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{{DISPLAYTITLE: Tianhun (天溷)}} 

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{{Infobox constellation|name=Tianhun (天溷)|native=天溷|translation=Celestial Pigsty|pronounce=Tiān 
Hùn|IPA=/tʰjɛn˥.xwən˥˩/|culture=Chinese|RA=8.812 to 19.45083333|dec=-7.924 to 5.65|areatotal=0|numbermainstars=7|numberbfstars=6|numberstarsplanets=|numberbrightstars=0|numbernearbystars=|brighteststarname=20 Cet|starmagnitude=4.76|neareststarname=|stardistance=|numbermessierobjects=|meteorshowers=|bordering=Cet, Psc|notes=|cat=constellation}}

Tianhun (天溷) is a Chinese asterism belonging to the [[Kui]] (Legs) lunar mansion. Among the Three Schools, it is classified as an external constellation of the Gan School (甘氏). The asterism consists of seven stars located to the south of [[Waiping]] (Outer Fence), within the modern constellation [[Cetus]] and [[Pisces]].

== Concordance, Etymology, History ==

The name Tianhun combines ''tiān'' (天, celestial) with ''hùn'' (溷), whose original character is 圂 (hùn). The two characters 溷 and 圂 were interchangeable in ancient texts due to their identical pronunciation, and 溷 eventually became the more commonly used form in transmitted literature. The ''Shuowen Jiezi'' (説文解字) defines 圂 as "a latrine" (圂，廁也) and explains its structure: "It is composed of 囗 (enclosure) with 豕 (pig) inside. A pig within an enclosure is called hùn" (从囗，象豕在囗中也。豕在囗中，故謂之圂). The character's very form thus depicts a pig in a pen — a pigsty — which in ancient Chinese rural architecture was typically combined with a latrine. This dual function of pigsty and latrine is the core meaning of the asterism.

The ''Gan Shi Zan'' (甘氏讚, ''Gan's Eulogy'') describes Tianhun as "the pit for excrement and the mound of dung" (杼廁糞丘), and the ''Kaiyuan Zhanjing'' (開元占經) states simply: "Tianhun is the latrine" (天溷，廁也). The asterism's origin is directly tied to the symbolism of the [[Kui]] mansion, which is traditionally associated with the pig ([[Shimu|Tianshi]], 天豕). Tianhun represents the celestial pigsty and latrine — the functional counterpart to the pig's celestial presence. Its position south of [[Waiping]] (Outer Fence) is deliberate: the Gan Shi (甘氏) states that the Outer Fence "serves to screen Tianhun" (外屏，所以障天溷也). The ''Shi Ji·Zheng Yi'' (史記正義) explains: "The [[Waiping|Outer Fence]] is south of [[Kui]], shielding the Celestial Pigsty (Tianhun), so that its foul odours are not seen” (外屏在奎南，障天溷，令其臭穢不見也).

The ''Sui Shu·Tianwen Zhi'' (隋書·天文志, ''Book of Sui, Treatise on Astronomy'') records:
<blockquote>Seven stars south of Kui are called Waiping; seven stars south of Waiping are called Tianhun, the latrine. The screen serves to shield it. (奎南七星曰外屏，外屏南七星曰天溷，廁也。屏所以障之也。)</blockquote>
The ''Song Shi·Tianwen Zhi'' (宋史·天文志) similarly states: <blockquote>Waiping, seven stars, is south of Kui, governing the screening of foul odours. (外屏七星，在奎南，主障蔽臭穢。)</blockquote>
It further describes Tianhun as "the place for the celestial latrine and pig-rearing" (主天廁養豢之所), and notes that when it is dim, the people are uneasy.

=== Identification of stars ===

{| class="wikitable"
!Star Names or Orders(Qing)
!Han Dynasty (SUN X. & J. Kistemaker<ref>Sun Xiaochun. & Kistemaker J. ''The Chinese sky during the Han''. Leiden: Brill. 1997, Pp241-6.</ref>)
!3rd to 6th Century (Boshun Yang<ref name=":12">B.-S. Yang杨伯顺, ''Zhongguo Chuantong Hengxing Guance Jingdu ji Xingguan Yanbian Yanjiu'' 中国传统恒星观测精度及星官演变研究 (A Research on the Accuracy of Chinese Traditional Star Observation and the Evolution of Constellations), PhD thesis, (Hefei: University of Science and Technology of China, 2023), Pp297-304.</ref>)
!Song Dynasty (Pan Nai<ref name=":02">Pan Nai潘鼐. ''Zhongguo Hengxing Guance shi''中国恒星观测史[M]. Shanghai: Xuelin Pree. 1989, Pp220-226.</ref>, 1052 CE)
!Song Dynasty (Boshun Yang<ref name=":12" />, 1052 CE)
!Qing Dynaty (Yi Shitong<ref>Yi Shitong伊世同. ''Zhongxi Duizhao Hengxing Tubiao''中西对照恒星图表1950. Beijing: Science Press.1981.</ref>, 18th Century)
|-
|1st
| valign="center" |20 Cet
| valign="center" |20 Cet
| valign="center" |20 Cet (determinative）
| valign="center" |20 Cet (determinative）
| valign="center" |21 Cet
|-
|2nd
| valign="center" |25 Cet
| valign="center" |25 Cet
| valign="center" |25 Cet
| valign="center" |25 Cet
| valign="center" |φ3 Cet
|-
|3rd
| valign="center" |39 Cet
| valign="center" |37 Cet (determinative)
| valign="center" |39 Cet
| valign="center" |39 Cet
| valign="center" |18 Cet
|-
|4th
| valign="center" |42 Cet
| valign="center" |39 Cet
| valign="center" |42 Cet
| valign="center" |42 Cet
| valign="center" |φ1 Cet
|-
|5th
| valign="center" |89 Psc
| valign="center" |89 Psc
| valign="center" |89 Psc
| valign="center" |89 Psc
| valign="center" |(deleted)
|-
|6th
| valign="center" |80 Psc
| valign="center" |80 Psc
| valign="center" |80 Psc
| valign="center" |80 Psc
| valign="center" |(deleted)
|-
|7th
| valign="center" |73 Psc
| valign="center" |HIP 3765
| valign="center" |HIP 3992
| valign="center" |HIP 3992
| valign="center" |(deleted)
|}

