Although the Ming had adopted Guo Shoujing's Shoushi calendar of 1281, which was just as accurate as the Gregorian Calendar, the Ming Directorate of Astronomy failed to periodically readjust it; this was perhaps due to their lack of expertise since their offices had become hereditary in the Ming and the Statutes of the Ming prohibited private involvement in astronomy.
Deși Ming a adoptat calendarul Shoushi din 1281, al lui Guo Shoujing, care a fost la fel de precis precum calendarul gregorian, Direcoratul Ming de Astronomie nu a reușit să îl re-adapteze periodic, acest lucru a fost, probabil, din cauza unei lipsei de expertize, conducerea biroului devenind ereditară în dinastia Ming și statutul dinastiei interzicea implicarea privată în astronomie.