thumb|Reproduction of the [[Suzhou star chart (13th century)]]
Traditional Chinese astronomy has a system of dividing the celestial sphere into asterisms or constellations, known as "officials" ().
The Chinese asterisms are generally smaller than the constellations of Hellenistic tradition.
The Song dynasty (13th-century) Suzhou planisphere shows a total of 283 asterisms, comprising a total of 1,565 individual stars.
The asterisms are divided into four groups, the Twenty-Eight Mansions () 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 Three Enclosures () include the Purple Forbidden Enclosure, which is centered on the north celestial pole and includes those stars which could be seen year-round, while the other two straddle the celestial equator.
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.
History
The Chinese system developed independently from the Greco-Roman system since at least the 5th century BC, although there may have been earlier mutual influence, suggested by parallels to ancient Babylonian astronomy.
The system of twenty-eight lunar mansions is very similar (although not identical) to the Indian Nakshatra system, and it is not currently known if there was mutual influence in the history of the Chinese and Indian systems.
The oldest extant Chinese star maps date to the Tang dynasty. Notable among them are the 8th-century Treatise on Astrology of the Kaiyuan Era and Dunhuang Star Chart.
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).
Gan De was a Warring States era (5th century BC) astronomer who according to the testimony of the Dunhuang Star Chart
enumerated 810 stars in 138 asterisms. The Dunhuang Star Chart itself has 1,585 stars grouped into 257 asterisms.
The number of asterisms, or of stars grouped into asterisms, never became fixed, but remained in the same order of magnitude (for the purpose of comparison, the star catalogue compiled by Ptolemy in the 2nd century had 1,022 stars in 48 constellations).
The 13th-century Suzhou star chart has 1,565 stars in 283 asterisms, the 14th-century Korean Cheonsang Yeolcha Bunyajido has 1,467 stars in 264 asterisms, and the celestial globe made by Flemish Jesuit Ferdinand Verbiest for the Kangxi Emperor in 1673 has 1,876 stars in 282 asterisms.
The southern sky was unknown to the ancient Chinese and is consequently not included in the traditional system. With European contact in the 16th century, Xu Guangqi, an astronomer of the late Ming dynasty, introduced another 23 asterisms based on European star charts. The "Southern Asterisms" () are now also treated as part of the traditional Chinese system.
Terminology
The Chinese word for "star, heavenly body" is .
The character originally had a more complicated form: , a phono-semantic character () whose semantic portion, , originally depicting three twinkling stars (three instances of the "sun" radical ).
The modern Chinese term for "constellation", referring to those as defined by the IAU system, is (). The older term () is used only in describing constellations of the traditional system. The character 's main meaning is "public official" (hence the English translation "officials" for the Chinese asterisms), it historically could also meant "official's residence".
The generic term for "asterism" is (, lit. "group of stars").
Three Enclosures
The Three Enclosures are the Purple Forbidden enclosure (), the Supreme Palace enclosure () and the Heavenly Market enclosure ().
The Purple Forbidden Enclosure occupies the northernmost area of the night sky. 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.
It covers the Greek constellations Ursa Minor, Draco, Camelopardalis, Cepheus, Cassiopeia, Auriga, Boötes,
and parts of Ursa Major, Canes Venatici, Leo Minor and Hercules.
The Supreme Palace Enclosure covers the Greek constellations Virgo, Coma Berenices and Leo,
and parts of Canes Venatici, Ursa Major and Leo Minor.
The Heavenly Market Enclosure covers the Greek constellations Serpens, Ophiuchus, Aquila and Corona Borealis,
and parts of Hercules.
The Three Enclosures are each enclosed by two "wall" asterisms, designated "low wall, fence; enclosure" (not to be confused with the lunar mansion ""Wall" ):
- Purple Forbidden Left Wall (Cassiopeia / Cepheus / Draco)
- Purple Forbidden Right Wall (Draco / Ursa Major / Camelopardalis)
- Supreme Palace Left Wall (Virgo / Coma Berenices)
- Supreme Palace Right Wall (Leo / Virgo)
- Heavenly Market Left Wall (Hercules / Serpens / Ophiuchus / Aquila)
- Heavenly Market Right Wall (Serpens / Ophiuchus / Hercules)
The Twenty-Eight Mansions
400px|right|thumb|A modern star chart showing the traditional Chinese asterisms, with the 24 [[solar terms indicated on the border of each hemisphere.]]
