24;ngyu&#225;n</i> may be translated as <i>superior epoch</i> and I will use <i>superior epoch</i> and <i>sh&#224;ngyu&#225;n</i> interchangeably hereafter.</p><p>Chinese astronomers discovered the non-uniform motion of the Moon in the first century. We now know that it is caused by the orbital eccentricity of the Moon. The cycle of the non-uniform motion is called the <i>anomalistic month</i>, which is the average time between two successive perigee passages of the Moon. It was also known that the average 