Shang Dynasty (about 1600-1100 BC)
The Shang Dynasty had been largely in the realm of myth, but around the turn of the century (1900), `oracle bones' with a written record were found in the fields of Chinese farmers.
During the Shang Dynasty, the Chinese had in place interlocking cycles of 10 days and 12 days; together, these made a cycle of 60 days.
Han Dynasty (about 200 BC - 200 AD)
The Han dynasty was preceded by the reign of Emperor Qin, who unified a large part of China. China then covered a large area, including about 20 degrees in latitude. Records were brought to the capital from throughout China, so that differences in astronomical observations at different places could play a role.
Before the Han Dynasty, the Chinese developed a method of mapping out the celestial sphere using equatorial coordinates.
During the Han dynasty, there were the beginnings of cosmological speculation; debates took place between 3 competing schools of thought.