Although the calendar used by Great Qi improved every year, it was actually extrapolated according to the Tongtian Calendar left behind by the previous dynasty. The Tongtian Calendar was in turn derived from the Great Yan Calendar of the Tang Dynasty.
In order to compile an astronomical calendar, not only did one have to be proficient in astronomy and geography, but they also had to know farming and numerology. It was not something ordinary people could do. Once it was done, the creator would definitely leave his name in history.
Of course, Mu Yangling did not think that her younger brother would do such a thing for the sake of leaving his name in history. However, the key was that she had never realized that he was especially interested in such things in the past. Well-read in all four books and five scriptures, he had also discussed history books with her. Why did he take a sudden interest in the astronomical calendar now?