Astronomy and Chief Astronomer authority in Islamic civilization

In our society, it is thought that Muslims have taken all developments from other nations. Howeverwhen we look at the historical process of astronomy, we conclude that Islamıc scientists made lots of firsts in this field. For this reason, we think that the history of Islamic science needs more research. The time is very important in the religion of Islam. This situation has paved the way for the development of sky observations and their spread in the society. In the Islamic civilization, astronomical activities started as simple sky observations. They used for these observations for determination of some prayers time such as prayer, fasting, zakat and pilgrimage. When people learned that celestial bodies have an effects on humans, they started to take into account in their lives. In the periods of Umayyads and Abbasid, translations were made from other civilisations. With the help of these translations, accumulation of knowledge in astronomy increased. In this period, Islamic scientists increased their observations in order to check what they learned. Many emperors had a man who determine the time for call to prayer and astronomers. And the emperors consulted them in state affairs. Astronomy activities were widespread and these activities were in the state body. So observatories have begun to be established.Many observation instruments were invented and developed. With the help of these observation instruments, astronomical activities developed. Observatories' activities contributed Islamic Science. And these activities' contributions have been used as a basic knowledge in the history of science. We see the chief of astronomers as an authority in Ottoman Empire. This authority made many contrubitions to the development of astronomical activities. Today, observation activities continue in the time calculation unit of The Religious Affairs Administration. Keywords: Islamic Civilization, Astronomy, History of Science, Sky Observations, Time Determination