This module (blurb here) is a stand-alone adventure that can be easily ported to The Celestial Empire. It must be set under the Míng or under the Qīng. If set under the Míng, then it must be set at the beginning of the Míng so that the Stargazer was active under the Yuán. If set under the Qīng, then it must be set at the end of the 18th century so that the Stargazer was active at the end of the 17th century.
The rationale behind these time frames is the major astronomic advances that happened under the Yuán because of the presence of Arab and Persian astronomers. Likewise, there were major astronomic advances at the end of the 17th century thanks to the Jesuit missionaries present at the court of the Kāngxī Emperor.
The rest of this post is hidden because of major spoilers that it contains.
As suggested on p5 of the module, the tower should be placed away from any settlements, possibly in the mountains — which is by the way the most logical place to build an observatory.
Page 9: The dead thief is actually a dead bandit, famous in the Rivers and Lakes.
Page 10, Sitting Room: It's obviously rice wine, not grape wine.
Page 11, Sitting Room: It is the statue of a vixen lady embracing a mandarin.
Page 13, Head Servant's Quarters: His name was Tái Ānruì
Page 14, Wizard's Quarters: His name is Shěn Yùruì
Page 15: The reward is 10 gold taels. More generally, use the 10gp=1 gold tael equivalence throughout the module.
Page 17: Shěn Yùruì is a very powerful (POW 18) Daoist magician. Just make sure he has plenty of offensive spells.
Page 21, Library: The books in the library are written in Arabic if the adventure is set at the beginning of the Míng; they are written in Latin if it is set at the end of the 18th century.
Page 22, The Ghost: obviously it will be a game of go (wéiqí)
Page 23, Eldritch Library: The books in the library are written in Classical Chinese, with many unusual Daoist versions of the characters (-25% to read, unless the reader is himself a member of a Daoist sect). The scrolls will contain Daoist spells, possibly gǔ sorcery spells.
Pages 24-25, Workshop and Telescope: the book on the podium is written in Arabic/Latin (depending on the era).
Page 28, Trap Room: the POT of the spider poison is 13.