Giralda or “The Tower of Seville”, was the first observatory in Europe. This was 600 years before Galileo. It was built in 1190 C.E., in the Spanish (It was called ANDALUS under Muslim caliphate) town of Seville under the supervision of the celebrated Mathematician, Jabir Ibn Afiah.
It was meant for the observation of heavenly bodies. It was later turned into a bell tower by Christian conquerors, who, after the expulsion of the Moors, did not know how to use it.
The many references to astronomy in the Qur’an and hadith, and the injunctions to learn, inspired the early Muslim scholars to study the heavens. They integrated the earlier works of the Indus or Sindh Valley (Pakistan), Maggians and Greeks into a new production.
Muslims were inspired to investigate and study the Earth, the features of the land, methods of mapping and so on. Many new stars were discovered, as we see in their Arabic names – Algol, Deneb, Betelgeuse, Rigel, Aldebaran. Astronomical tables were compiled, among them the Toledan tables, which were used by Copernicus, Tycho Brahe and Kepler.
These works were used to determine the direction of Makkah from various locations, to improve navigation and surveying, and establishing correct time keeping and calenders. Using longitude and latitude, calculating the circumference of the Earth within a few hundred miles, the Muslim geographers greatly improved on Ptolemy’s famous ‘Almagest’, that it is not certain how much of the work actually belongs to the famous Greek, and how much was added to successive copies.
Muslim astronomers were the first to establish observatories, like the one built at Mugharah by Hulagu, the son of Genghis Khan, in Persia, and they invented instruments such as the quadrant and astrolabe, which led to advances not only in astronomy but in oceanic navigation, contributing to the European age of exploration. Other instruments used by muslim astronomers and navigators were the quadrant and the planisphere, a large, complicated device for plotting stars. Observatories were set up in desert locations where the best observations could be made.
Accurate measurement of time used very similar mathematical skills to those needed for navigation. Al-Biruni, a famous Muslim scholar of the 11th century, wrote a mathematical treatise on shadows that helped regulate sundials accurately.
What’s more, Al-Biruni, worked out that the earth is round and calculated its circumference. He also stated that the earth spins on its axis and rotates around the sun, nearly six hundred years before Galileo.