Astrologers predict that your capital will rebel against you? Just build a new capital next door and force everyone to move there. Problem solved!

I did some research. It appears that the Great Comet of 1264 was indeed recorded by the Chinese in Records of the Grand Historian, the first comprehensive history of China. Additionally, there is evidence that might suggest important decisions such as moving the capital may have been made due to comet sightings. Emperor Ruizong of Tang abdicated the throne in 712 AD after a comet appeared in the sky. > Ancient Chinese astrology set great store by celestial omens and comets were an important omen, always disastrous. Under the theory of Wu Xing, comets were thought to signify an imbalance of yin and yang. Chinese emperors employed observers specifically to watch for them. >Comets were thought to have military significance. For instance, the breakup of a comet on 25 January 35 AD was interpreted as portending the destruction of Gongsun Shu by Wu Han, general to emperor Guangwu. In fact, the Chinese still use language revolving around comets being a bad omen. >In a Chinese family, daughters-in-law are considered outsiders and are blamed for creating problems in the family, especially with their mother-in-law. Because of this, they are often referred to as a "comet." E.g. "Oh my God, my son married a comet!" >A wife who is a comet has been known to bring down the fortune of not only her husband, but the wealth and well-being of the entire family. >However, the usage of 'comet' is not only limited to daughters-in-law. It is also used on other familial outsiders such as maids, employees, and others. So I think it must be the case that the sighting of that particular comet was the reason behind the capital being moved.