The Twenty-Eight Mansions are grouped into Four Symbols, each associated with a compass direction and containing seven mansions. The names and determinative stars are:
{| class="wikitable"
|-
!rowspan="2" align="center"|Four Symbols<br />() !! colspan="4" align="center" | Mansion ()
|-
! Number !! Name (pinyin) !! Translation !! Determinative star
|-
|rowspan="7" |Azure Dragon<br />of the East <br />()<br />Spring
| 1 || () || Horn || α Vir
|-
| 2 || () || Neck || κ Vir
|-
| 3 || () || Root || α Lib
|-
| 4 || () || Room || π Sco
|-
| 5 || () || Heart || α Sco
|-
| 6 || () || Tail || μ Sco
|-
| 7 || () || Winnowing Basket || γ Sgr
|-
|rowspan="7" |Black Tortoise<br />of the North <br />()<br />Winter
| 8 || () || (Southern) Dipper || φ Sgr
|-
| 9 || () || Ox || β Cap
|-
| 10 || () || Girl || ε Aqr
|-
| 11 || () || Emptiness || β Aqr
|-
| 12 || () || Roof || α Aqr
|-
| 13 || () || Encampment || α Peg
|-
| 14 || () || Wall || γ Peg
|-
|rowspan="7" |White Tiger<br />of the West <br />()<br />Fall
| 15 || () || Legs || η And
|-
| 16 || () || Bond || β Ari
|-
| 17 || () || Stomach || 35 Ari
|-
| 18 || () || Hairy Head || 17 Tau
|-
| 19 || () || Net || ε Tau
|-
| 20 || () || Turtle Beak || λ Ori
|-
| 21 || () || Three Stars || ζ Ori
|-
|rowspan="7" |Vermilion Bird<br />of the South <br />()<br />Summer
| 22 || () || Well || μ Gem
|-
| 23 || () || Ghost || θ Cnc
|-
| 24 || () || Willow || δ Hya
|-
| 25 || () || Star || α Hya
|-
| 26 || () || Extended Net || υ¹ Hya
|-
| 27 || () || Wings || α Crt
|-
| 28 || () || Chariot || γ Crv
|}
The Southern Asterisms
The sky around the south celestial pole was unknown to ancient Chinese. Therefore, it was not included in the Three Enclosures and Twenty-Eight Mansions system. However, by the end of the Ming dynasty, Xu Guangqi introduced another 23 asterisms based on the knowledge of European star charts. These asterisms were since incorporated into the traditional Chinese star maps.
The asterisms are:
{| class = "wikitable"
|-
! English name || Chinese name || Number of stars||Hellenistic Constellation
|-
| Sea and Mountain || () || 4 || Carina/Centaurus/Musca/Vela
|-
| Cross || () || 4 || Crux
|-
| Horse's Tail || () || 3 || Centaurus
|-
| Horse's Abdomen || () || 3 || Centaurus
|-
| Bee || () || 4 || Musca
|-
| Triangle || () || 3 || Triangulum Australe
|-
| Exotic Bird || () || 9 || Apus / Octans
|-
| Peacock || () || 11 || Pavo
|-
| Persia || () || 11 || Indus / Telescopium
|-
| Snake's Tail || () || 4 || Octans / Hydrus
|-
| Snake's Abdomen || () || 4 || Hydrus
|-
| Snake's Head || (S) || 2 || Hydrus / Reticulum
|-
| Bird's Beak || () || 7 || Tucana
|-
| Crane || () || 12 || Grus / Tucana
|-
| Firebird || () || 10 || Phoenix / Sculptor
|-
| Crooked Running Water || () || 3 || Eridanus / Phoenix
|-
| White Patches Nearby || () || 2 || Hydrus
|-
| White Patches Attached