edictions and hoping the results would match the observations. In 237, the <i>J&#464;ngch&#363;</i> almanac (景初曆) was constructed, in which the anomalistic month was not tied to the superior epoch. As a result, the adopted anomalistic month was much closer to the measurement value than the previous almanac. In 443, astronomer H&#233; Ch&#233;ngti&#257;n (何承天) created the <i>Yu&#225;nji&#257;</i> almanac (元嘉曆), in which the synodic periods of the five planets were based on observations and 