Al-Battani: The first scientist to explain solar eclipse

Famous 26 Feb 2021 Tamalika Basu
Today's Focus

It is rather curious that while public memory remembers medieval Islamic contributions to civilization mostly in terms of empire-building, various fields of the arts and monuments, the seminal contributions of Muslim scientists are largely forgotten. Over the next few pieces, I shall discuss in this column lives and works of some of such scientists. Those who turned the course of scientific discourse in their era. Very few of us remember the name Abu Abd Allah Muhammad ibn Jabir ibn Sinan al-Raqqi al-Harrani as-Sabi al-Battani.

Al-Battani and his achievements

In the history of astronomy, he is more popularly known simply as al-Battani in Arabic and Albatenius in Latin. This late 9th-century astronomer in the words of Encyclopaedia Britannica, “…improved Ptolemy’s astronomical calculations by replacing geometrical methods with trigonometry. From 877 CE he carried out many years of remarkably accurate observations at ar-Raqqah in Syria.”

Al-Battani was born in C 858 CE in Harran in present-day’s Turkey. Sometime in 858 CE. Jabir ibn Sinan al-Harrani, his father had attained fame as a scientific instrument maker. It has been claimed that he had princely origins in the Arab world. That, however, has been disputed by many scholars. From 877 CE over the next forty years, al-Battani lived in the ancient city named Raqqa, in Syria. He died in 929 CE in Qasr al-Jiss in today’s Iraq.

In a stunning calculation, he determined that the Solar year as being 365 days, 5 hours, 46 minutes, and 24 seconds. This is just 2 minutes and 24 seconds different from today’s calculation. And al-Battani had arrived at this calculation as early as the late 9th century. That is more than a millennium ago. This great Arab astronomer also made a seminal contribution towards an understanding of how annual solar eclipses occurred. Studying the celestial bodies minutely al-Battani rightly came to the conclusion that when Sun was the furthest from the Earth the solar eclipse occurred. He was the first astronomer in the world to have arrived at this conclusion.

His effort towards Qibla finder

The great astronomer went on to amend many of Ptolemy’s results and compiled new tables of the Sun and Moon, which were accepted for long as accepted as authoritative. It has been found that many of al-Battani’s measurements were more accurate than ones made by Copernicus many centuries. Al-Battan, for example, pointed out that the direction of the Sun’s apogee, which Ptolemy had recorded, was changing. For centuries al-Battani was known to be the most famous among the Arab astronomers in Europe. His fame as well as the importance of his large gamut of astronomical work can be surmised from the fact that Copernicus in his legendary book De Revolutionibus Orbium Coelestium, mentions his name 23 times!

Using his mathematical genius al-Battani also intended to contribute directly to the practice of Islam. He did that by creating an equation that enabled Muslims to find the Qibla, which adheres to Islam. He wanted to find the direction Muslims must face in each of the five prayers every day. However, this over time turned out to be rather inaccurate.

Al-Battani’s famous book is title Kitab az-Zij or ‘The Book of Astronomic Calculations’. He also penned a book titled Arbu Maqalat, or Four Discourses, which is a commentary on Ptolemy’s Quadripartitum de apotelesmatibus e judiciis astrorum.


(Written by Author and Translator Nilanjan Hajra)