Ibn Al-Shater was among the select group of geniuses in astronomy. He learned the art of ivory inlaying when he was a small boy and was, therefore, known as Al-Mottaem (the inlayer). He also collected an immense amount of money, which allowed him the freedom to concentrate on scientific research, and on wandering round the countries of the Islamic world.
He was occupied with mathematics, but particularly excelled at astronomy, for in this science, he could work on his inventions and build on his scientific achievements. He made an instrument that enabled people to calculate the daily times of the prayers, and called it al-Basseet (the compass). This instrument was placed in an Umayyad mosque in Damascus. He also adjusted the then-existing sundials in Egypt and Syria.
The workings of his astonishing mind were demonstrated when he measured the inclination of the zodiac, and concluded in his researches that it is 23 degrees and 31 minutes. This may be compared to the result that modern astronomers arrived at: 23 degrees 31 minutes and 19.8 seconds, a result that was reached with the aid of computers.
He also corrected Ptolemy's theory, which states that the earth is the center of the universe and not the sun, although modern scientists attribute this theory to Copernicus. One of his works is Nehayyat Al Sool fi Tass-heeh Al Oussool (Final Conclusion on the Origins); a thesis on the astrolabe, the quadrant, and the square.
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