View source for Biography:Yaʿqūb ibn Ṭāriq

'''Yaʿqūb ibn Ṭāriq''' ({{lang|ar|يعقوب بن طارق}}; died c. 796 AD) was an 8th-century Persian [[Astronomy:Astronomer|astronomer]] and [[Biography:Mathematician|mathematician]] who lived in [[Place:Baghdad|Baghdad]].
== Works ==
Works ascribed to Yaʿqūb ibn Ṭāriq include:<ref name=bea>Plofker</ref>
* ''Zīj maḥlūl fī al‐Sindhind li‐daraja daraja'' ({{lang|ar|زيج محلول في السندهند لدرجة درجة}}, "Astronomical tables in the ''Sindhind'' resolved for each degree"),
* ''Tarkīb al‐aflāk'' ({{lang|ar|تركیب الأفلاك}}, "Arrangement of the orbs"),
* ''Kitāb al‐ʿilal'' ({{lang|ar|كتاب العلل}}, "Rationales"),
* ''Taqṭīʿ kardajāt al‐jayb'' ({{lang|ar|تقطيع كردجات الجيب}}, "Distribution of the ''kardajas'' of the sine"), and
* ''Mā irtafaʿa min qaws niṣf al‐nahār'' ({{lang|ar|ما إرتفع من قوس نصف النهار}}, "Elevation along the arc of the meridian").
An astrological work called ''Al‐maqālāt'' ({{lang|ar|المقالات}}, "The Chapters") is also ascribed to him by an unreliable source.<ref name=bea />

The ''[[Astronomy:Zij|Zīj]]'', written around 770, was based on a Sanskrit work,<ref name=bea /> thought to be similar to the ''[[Religion:Brāhmasphuṭasiddhānta|Brāhmasphuṭasiddhānta]]''.<ref name=pingree97>Pingree, p. 97</ref>  This work was brought to the court of al-Mansūr from Sindh,<ref name=pingree97 /> reportedly by a Sindhi astronomer named Kankah.<ref name=kennedy>Kennedy 1956, p. 134, '''71'''</ref>

The ''Tarkīb al‐aflāk'' dealt with cosmography, that is, the placement and sizes of the heavenly bodies.<ref name=bea />  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.)<ref>Pingree, pp. 105–106</ref>

==Notes==
{{Reflist|30em}}

== Further reading ==
* {{cite journal|last=Hogendijk|first=Jan P.|date=1988|title=New Light on the Lunar Crescent Visibility Table of Yaʿqūb ibn Ṭāriq|journal=Journal of Near Eastern Studies|volume=47|issue=2|doi=10.1086/373260|pages=95–104|jstor=544381}}
* {{cite journal|last=Kennedy|first=E. S.|date=1956|title=A Survey of Islamic Astronomical Tables|journal=Transactions of the American Philosophical Society |series=New Series | volume=46 | issue=2 | pages=123–177 | jstor=1005726 |doi=10.2307/1005726 |hdl=2027/mdp.39076006359272 |hdl-access=free }}
* {{cite journal|last=Kennedy|first=E. S.|date=1968|title=The Lunar Visibility Theory of Yaʿqūb Ibn Ṭāriq|journal=Journal of Near Eastern Studies|volume=27|issue=2|doi=10.1086/371945|pages=126–132|jstor=543759}}
* {{cite journal|last=Pingree|first=David|date=1968|title=The Fragments of the Works of Yaʿqūb Ibn Ṭāriq|journal=Journal of Near Eastern Studies|volume=27|issue=2|doi=10.1086/371944|pages=97–125|jstor=543758}}
* {{cite encyclopedia
  | last = Pingree
  | first = David
  | title = Yaʿqūb ibn Ṭāriq
  | encyclopedia = Dictionary of Scientific Biography
  | volume = 14
  | pages = 546
  | editor = Gillispie, Charles Coulston
  | publisher = Charles Scribner's Sons
  | location = New York
  | date = 1976
  | isbn = 978-0-684-16962-0
  | url = http://www.encyclopedia.com/doc/1G2-2830904745.html
 }}
* {{cite encyclopedia | editor = Thomas Hockey | display-editors = etal | last = Plofker | first = Kim | title=Yaʿqūb ibn Ṭāriq | encyclopedia = The Biographical Encyclopedia of Astronomers | publisher = Springer | date = 2007 | location = New York | pages = 1250–1 | url=http://islamsci.mcgill.ca/RASI/BEA/Yaqub_ibn_Tariq_BEA.htm | isbn=978-0-387-31022-0}} ([http://islamsci.mcgill.ca/RASI/BEA/Yaqub_ibn_Tariq_BEA.pdf PDF version])
* [[Biography:Fuat Sezgin|Sezgin, Fuat]] (1978). ''Geschichte des arabischen Schrifttums''. Vol. '''6''', ''Astronomie'', pp.&nbsp;124&ndash;127. Leiden: E. J. Brill.
* {{cite journal|last=Steinschneider|first=Moritz|date=1870|title=Zur Geschichte der Uebersetzungen aus dem Indischen in's Arabische und ihres Einflusses aus die arabische Literatur|journal=Zeitschrift der Deutschen Morgenländischen Gesellschaft|volume=24|pages=332|url=http://menadoc.bibliothek.uni-halle.de/dmg/periodical/titleinfo/21506}}
* {{cite book|last=Suter|first=Heinrich|title=Die Mathematiker und Astronomer der Araber|date=1900|page=4}}

{{Islamic astronomy}}
{{Islamic mathematics}}


{{DEFAULTSORT:Yaqub Tariq}}
[[Category:8th-century mathematicians]]

{{Sourceattribution|Yaʿqūb ibn Ṭāriq|1}}