Astronomy in medieval Islam was a thriving field that enjoyed a lot of state support in some cases, and there were quite a few observatories built. They did not have telescopes, that being a 17th-century European invention, and so concerned themselves more with practical elements of astronomy- observing the movements of the sun, stars, moon, and planets, and using their observations for such purposes as navigation and timekeeping. It is important to note that these two fields have religious significance in Islam, being important for determining the direction to Mecca (the qibla), the time for prayers, and the date of religious events such as Ramadan.

Without telescopes, there wasn't much advancement in astronomy as a pure science. They operated under a geocentric theory, as did Europe until later developments, building on the Ptolemaic model and refining it for more accurate predictions of celestial events. Planets were understood to operate differently from stars, both in terms of their motion and that they could (as observed on a few occasions) pass between the Earth and the Sun, but what exactly they were was unknown. Astronomers in observatories would have worked with instruments like astrolabes and armillary spheres, compiling tables of observed and predicted celestial movements for use by travelers, traders, sailors, muezzins, architects, and anyone else with an interest in knowing their location and orientation, as well as the time and date. Within the limits of their tools and knowledge, this was quite a refined and exact science with great utility.