Arabic astronomers
Astronomy has always been very important in Arabic countries for three reasons: 1) because the Islamic calendar is based on the movement of the moon; 2) because every day Muslims must say prayers at certain times depending on the position of the sun; 3) because all prayers must be said facing the direction of Mecca. All of these things need astronomers who know the maths of how the sun, the moon and the stars move in the sky. Because the maths of astronomy is so important in Islamic countries many observatories were built, lots of research was done, and many mathematical astronomy books were written.

One of the largest observatories in Islamic countries was built in Istanbul in 1575 for the astronomer Taqi al-Din. After observing a new comet in the sky, Taqi al-Din told the Sultan that he was going to win many battles. Unfortunately Taqi al-Din was wrong and his observatory was demolished after only five years. Another big observatory was built in 1259 at Maragheh in northern Iran for the astronomer Nasir al-Din al-Tusi. In Samarkand in Central Asia an observatory was built in 1420 by Ulugh Beg who was the governor of Samarkand as well as a keen astronomer. The Samarkand observatory was filled with many huge astronomical instruments capable of making very accurate measurements of the positions of the stars.

Arabic astronomers are important because they were the first people to study the astronomical writings of the ancient Greeks. Many of theancient Greek astronomical texts first became known in Europe because of Arabic astronomers. A lot of the maths used in astronomy was first worked out by Arabic astronomers.