Su Song, who was Minister of Punishments and an expert in the calculation of calendars, led a team of skilled mathematicians and ingenious artisans to build the clock tower, which combined observational, demonstrational and time-keeping functions, and was the most advanced astronomical instrument of its day anywhere in the world.
集觀測、演示、報時等功能於一身，是當今世上最進步的天文儀器。