《晋书·志·第七章》
如果月处在阳历，加上所在黄道历去极度，如果月处在阴历，则减之，所得为月去极度。
其阳历以加日所在黄道历去极度，阴历以减之，则月去极度。
If the moon is in the solar calendar, add the ecliptic calendar degree to the extreme, if the moon is in the lunar calendar, subtract it, and the result is the Moon's degree from the extreme.