Introduction to Zamaruddin: Zamaruddin, a Persian Hui, an astronomer of the Yuan Dynasty, his birth and death dates are unknown. He is famous for manufacturing astronomical instruments and compiling calendars and topographies. He also set up an observatory in Dadu (now Beijing) of the Yuan Dynasty and created 7 types of astronomical observation instruments. Zamaruddin devoted his life to the cause of astronomy and calendar, introduced the astronomical and calendar science of Persia and Arabia to China, and made important contributions to the development of Chinese astronomy, thus making China's astronomical and calendar science in the Yuan Dynasty leading the world.