Zuogeng (左更) and Yougeng (右更)
Authors: Lyu Haocheng
| Asterism Info | |
| Native | 左更 |
|---|---|
| Romanisation | Zuǒ Gēng |
| IPA | /t͡swo˨˩˦.kɤŋ˥˥/ |
| Translation | Official in Charge of the Forest |
| Position (2000) | |
| Right ascension | 32.65908333 to 39.70729167 |
| Declination | 15.28086111 to 25.04491667 |
| Area | 0 sq. deg. |
| Stars | |
| Bright stars | 5 |
| Bayer/Flamsteed stars | 5 |
| Stars brighter than 3.00m | 0 |
| Brightest star | η Ari (5.20m) |
| Taxonomy | |
| category of asterism | constellation |
| IAU- constellations | Ari |
| Asterism Info | |
| Native | 右更 |
|---|---|
| Romanisation | Yòu Gēng |
| IPA | /joʊ˥˩.kɤŋ˥/ |
| Translation | Official in Charge of Pasturing |
| Position (2000) | |
| Right ascension | 22.87229167 to 29.33983333 |
| Declination | 12.14255556 to 20.27005556 |
| Area | 0 sq. deg. |
| Stars | |
| Bright stars | 5 |
| Bayer/Flamsteed stars | 4 |
| Stars brighter than 3.00m | 0 |
| Brightest star | η Psc (3.62m) |
| Taxonomy | |
| category of asterism | constellation |
| IAU- constellations | Psc |
Zuǒ Gēng (左更, Official in Charge of the Forest) and Yòu Gēng (右更, Official in Charge of Pasturing) are two paired Chinese asterisms belonging to the Lóu (婁, Bond) lunar mansion. Among the Three Schools of ancient Chinese astronomy, both are classified as asterisms of the Gan School (甘氏). Each consists of five stars. Zuogeng is located to the east of Lou (婁), within the modern constellation Aries; Yougeng is located to the west of Lou (婁), within the modern constellation Pisces.
Concordance, Etymology, History
The names Zuogeng and Yougeng derive from the Qin twenty-rank noble system (二十等爵), in which Zuogeng was the twelfth rank and Yougeng the fourteenth, both belonging to the higher echelons of the military nobility. The term geng (更) in this context is related to "shifts" or "watches", reflecting the ranks' association with military duty and rotation. The asterisms thus take their names from official titles, a common naming pattern in Chinese astronomy.
Since the Lou (婁) mansion governs pastures and mountain forests, Zuogeng was established to administer the mountains and forests, and Yougeng to administer the pastures. The Jin Shu·Tianwen Zhi (晉書·天文志, Book of Jin, Treatise on Astronomy) confirms this division of labour:
Five stars east of Lou are called Zuogeng, the Mountain Warden (山虞). Five stars west of Lou are called Yougeng, the Pasture Officer (牧師). (婁東五星曰左更，山虞也；婁西五星曰右更，牧師也。)
The Mountain Warden (山虞) was an official in the Rites of Zhou (周禮) responsible for the administration of mountains, forests, marshes, and the harvesting of timber, bamboo, and vegetables. The Pasture Officer (牧師) governed the herding and breeding of cattle and horses.
The Gan Shi Zan (甘氏讚, Gan's Eulogy) describes Zuogeng as "gathering firewood and harvesting vegetables in the rabbit garden" (左更採薪，菟園採茹) and Yougeng as "servants and livestock, pregnant with heavy calves and foals" (右更僕畜，孕重犢駒也).
The Kaiyuan Zhanjing (開元占經) preserves further astrological interpretations. Xi Meng (郗萌) states that Zuogeng governs the way of benevolence (仁之道) and Yougeng the way of ritual propriety (禮義). The Huangdi Zhan (黄帝占) records that if the stars of either asterism are incomplete, the roads of the realm will be impassable. Jiao Yanshou (焦延壽) adds that when Zuogeng is motionless and Yougeng alone moves, the king will travel in private; when both move, the king will go out with a thousand officials.
Identification of stars
| Star Names or Orders(Qing) | 3rd to 6th Century (Boshun Yang[1]) | Song Dynasty (Pan Nai[2], 1052 CE) | Song Dynasty (Boshun Yang[1], 1052 CE) | Qing Dynaty (Yi Shitong[3], 18th Century) | Ho PENG YOKE[4] | |
|---|---|---|---|---|---|---|
| Zuogeng
（左更） |
1st | θ Ari | HIP 11670 | HIP 11670 | ν Ari | ν Ari |
| 2nd | 15 Ari (determinative) | HIP 10795 | HIP 10795 | μ Ari | μ Ari | |
| 3rd | HIP 9627 | η Ari | η Ari | ο Ari | ο Ari | |
| 4th | HIP 9533 | 15 Ari (determinative) | 15 Ari (determinative) | σ Ari | σ Ari | |
| 5th | 19 Ari | θ Ari | θ Ari | π Ari | π Ari[comment 1] | |
| Yougeng
（右更） |
1st | ι Ari | 107 Psc (determinative) | 107 Psc (determinative) | ρ Psc | ρ Psc |
| 2nd | 107 Psc (determinative) | 97 Psc | HIP 7359 | η Psc | η Psc | |
| 3rd | ρ Psc | 87 Psc | 97 Psc | π Psc | π Psc | |
| 4th | η Psc | η Psc | η Psc | ο Psc | ο Psc | |
| 5th | 4 Ari | HIP 7447[comment 2] | 105 Psc | 104 Psc | ? | |
Maps (Gallery)
| historical map | modern identification | same in Stellarium |
|---|---|---|
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_reconstructed_by_Pan_Nai_(2009).png) _reconstructed_by_Boshun_Yang_(2023).png) |
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IAU Working Group on Star Names
In 2026, the name of the historical constellation "Zuogeng" was suggested to be used for η Arietis in this constellation, as it is the brightest star of the asterism.
Decision: ...
References
- ↑ 1.0 1.1 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.
- ↑ Pan Nai潘鼐. Zhongguo Hengxing Guance shi中国恒星观测史[M]. Shanghai: Xuelin Pree. 1989, Pp220-226.
- ↑ Yi Shitong伊世同. Zhongxi Duizhao Hengxing Tubiao中西对照恒星图表1950. Beijing: Science Press.1981.
- ↑ P.-Y. Ho, “Ancient And Mediaeval Observations of Comets and Novae in Chinese Sources,” Vistas in Astronomy, 5(1962), 127-225.
