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{{DISPLAYTITLE: Zigong (紫宮)}}

''Zǐ Gōng (Purple Palace, 紫宮)''—also known as ''Zǐwēi Gōng'' (Purple Forbidden Palace, 紫微宮) or ''Zǐwēi Yuán'' (Purple Forbidden Enclosure, 紫微垣)—symbolizes the imperial residence and its surrounding guarding vassals or ministers. It is a nearly circular circumpolar region encompassing fifteen stars, which are divided into two parts: the seven stars of the ''Dōng Fān'' (Eastern Retinue, 東蕃) and the eight stars of the ''Xī Fān'' (Western Retinue, 西蕃). 

== Concordance, Etymology, History ==
''Zǐ Gōng'' (“Purple Palace”) is the oldest among the constellation’s names, literally meaning “the purple palace.” Prior to and throughout the Tang dynasty, this was the most prevalent term and remained in use into the Song period.

During the Spring and Autumn period (770 - 476 BCE), purple was a fashionable color in clothing but was rejected by Confucians as a “non-proper hue.” In the Qin and Han periods, despite continuing condemnation by orthodox Confucian scholars, purple came to be associated with mystery and imperial dignity<ref>Zeng Lei. The Evolution of the Concept of Purple in the Qin and Han Dynasties [J]. ''Shixue yuekan'', 2013, (02): 121-125</ref>.

Palatial architecture in the Qin and Han dynasties was often conceived as a terrestrial imitation of celestial patterns. The ''Sanfu Huangtu'' (Yellow [i.e. imperial] maps of the three metropolitan areas, 三輔黃圖) records that Emperor Qin Shihuang “constructed the Xianyang Palace in accordance with the pattern of the Purple Palace, emulating the residence of the Emperor [in Heaven].<ref>Chen Zhi, ''Sanfu Huangtu Jiaozheng'', vol. 1, p. 6, Shaanxi People’s Press, 1980</ref> If this account is reliable, the costellation of ''Zigong'' already existed in the Qin period.

We are quite sure that the Zigong appears no later than the early Western Han. The ''Huainanzi'' states: “The Purple Palace is the dwelling of the Great One (Taiyi).” Similarly, the ''Tiānguān shu'' (''Book of Heaven Officials'', 天官書) notes: “Encircling it [the Pole Star, residence of the Taiyi deity] are twelve stars of protection—vassals—together called the Purple Palace.” In the early Western Han, ''Zigong'' and ''Taiwei'' (Supreme Court, 太微) each comprised twelve stars, possibly corresponding to the twelve gates of the Han capital Chang’an. Ban Gu’s ''Rhapsody on the Eastern Capital'' (''Dongdu fu'') further confirms this correspondence, describing the palaces of Chang’an as “occupying the central position of Earth’s numinous axis, modeled after the circular and square forms of the Supreme Court and the Purple Palace”<ref>''Hou Han shu'', “Biography of Ban Gu I,” p. 1340</ref> .

By the mid-Western Han, the Shi school renamed the asterism as ''Zǐwēi Gōng'', expanding it to fifteen stars. This nomenclature was soon adopted by the Gan school and by various apocryphal (weishu, 緯書) texts. Before the Tang dynasty, ''Zǐwēi Gōng'' remained the official term. The name ''Zǐwēi Yuán'' first appeared in non-astronomical writings during the Northern and Southern dynasties, later entering official astronomical records in the late Tang period. After the Song dynasty, ''Zǐwēi Yuán'' became the most widespread designation.

=== Member Star Names ===
Each of the fifteen stars in the ''Zǐwēi Enclosure'' bears an individual name. The designations most familiar today—such as ''Zuǒ Shū'' (Left Pivot), ''Shào Chéng'' (Junior Minister), and ''Shàng Wèi'' (Upper Guard)—are recorded in astronomical poets like the ''Bùtiān gē'' (Song of Pacing the Sky, 步天歌) but only became common from the mid-Tang period onward.

In the Han (202 BCE - 220CE) to Jin(266 - 420) periods, an entirely different naming system was in use. The ''Tianwen yaolu'' (Essentials of Astronomy, 天文要錄) preserves these earlier designations through quotations from pre-Tang sources:

<blockquote>'''The ''Eastern Retinue'' of the Purple Palace:'''

''Tóuguān'' (First Observatory, 頭觀), governing benevolence and charity;

''Qìngmén'' (Celebration Gate, 慶門), governing propriety and self-cultivation;

''Pànxīng'' (Academy Star, 泮星), governing kindness and action;

''Kāifān'' (Prosperous Frontier, 開蕃), governing rebellious schemes;

''Lóngdēng'' (Dragon Ascendant, 龍登), governing agriculture;

''Gǎnxīng'' (Valiant Star, 敢星), governing palaces and architecture;

''Guāngbó'' (Lord of Light, 光伯), governing drought and famine;

''Shùnguāng'' (Harmonious Radiance, 順光), governing military affairs.

