Radkan Tower

From the photographer: “The tower of Radkan was built in 660 Hejri = 640 Khorsidi = 1261 A.D. by Khajeh Nasir Tusi’s group. The Maragheh observatory was built & finished in 660 hejri, at the same time. The Tower of Radkan finds the first day of all seasons (equinoxes and solstices days) and leap years. It also helps to find the midday of all sunny days. When we watch the stars on top of Radkan Tower we can find their latitude and azimuth, like a telescope.”