China

Though “oracle bones” exist from the late 2nd millennium BCE that mention observations of lunar and solar eclipses as well as the appearance of a new star (nova), astronomical reports begin to be fairly numerous only from about 200 BCE. In China astronomy had an imperial function. The emperor was considered the Son of Heaven. Thus, the regulation of the calendar, as well as the success or failure of his astronomers to predict an eclipse, reflected either well or badly on him. Many different astronomical summaries were written in conjunction with the ascent of a new emperor. Usually these emphasized the lunisolar calendar, but later they also included tables for predicting the motions of the planets, as well as eclipses. Chinese predictive astronomy used repeating arithmetical cycles and was thus more like Babylonian astronomy than like Greek astronomy. Perhaps because the Chinese were less tied up with cosmological theories and “laws” of nature than the Greeks and their medieval European successors were, the Chinese astronomers were much more interested in singular events, such as comets, novae, meteor showers, solar eclipses, and sunspots (which the Chinese discovered before the Europeans), and they kept detailed records of them.

Renaissance

European astronomy regained the level of the ancient Greeks only with the publication in 1496 of Epytoma in Almagestum Ptolemaei (“Epitome of Ptolemy’s Almagest”) begun by mathematician and astronomer Georg von Peuerbach and completed by his student Regiomontanus (the Latin name of Johannes Müller von Königsberg). Regiomontanus’s chapter-by-chapter commentary helped the next couple of generations learn their Ptolemy. He sometimes criticized Ptolemy—for example, pointing out that the twofold variation in the distance of the Moon implied by Ptolemy’s lunar theory greatly exceeded the variation in distance implied by the Moon’s variation in apparent size. Although this variation had been known in Arabic astronomy, this was its first mention in the Latin West.