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20 January 2017
13 July 2015

Arabic astronomy

Arabic astronomy

Many scientists of the Arab Islamic civilization were specializing in astronomy and the related to it fields of mathematics. Their big part in its development is that they managed not to only develop it as a science, but also preserve and revise the Greek legacy with the outstanding works of Aristotle and Ptolemy. The Arabs tended to name their works “Almagest” (“Megiste”) in honour of Ptolemy work which included a complete set of astronomic knowledge.

Ptolemy lived in between A.D. 100-170. Although he is believed to have been born in Egypt, he wrote his works in Greek. In his famous work which the Arabs called “Almagest” (big book), he briefly summarized all the achievements made in astronomy at that point.

It all started in Khorasan

Islamic astronomer Abu al-Wafa al-Buzjani wrote his great work “Magiste” in the 4th century Hijrah. The scientist was called Abu al-Wafa, but his full name is Muḥammad ibn Muḥammad ibn Yaḥya ibn Ismail ibn al-ʿAbbas al-Buzjani. He was born in Buzhgan which was the capital of Khorasan and a small settlement between Gerat and Nishapur. Nowadays, most part of this area belongs to Iran. One of the most prominent poets Omar Khayyam was born in Nishapur too. Interestingly, he also had profound knowledge of mathematics. Many astronomers and mathematicians of the Arab Islamic civilization are from Korasan. Muḥammad ibn Musa al-Khwarizmi is one of the most prominent among them. He is considered to be the founder of algebra.

Abu al-Wafa was born in A.D. 940. He was brought up in the family of scientists. The brothers of his parents were famous mathematicians: Amr al-Mughazali and Abu Abdullah ibn Anbas. His teachers of geometry were Abu Yahya al-Mawridi and Abu Ala ibn Karniba. They introduced him to Al-Battani works on astronomy. Before he reached the age of 20, Abu al-Wafa moved to Baghdad and spent all his life there. He died at the age of 58.

When the science flourished

Al-Buzjani’s “Almagest” covers three fields such as trigonometry; astronomic devices and theoretical astronomy. The book was properly appreciated in 2005 when Dr. Ali Musa made his dissertation on science history. The paper was made under the supervision of the famous historian of Arabic culture Roshdi Rashed and presented at Paris University VII (Sorbonne). Following this, the book “Almagest of Abu al-Wafa al-Buzjani” was published by the Centre for Arab unity studies.

At the very beginning of the book, Rashed declares that the scientists of the 3rd century Hijrah made significant achievements in mathematics and astronomy. Most of the discoveries were made on the basis of the observations in Damascus and Baghdad. The scientists not only revised previously made discoveries, but also made some new ones. This was partly dictated by the traditions and needs of the time. For instance, they needed to determine the start of a new month, the qibla direction so that to perform their prayers or the most remote point, etc.

The section about trigonometry seems to deserve a special attention. According to it, there is a significant difference between astronomic and mathematical evidence of the modern science and the evidence presented in “Almagest”. However, Musa declared that most of the trigonometry laws which are currently taught in secondary schools refer to the works of Abu al-Wafa, his expertise and the method by which the Arabs studied trigonometry.

Generally speaking, trigonometry studies relationships involving lengths and angles of triangles. It helps to determine crosscuts and distances between the most remote points, no matter how enormous the distances are.

The second chapter of the book focuses on the astronomic devices which Al-Buzjani invented to study the distant objects, their contents, shapes and trajectory. The third chapter is about the research made in theoretical astronomy. One can see that the works of the Greek scientists, Ptolemy in particular, influenced Al-Buzjani greatly. The Arabic astronomer accepted the main Greek assumption that the Earth is the centre of the universe and all other planets and stars revolve around the Earth. Apparently, this approach is not scientific at present.

Yet, Al-Buzjani made something else which of a great historic significance. He drew a map of the starry sky as seen through the eyes of an Earth observer. This can be considered as a kind of a discovery that he made in the field of stars and space study.

It is worth saying that Abu al-Wafa al-Buzjani “Almagest” reminds us of an incremental progress of science. Everybody is to make his or her own contribution in its development. The book encourages us to always improve and not to focus a lot on the past, but be ready for the future.