Ancient China Astronomy

Astronomy in China developed along with writing and divination during the Shang Dynasty. The first inscriptions of star names were found on oracle bones. The concept of the twenty-eight mansions seems to have appeared during the rule of Wu Ding (1339–1281 BCE).

During the Warring states and especially the Han period, Chinese astronomers started keeping a detailed record of their observations.

Chinese astronomy was essentially different from traditional Wester astronomy because it was based on different principles.
Dunhuang star map

It was equatorial, which means that it was focused on close examination of circumpolar stars, rather than on heliacal risings and settings of zodiac constellations.

The ancient Chinese were among the most determined and accurate observers of astronomic phenomena in the word. In ancient times, only the Islamic astronomers could compare with them.

The Chinese were thorough in keeping astronomical records. Thanks to that, now we know that Chinese astronomy hasn’t changed much from 1800 BCE onwards – but it did change a lot during earlier epochs.

Astronomy was a very important discipline in ancient China. The knowledge of astronomical phenomena and keeping accurate records of time was the domain of emperors.

For those reasons, emperors employed astronomers to work for them directly.Astronomy and astrology were entirely separated in ancient China.
Wide View of the Crab Nebula

The astronomers charted lunar eclipses and other regular events, while the astrologers tried to find omens in the sky.

The work of ancient Chinese astronomers

  • The key responsibility job of the Chinese astronomers was to keep records on time, which also meant that they had to announce the first day of every month and to know in advance when the next lunar eclipse would take place. They had an enormous responsibility. If their predictions were wrong, the astronomers would often be beheaded.
  • During the rule of Emperor Huang Ti, Chinese astronomers divided the sky into 12 branches and 10 stems. These were arranged to give a 60-year cycle. Emperor Huang Ti was said to have constructed an impressive observatory and planetarium to assure that observations were accurate.
  • The Chinese thoroughly recorded a variety of astronomical phenomena, including comets, solar flares, novas, and sunspots. They did that ages before other cultures started making similar observations. Actually, the Chinese made a great effort in order to catalog every star in the sky.
  • The most famous ancient Chinese astronomers were Shi-Shen, who lived in the 4thcentury BCE, and Kan-Te. Shi-Shen wasn’t much interested in the planets, but his interest in the stars and the prenomena such as sunspots was extraordinary. He categorized over 800 stars in 122 constellations.
  • The Chinese probably used an armillary sphere to make precise measurements of position in the sky and give each star a coordinate.
  • One of the most significant star maps in the ancient world was the Dunhuang Star Map, which was created during the Tang Dynasty.
  • The most accurate measuring instruments were constructed between the 3rdand the 6th Astronomer Zu Chongzhi used the instruments that he developed and stated that the year was 365.24281481 days long. His measurements differ from present-day measurements in less than a minute. This astronomer also designed the surprisingly precise lunisolar calendar called the Daming calendar.
  • Another famous astronomer from the Tang dynasty was Yi Xing – the first astronomer who ever tried to determine the length of the meridian line. He proposed that this line was 123.7km, which is surprisingly close to the actual value – today we know it is 111km.

While the Greek, Indian, and Islamic astronomers developed more theories, the Chinese beat them in accuracy.

Their main concern was to be as precise as possible and to refine their observations. As a result, they were able to chart and predict comets and meteor showers, novae, and other rare phenomena
A method of making observation instruments at the times of Qing Dynasty


How was astronomy related to divination and writing in ancient China?

The first inscriptions of star names were found on oracle bones.

Why Chinese astronomers are so important when they didn’t develop as many theories as their European colleagues did?

The Chinese were accountable for the accuracy of data, and precision was their main concern. Because of that, their observations were much more trustworthy than those of their European contemporaries.

What was the consequence of inaccurate astronomical prediction?

The astronomer would be sentenced to death.

What was the name of Chinese astronomer from the Tang dynasty period who realized that year was 365.24281481 days long?

His name was Zu Chongzhi.