User:Roro1022/Al-Battani

Jabir ibn Sinan al-Harrani was likely this famous instrument maker, although this is not something that has been proven.

Although his ancestors were likely of the Sabian-sect, he is a Muslim, as his name is Muhammad, with his kunya being Abu Abd Allah.

He died at Qasr al-Jiss, which is located near Samarra, Iraq. He was returning from Baghdad to al-Raqqa after resolving a dispute on behalf of the people of al-Raqqa.

Another of al-Battānī's accomplishments is that he concluded how an annular solar eclipse occurs. He did this by observing that the radius between the Earth and the Sun changes throughout the year. This led him to arrive to the conclusion that when the Sun is farthest from the Earth, an annular solar eclipse occurs. He was the first to make this observation and inference.

He also influenced Jewish rabbis and philosophers such as Abraham ibn Ezra, Abraham bar Hiyya, and Maimonides.

Using these trigonometrical relationships, Al-Battānī created an equation for finding the qibla, which Muslims must face in each of the five prayers they practice everyday. The equation he created did not give accurate directions, as it did not take into account the fact that Earth is a sphere. The relationship Al-Battānī used was fairly precise when a person is in Mecca, or close to Mecca, but resulted in more and more inaccurate results as one gets more distant from Mecca. However, it was still a widely used method at the time. The equation is as follows:

$$\alpha=\arctan\frac{\sin\Delta\lambda}{\sin\Delta\phi}$$

The word zij is a Persian word that was used to describe a rug warp.