 mass ratio of the Sun and Earth. In this sense, the astronomical constants determined by matching the superior epoch, such as the anomalistic month, sidereal year and so on, were derived constants. This seems weird because one would think that these should be constants determined from observations. However, in the ancient <i>sh&#224;ngyu&#225;n</i> system, the measurement values were taken for reference only, the actual values used in the almanacs were determined by adjusting the measurement values to matc