Chinese constellations

[2] The asterisms are divided into four groups, the Twenty-Eight Mansions (二十八宿, Èrshíbā Xiù) along the ecliptic, and the Three Enclosures of the northern sky.

The southern sky was added as a fifth group in the late Ming dynasty based on European star charts, comprising an additional 23 asterisms.

The Twenty-Eight Mansions form an ecliptic coordinate system used for those stars visible (from China) but not during the whole year, based on the movement of the Moon over a lunar month.

It contains collections of earlier Chinese astronomers (Shi Shen, Gan De and Wu Xian) as well as of Indian astronomy (which had reached China in the early centuries AD).

[citation needed] The southern sky was unknown to the ancient Chinese and is consequently not included in the traditional system.

The modern Chinese term for "constellation", referring to those as defined by the IAU system, is 星座 (xīng zuò).

From the viewpoint of the ancient Chinese, the Purple Forbidden Enclosure lies in the middle of the sky and is circled by all the other stars.

The Heavenly Market Enclosure covers the Greek constellations Serpens, Ophiuchus, Aquila and Corona Borealis, and parts of Hercules.

The names and determinative stars are:[9][10] The sky around the south celestial pole was unknown to ancient Chinese.

However, by the end of the Ming dynasty, Xu Guangqi introduced another 23 asterisms based on the knowledge of European star charts.

The asterisms are: Ancient Chinese astronomers designated names to the visible stars systematically, roughly more than one thousand years before Johann Bayer did it in a similar way.