Al-Kachi

Al-Kachi or Al-Kashi (" the native of Kashan "), of its complete name Ghiyath AD-DIN Jamshid Farmhouse `ud Al-Kashi ( ghiyâth AD-DIN : " help of the religion" , farmhouse `ûd : " heureux" , ĵamšid : " Yama the brillant" in Persan), Mathematician and Persian Astronomer (towards 1380, Kashan (Iran) - 1429, Samarkand (Ouzbékistan)).

Biography

It assisted with a moon eclipse in 1406 with Kashan and wrote several astronomical works in the following years. Its Khaqani zij (tables of large the khan) was dedicated to Shah Rukh or Oulough Beg.

Oulough Beg invited Al-Kashi with Samarkand in 1420, year of the opening of the Médersa which bears its name. Al-Kachi taught there with Qadi-zadeh Roumi, the professor of Oulough Beg, and probably Oulough Beg itself.

Al-Kachi played a big role in the design of the observatory of Samarkand, inaugurated towards 1429, and of its instruments of astronomy. Previously, the observations of the sky were carried out with the Médersa.

The work undertaken by Oulough Beg, Qadi-zadeh Roumi, Al-Kachi and some sixty other scientists led to the publication of the Tables sultaniennes ( zij-E solTâni , in Persan), published in 1437 but improved by Oulough Beg until little before its death in 1449. The data of the Khaqani zij were of course used there.

Written letters in Persan by Al-Kachi with his/her father at that time describe in detail the scientific life with Samarkand. Only Qadi-zadeh Roumi and Oulough Beg finds thanks to its eyes. Al-Kachi was of a little refined temperament, but Oulough Beg treated it with benevolence because of its competences.

Al-Kachi calculated the number π with an accuracy of fifteen decimals, which was to remain unequalled during nearly two centuries.

Sources

See too

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  • Theorem of Al-Kashi

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