Chugao (蒭藁)

Authors: Lyu Haocheng, Susanne M Hoffmann

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Chugao in Stellarium

Chugao (蒭藁)

Asterism Info
Native	蒭藁
Romanisation	Chú Gǎo
IPA	/t͡ʂʰu˧˥.kɑʊ˨˩˦/
Translation	Hay
Position (2000)
Right ascension	35.50895833 to 40.39520833
Declination	-15.24663889 to -9.454111111
Area	0 sq. deg.
Stars
Bright stars	6
Bayer/Flamsteed stars	3
Stars brighter than 3.00m	0
Brightest star	σ Cet (4.75m)
Taxonomy
category of asterism	constellation
IAU- constellations	Cet

Chú Gǎo (蒭藁, Hay) is a Chinese asterism belonging to the Mǎo (昴, Hairy Head) lunar mansion. Among the Three Schools, it is classified as an external constellation of the Gan School (甘氏). The asterism consists of six stars located to the west of Tiānyuàn (天苑, Celestial Meadow), within the modern constellation Cetus.

Concordance, Etymology, History

The name Chugao is composed of two characters denoting animal feed. Chú (蒭/芻) refers to fresh-cut green grass or hay; gǎo (藁) denotes dried stalks of grain crops, such as millet or rice straw. Together, the term signifies fodder and straw — the feed used for cattle, horses, and other livestock. The Gan Shi Zan (甘氏讚, Gan's Eulogy) explains: "Green grass is called chú; grain stalks are called gǎo." (生草曰蒭，禾稗曰藁)

The asterism's origin is closely tied to both the granary symbolism of the Wèi (胃) mansion and the pastoral symbolism of the Lóu (婁) mansion. The Gan School locates Chugao six stars west of Tiānyuàn (天苑), the celestial meadow or pasture. Its primary function, as recorded in the Jin Shu·Tianwen Zhi (晉書·天文志, Book of Jin, Treatise on Astronomy), is to provide fodder for cattle and horses (以供牛馬之食也). Xi Meng (郗萌) records an alternative name: Tiānjī (天積, Celestial Accumulation), explaining that it is the treasury of the Son of Heaven. The Huangdi Zhan (黄帝占) states that when the stars within Tiānjī are numerous, the hundred storehouses are full; when absent, the stores are dispersed.

The Kaiyuan Zhanjing (開元占經) also preserves the interpretation of the Yu Gong (禹貢) that Chugao represents the "service domain" (甸服) — the innermost ring of territory around the royal capital, whose inhabitants were obligated to deliver fodder and grain to the court: "The service domain delivers the bundled and the cut; the stalks are gathered and the ears are reaped, to supply the food of cattle and horses." (甸服入之，以供牛馬之食也)

Identification of stars

Before the late Ming dynasty, the identification of the six stars of Chugao was relatively consistent. They are located in Cetus and are generally identified as follows:

Star Names or Orders(Qing)	Han Dynasty (SUN X. & J. Kistemaker)	3rd to 6th Century (Boshun Yang)	Song Dynaty (Boshun Yang, 1034 CE)	Song Dynasty (Pan Nai, 1052 CE)	Song Dynasty (Boshun Yang, 1052 CE)	Qing Dynaty (Yi Shitong, 18th Century)
1st	67 Cet	HIP 11029	HIP 11029 (determinative)	HIP 11029	HIP 11029	ρ Cet
2nd	77 Cet	HIP 12444	HIP 12444	HIP 12444	HIP 12444	77 Cet
3rd	HIP 11029	ρ Cet	ρ Cet	ρ Cet (determinative)	ρ Cet (determinative)	67 Cet
4th	ε Cet	ε Cet (determinative)	ε Cet	ε Cet	ε Cet	71 Cet
5th	ρ Cet	σ Cet	σ Cet	HIP 11348	σ Cet	HIP 11029
6th	σ Cet	HIP 12562	HIP 12562	σ Cet	HIP 12562	ε Cet

Maps (Gallery)

historical map	modern identification	same in Stellarium
		Chugao before later Ming dynasty in Stellarium, with early (before the Northern Song Dynasty) forms of connections Chugao in Stellarium, with the connection form in the late period (Northern Song Dynasty and later)
		Chugao in Qing dynasty (18th century) in Stellarium

IAU Working Group on Star Names

In 2026, the name of the historical constellation "Chugao" was suggested to be used for ρ Ceti in this constellation, as it is the determinative star in the Northern Song Huangyou star catalogue, and among the historical determinative stars across successive dynasties it is the most suitable in terms of brightness.

Decision: ...

References

References (Chinese) [[Category: ]]