Guo Shoujing was a prominent Chinese astronomer, engineer, and mathematician during the Yuan Dynasty in the 13th century. He is best known for his work in astronomy, particularly for creating accurate astronomical instruments and for his contributions to the development of the Chinese calendar. His observations and calculations significantly improved the understanding of celestial movements. In addition to his astronomical achievements, Guo Shoujing also made notable advancements in hydraulic engineering. He designed and constructed irrigation systems that enhanced agricultural productivity in northern China. His work laid the foundation for future developments in both astronomy and engineering in China.