=== Maps (Gallery) ===

{| class="wikitable"
|+
!historical map
!modern identification
!same in Stellarium
|-
|[[File:Zuogeng and Yougeng on Cheonsang Yeolcha Bunyajido.png|alt=Zuogeng and Yougeng on Cheonsang Yeolcha Bunyajido|thumb|Zuogeng and Yougeng in ''Cheonsang Yeolcha Bunyajido'']]
| rowspan="3" |[[File:Zuogeng and Yougeng before Tang Dynasty reconstructed by Boshun Yang (2023).png|alt=Zuogeng and Yougeng before Tang Dynasty reconstructed by Boshun Yang (2023)|thumb|Zuogeng and Yougeng before Tang Dynasty reconstructed by Boshun Yang (2023)]]
| rowspan="3" |[[File:Zuogeng and Yougeng before Song dynasty in Stellarium.png|alt=Zuogeng and Yougeng before Song dynasty in Stellarium|thumb|Zuogeng and Yougeng before Tang dynasty in Stellarium reconstructed by Boshun Yang]]
|-
|[[File:Zuogeng and Yougeng in Dunhuang Star Map.png|alt=Zuogeng and Yougeng in Dunhuang Star Map|thumb|Zuogeng and Yougeng in Dunhuang Star Map]]
|-
|[[File:Zuogeng and Yougeng in Geziyuejintu.png|alt=Zuogeng and Yougeng in Geziyuejintu|thumb|Zuogeng and Yougeng in ''Geziyuejintu'']]
|-
|[[File:TIancang in Xinyixiangfayao Star Map.png|alt=TIancang in Xinyixiangfayao Star Map|thumb|TIancang in ''Xinyixiangfayao'' Star Map]]
| rowspan="2" |[[File:Zuogeng and Yougeng in Song Dynasty (Huangyou period) reconstructed by Pan Nai (2009).png|alt=Zuogeng and Yougeng in Song Dynasty (Huangyou period) reconstructed by Pan Nai (2009)|thumb|Zuogeng and Yougeng in Song Dynasty (Huangyou period) reconstructed by Pan Nai (2009)]][[File:Zuogeng and Yougeng in Song Dynasty (Huangyou period) reconstructed by Boshun Yang (2023).png|alt=Zuogeng and Yougeng in Song Dynasty (Huangyou period) reconstructed by Boshun Yang (2023)|thumb|Zuogeng and Yougeng in Song Dynasty (Huangyou period) reconstructed by Boshun Yang (2023)]]
| rowspan="2" |[[File:Zuogeng and Yougeng in Northern Song dynasty (11th century) in Stellarium.png|alt=Zuogeng and Yougeng in Northern Song dynasty (11th century) in Stellarium|thumb|Zuogeng and Yougeng in Northern Song dynasty (11th century) in Stellarium]]
|-
|[[File:Zuogeng and Yougeng in Suzhou Star Map.png|alt=Zuogeng and Yougeng in Suzhou Star Map|thumb|Zuogeng and Yougeng in Suzhou Star Map]]
|-
|[[File:Zuogeng and Yougeng in Yixiang kaocheng star map of 18th century.png|alt=Zuogeng and Yougeng in Yixiang kaocheng star map of 18th century|thumb|Zuogeng and Yougeng in ''Yixiang kaocheng'' star map of 18th century]]
|[[File:Tiancang in Qing dynasty reconstructed by Yi Shitong based on Yixiang Kaocheng Star Catalogue (18th century).png|alt=Tiancang in Qing dynasty reconstructed by Yi Shitong based on Yixiang Kaocheng Star Catalogue (18th century)|thumb|Tiancang in Qing dynasty reconstructed by Yi Shitong based on ''Yixiang Kaocheng'' Star Catalogue (18th century)]]
|[[File:Zuogeng and Yougeng in Qing dynasty (18th century) in Stellarium.png|alt=Zuogeng and Yougeng in Qing dynasty (18th century) in Stellarium|thumb|Zuogeng and Yougeng in Qing dynasty (18th century) in Stellarium]]
|}

== IAU Working Group on Star Names ==
In 2026, the name of the historical constellation "Tianhun" was suggested to be used for 20 Ceti in this constellation, as it is the determinative star in the Huangyou star catalogue and the brightest star of the asterism.

Decision: ... 

==References ==
[[References (Chinese)]]
[[Category:Asterism ]][[Category:Constellation ]]
[[Category:Eurasia]][[Category:Asian]][[Category:East Asian]]
[[Category:Chinese ]]
[[Category:Cet]]
[[Category:Psc]]