Works ascribed to Yaʿqūb ibn Ṭāriq include:[1]

An astrological work called Al‐maqālāt (المقالات, "The Chapters") is also ascribed to him by an unreliable source.[1]

The Zīj, written around 770, was based on a Sanskrit work,[1] thought to be similar to the Brāhmasphuṭasiddhānta.[2] This work was brought to the court of al-Mansūr from Sindh,[2] reportedly by an Sindhi astronomer named Kankah.[3]

The Tarkīb al‐aflāk dealt with cosmography, that is, the placement and sizes of the heavenly bodies.[1] Its estimates of the sizes and distances of the heavenly bodies were tabulated in al-Bīrūnī's work on India; according to him, Yaʿqūb ibn Ṭāriq gave the radius of the Earth as 1,050 farsakhs, the diameter of the Moon and Mercury as 5,000 farsakhs (4.8 Earth radii), and the diameter of the other heavenly bodies (Venus, the Sun, Mars, Jupiter, and Saturn) as 20,000 farsakhs (19.0 Earth radii.)[4]

Notes

  1. 1 2 3 4 Plofker
  2. 1 2 Pingree, p. 97
  3. Kennedy 1956, p. 134, 71
  4. Pingree, pp. 105–106

Further reading

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