Recently, i read an article about the arabic culture. Even if Now, arab are sometimes ascociated to evil (According to The oppressor and its proponents), we still keep in mind that we were pretty good in astronomy, mathematics, medicine and organistation. I would like to introduce for the second time in this blog, a relative of mine whose name's not often quoted while people speak about toledan tables or the Astrolabe or both of them:

"Abu Ishaq Ibrahim ibn Yahya al-Zarqali, known in the West as Arzachel, was a Spanish Arab. He was the foremost astronomer of his time.

Al-Zarqali carried out a series of astronomical observations at Toledo (Arabic Al Tulaytalah) and compiled them in what is known as his famous Toledan Tables. He corrected the geographical data from Ptolemy and Al-Khwarizmi. Specifically, Al-Zarqali corrected Ptolemy's estimate of the length of the Mediterranean sea from 62 degrees to approximately correct value of 42 degrees. The Toledo Tables were translated into Latin in the Twelfth century.

Al-Zarqali was the first to prove conclusively the motion of the Aphelion relative to the stars. He measured its rate of motion as 12.04 seconds per year, which is remarkably close to the modern calculation of 11.8 seconds. Al-Zarqali invented a flat astrolabe which is known as Safihah. Its details were published in Latin, Hebrew and several European languages.

Copernicus in his famous book 'De Revolutionibus Orbium Clestium' expresses his indebtedness to al-Battani (albategnius) and Al-Zarqali (Arzachel)".

by
Dr. A. Zahoor