Maragheh observatory

Maragheh observatory (Persian: رصدخانهٔ مراغه‎) is an astronomical observatory which was established in 1259 CE by Nasir al-Din al-Tusi, an Iranian scientist and astronomer. Located in the heights west of Maragheh, East Azarbaijan province, Iran, it was once considered one of the most prestigious observatories in the world. Considerable parts of the groundwork are preserved in the ruins. In a 340 to 135 m² citadel-like area stood a four-story circular stone building of 28 m diameter. The mural quadrant to observe the positions of the stars and planets was aligned with the meridian. This meridian served as Prime meridian for the tables in the Zij-i Ilkhani, as we nowadays apply the meridian which passes the Royal Greenwich...