《明史·志·卷一》
当时正开设官署修撰历法，没有时间分别到各地测量，度数实际上有很多不确切的地方，存留在此，以留作参考订正。
其时开局修历，未暇分测，度数实多未确，存之以备考订云。
At the time, there was an official office responsible for drafting the calendar, however, there was no time to take measurements in various places, so there are many inaccuracies in the degrees. These are recorded here, to provide a point of reference for corrections.