In the middle of the Eastern Han Dynasty, Zhang Heng，an outstanding astronomer, made bold innovations to the armillary sphere，and de-signed and made the first water-driven armillary sphere in the world to measure the position of celestial bodies，which was carved with known important astronomical phenomena. People could observe the movement of the sun，the moon and the stars.
汉中期，杰出的天文学家张衡对浑仪作了大胆创新，设计并制作了漏水转浑天仪。张衡还制造出了世界上第一架测量天体位置的水运浑天仪，凡是已知的重要天文现象，都刻在这架仪器上。人们可以通过浑天仪观测到日月星辰运行的情况。
