of astronomy. Astronomers worked in the two Astronomical Bureaus, both of which underwent many changes throughout the years since their formation. The path into the occupation was hereditary; because of the rigidity and high level of intelligence needed for this occupation, children of astronomers were banned from pursuing other professions. Astronomical Bureaus When transitioning into the Ming dynasty, the two largest institutions of astronomy were the Traditional Chinese Astronomical Bureau (also named T’ai-shih-chien), which had been established in the third century BC, and the Muslim Astronomical Bureau (also named Hui-hui ssu-t’ien-chien), which had been previously established by the Mongols. Both sectors worked together, until the Muslim Bureau was absorbed in 1370 by the Traditional Chinese Bureau. When the merge occurred, the overall name of the new bureau became Ch’in-t’ien-chien. To accommodate the influx of new workers, the ranking system within the occupation also transitioned. There became one Director, supported by two Deputy Directors, followed by a Registrar with four seasonal Chiefs. Then came eight Chief Astronomers, five Chief Diviners, two Chiefs of the Clepsydras, and three Observers. Following that was two Calendar Officials, eight Observers of Sunrise, and six Professors of the Clepsydra. Responsibilities of the Bureau Some of the roles astronomers played in Ming China were to make calendars, report abnormalities to the emperor, and preside over ceremonies. As calendar makers and people who understand the heavens, the Bureau also decided what days were auspicious and good for different events such as military parades, marriage, construction, and more. The astronomers also used astronomy to predict invasions or dangerous moments within the empire. However, records indicate that the majority of work the Astronomical Bureaus did was simply recording the movements of the stars and planets. In regards to the specific jobs each position does, the Chief Officials of the Five Agencies would fix the calendar and the time of the seasons, along with the Calendar Officials and Astronomers. However, the Chief Astronomer observes the positions of the sun, moon, and planets to make notes regarding what might be an abnormality. The Chief Diviner specializes in analyzing the astronomical abnormalities. The Chief Clepsydra Officer looks after the CLepsydra, along with the Clepsydra professor, who then tell the Sunrise Announcer when sunrise and sunset would occur. Colleagues The Astronomical Bureaus worked closely with The Ministry of Rites. The bureau submitted monthly ordinances, planetary and celestial locations, and seasonal accounts within the calendar