《明史·志·卷八》
将黄道赤道的小弦，乘以黄道赤道的大股大股见弧矢割圆作为被除数。
置黄赤道小弦，以黄赤道大股乘之为实。
Multiply the short chord of the ecliptic and equator by the large segment of the ecliptic and equator, and the large arc is used as the constant to be divided into.