ABSTRACT
Liu Hong is the first Chinese astronomer who has left us a complete theory of the moon taking into account lunar motion in latitude, as well as the moon’s first inequality of motion in longitude. This is set out in his Qian xiang li 乾象曆 ‘Uranic Manifestation [astronomical] system’, which appears to have come down to us in its entirety. There is no reason to doubt that this is not only the earliest surviving full lunar theory from China, but also the earliest actually created there (Cullen, Christopher 2002). The quite detailed discussions of related questions in ancient Chinese sources do not refer to any work of this level of detail and precision pre-dating Liu Hong, although in the late first century ce Jia Kui 賈逵 did discuss variations in the speed of the moon, and gave a good estimate of the monthly displacement of the position of maximum lunar speed (see section 5.3.9).
