07-24-2004, 07:57 AM
Ibn Yunus (399 A.H. / 1009 A.D.)
- His Birth and Early Life:
- His name is Abu Al-Hasan bin `Abdul-Rahman bin Ahmad bin Yunus bin `Abd Al-A`la.
- He was born in Egypt in a respected family in Fustat, his great grandfather having been a companion of the famous legal scholar Al-Sahfi`i and his father being a distinguished historian and scholar of hadith.
- Since his childhood, Ibn Yunus received knowledge. Due to Ibn Yunus’ excellence in astronomy, Al-`Aziz Billah the Fatimid and his son Al-Hakim Bi’amr Allah encouraged him to proceed in his researches in astronomy and mathematics. They dedicated for him an observatory on the peak of Al-Muqattam hills near Cairo, which was equipped with the most modern observation tools.
- Ibn Yunus managed to observe the solar and lunar eclipses in 368 A.H. / 978 A.D.
- He reached the same results discovered by the astronomers of Baghdad. His astronomical tables were distinguished with meticulous calculations and attention to detail, what made them a reference to all later scientists.
- Important Achievements:
- He observed the solar eclipses in the years 368 A.H. / 977 A.D. and 369 A.H./ 978 A.D. These were the first eclipses to be reliably and accurately recorded in a scientific way.
- He determined the secular acceleration of the moon.
- He corrected many theories regarding the inclination of the zodiac, the atmospheric refraction of the sun’s rays and the equinox.
- He managed to resolve many intricate questions of astrometry.
- He was the first to consider secondary parentheses as an alternative of square roots that render mathematical questions very intricate.
- He contributed to making trigonometry as a separate science from astronomy.
- He initiated the tables of tangents and cotangents.
- He invented a new method to facilitate mathematical operations.
- The most important of his inventions was the pendulum.
- Ibn Yunus dedicated all his life in studying and observing the motion of planets.
- Among the most important works of Ibn Yunus in astronomy and mathematics are the following:
- Al-Zij Al-Hakimi (four volumes)
- Kitab Al-Zhill
- Ghayat Al-Intifa`
- Kitab Al-Mail
- Al-Ta`dil Al-Muhkam
- Al-Raqqas
- Tarikh A`yan Misr