Gang (槓)

New Reconstruction of Huagai and Gang (before Tang Dynasty) By Boshun YANG

Gàng (Canopy Shaft, 槓) comprises nine stars and forms an integral part of the asterism Huagai (華蓋)(Canopy of the Emperor). The configuration of this sub-asterism varied across historical sources: in its earliest form, it was located in the region of the modern constellation Cepheus, but later shifted toward Cassiopeia and Camelopardalis. It originated within the Gan school during the Han dynasty, around the first century BCE.

Concordance, Etymology, History

Identification of stars

Earlier research by Yang (2023) reconstructed the early Huá Gài and Gàng asterisms in a form that closely reflects their physical appearance. More recently, however, he further noticed a passage in the Commentary to the Gan’s Star Canon (Gān shi zan, 甘氏赞), which reads:

“The Canopy shines with light, overshadowing the Emperor's body; its dark  ribs (liǎo, 橑) encircle the Shaft, and it sits on two pillars.”

華蓋曜光，掩翳帝軀，玄橑周杠，兩植距趺。

This description provides valuable information about both the function and structure of Huá Gài:  the Huá Gài canopy was imagined as having multiple ribs radiating outward from its shaft (gàng, 杠), and the upper end of the Gàng was imagined as having two supporting points.

In Yang’s earlier reconstruction (2023), only one support point—HIP 111660—was included. In light of the textual evidence from the Commentary, it now seems appropriate to add a second support star, 78 Draconis. This adjustment not only accords more closely with the Commentary’s description but also matches the depiction on the Cheonsang Yeolcha Bunyajido. However, correspondingly, it is necessary to remove another star original included in Gang, and removing HIP 112833 is more appropriate.

Constellation	Star Names or Orders(Qing)	Yi Shitong Based on catalogue in 18th century	Pan Nai based on Xinyixiangfayao Star Map	SUN X. & J. Kistemaker Han Dynasty	Boshun Yang before Tang dynasty	Boshun Yang Song Jingyou(1034)	Boshun Yang Song Huangyou(1052)
Huagai	1st(Determinative)		iota Cas	omega Cas	16 Cep	omega Cas	iota Cas
	2nd	40 Cas	40 Cas	49 Cas	gamma Cep	31 Cas	RZ Cas
	3rd	HIP 5926	42 Cas	40 Cas	pi Cep	psi Cas	SU Cas
	4th	31 Cas	omega Cas	42 Cas	31 Cep	43 Cas	HIP 12821
	5th	psi Cas	HIP 12821	HIP 12821	24 Cep	iota Cas	omega Cas
	6th	43 Cas	SU Cas	SU Cas	11 Cep	HIP 12821	42 Cas
	7th	omega Cas	A Cas	A Cas	betta Cep	SU Cas	A Cas
Gang	1st(Determinative)	gamma Cam	49H Cep 48(HIP 19461)	50 Cas	HIP 5928	HIP 25110	HIP 19461
	2nd	HIP 14862	HIP 14844	HIP 12273	HIP 115746	HIP 23265	HIP 14844
	3rd	49 Cas	46H Cep 30 (HIP 13055)	HIP 14862	HIP 109693	HIP 20776	HIP 13055
	4th	51 Cas	HIP 9568	HIP 15547	HIP 112833	HIP 19461	HIP 9568
	5th	50 Cas	47 Cas	HIP 14417	HIP 113116	HIP 14417	47 Cas
	6th	54 Cas	49 Cas	HIP 19461	HIP 112519	50 Cas	49 Cas
	7th	A Cas	HIP 10350	HIP 20776	rho Cep	A Cas	HIP 10350
	8th	42 Cas	50 Cas	HIP 23265	HIP 111242	42 Cas	HIP 12273
	9th	38 cas		HIP 25100	HIP 111660	38 Cas	50 Cas

Maps (Gallery)

historical map	modern identification (Yang 2023)	same in Stellarium 25.3
Huagai and Gang on Cheonsang Yeolcha Bunyajido	Huagai and Gang before Tang Dynasty Reconstructed by Boshun Yang (2023)	Huagai, Gang and a few neighbouring asterisms before Tang Dynasty in Stellarium
Huagai and Gang on Dunhuang Star Map	Huagai and Gang in Early Song Dynasty (1034CE) Reconstructed by Boshun Yang (2023)	Huagai, Gang and a few neighbouring asterisms in 1034 in Stellarium
Huagai and Gang on Geziyuejintu
Huagai and Gang on Suzhou Star Map	Huagai and Gang in Huangyou Era in Song Dynasty (1052CE) Reconstructed by Boshun Yang (2023)	Huagai, Gang and a few neighbouring asterisms in 1052 in Stellarium
Huagai and Gang in 18th Century Star Map	Huagai and Gang in 18th Century Reconstructed by YI Shitong (1981)	Huagai, Gang and a few neighbouring asterisms in 18th Century in Stellarium

Star Name Discussion (IAU)

In 202x, the name of the historical constellation "xxx" was suggested to be used for one of the stars in this constellation. ...

Decision: ...

References

References (Chinese)