'''The ''Western Retinue'':'''

''Shǒumén'' (Gatekeeper, 守門), governing wind and water;

''Zǐmíng'' (Catalpa Brightness, 梓明), governing illness;

''Jiān xīng'' (Treacherous Star, 姧星), governing debauchery;

''Zhímén'' (Straight Gate, 直門), governing joy and affection;

''Zǐguāng'' (Purple Radiance, 紫光), governing fidelity;

''Tónglíng'' (Phoenix Tree Mound, 桐陵), governing intelligence and order;

''Xìnguī'' (Trustworthy Turtle, 信龜), governing ritual virtue.

</blockquote>These names, largely forgotten after the Tang, reveal the early Han cosmological association of each star with moral and political virtues.

== Identification of stars ==
According to Yang and Hoffmann (2024)<ref>[https://www.raa-journal.org/issues/all/2024/v24n12/202412/t20241216_278177.html] Bo-Shun Yang and Susanne M. Hoffmann 2024 ''Res. Astron. Astrophys.'' 24 125004</ref>, the shape of the ''Zǐwēi Enclosure'' underwent significant transformation from the Han to the Song dynasty. Two major changes can be identified:

'''Expansion of the northern boundary'''—Originally nearly circular, the enclosure became elongated, extending northward.

'''Reconfiguration of the southern gates'''—The stars marking the east and west gates changed from α Draconis and 6 Draconis to ι Draconis and α Draconis.

The first alteration likely resulted from the gradual precession of the north celestial pole. During the Early Han period, the pole lay at the center of the ''Purple Palace'', but by the Tang–Song era it had drifted so far that it locates near the northern gate. Astronomers, whether consciously or not, extended the northern arc of the enclosure to realign its center with the celestial pole.

The second adjustment was probably a structural consequence of the first. Once the enclosure was elongated, its “gates” needed to be repositioned along the new major axis, to preserve axial symmetry and conform to ritual propriety. This transformation effectively rotated the entire ''Zigong'' about 45 degrees counterclockwise, also altering the directional references used for neighboring asterisms. For instance, the ''Běidǒu'' (Northern Dipper) asterism—originally described as lying “south” of the ''Zǐwēi Enclosure''—was, from the Song period onward, described as being on its “right.”
{| class="wikitable"
|+
!Constellation Name
!Orders(Qing) or Star Names(Song and After;Tang and Before)
!Ho PENG YOKE<ref>P.-Y. Ho, “Ancient And Mediaeval Observations of Comets and Novae in Chinese Sources,” ''Vistas in Astronomy'', 5(1962), 127-225.</ref>
!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: 56.</ref>
Based on catalogue in 18th century
!Pan Nai<ref name=":0">Pan Nai潘鼐. ''Zhongguo Hengxing Guance shi''中国恒星观测史[M]. Shanghai: Xuelin Pree. 1989. p226.</ref>
based on Huangyou Star Catalogue (1052)
!Pan Nai<ref>Pan Nai潘鼐. ''Zhongguo Hengxing Guance shi''中国恒星观测史[M]. Shanghai: Xuelin Pree. 2009. p443.</ref>
based on catalogues in Yuan dynasty
!SUN X. & J. Kistemaker<ref>Sun Xiaochun. & Kistemaker J. ''The Chinese sky during the Han''. Leiden: Brill. 1997, Pp241-6.</ref>
Han Dynasty
!Boshun Yang<ref name=":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). 238.</ref>
before Tang dynasty
!Boshun Yang<ref name=":1" />
Song Jingyou(1034)
|-
| rowspan="9" |Dongfan(Eastern Retinue) or Zuoyuan(Left Wall)
| 1st(Zuoshu, 左樞；Touguan, 頭觀 )
| iota Dra
| iota Dra
| iota Dra
| iota Dra
| alpha Dra
| alpha Dra
| iota Dra
|-
| 2nd(Shangzai, 上宰; Qingmen, 慶門)
| theta Dra
| theta Dra
| theta Dra
| theta Dra
| iota Dra
| iota Dra
| theta Dra
|-
| 3rd(Shaozai, 少宰; Panxing, 泮星)
| eta Dra
| eta Dra
| eta Dra
| eta Dra
| theta Dra
| theta Dra
| eta Dra
|-
|4th(Shangbi, 上弼; Kaifan, 開蕃)
| zeta Dra
| zeta Dra
| zeta Dra
| zeta Dra
| eta Dra
| eta Dra
| zeta Dra
|-
|5th(Shaobi, 少弼; Longdeng, 龍登)
|upsilon Dra
|upsilon Dra
|phi Dra
|phi Dra
|zeta Dra
|zeta Dra
|phi Dra
|-
|6th(Shangwei, 上衛; Ganxing, 敢星)
|beta Cep
|73 Dra
|kappa cep
|73 Dra
|phi Dra
|omega Dra
|tau Dra
|-
|7th(Shaowei, 少衛; Guangbo, 光伯)
|pi Cep
|pi Cep
|rho Cep
|gamma Cep
|73 Dra
|phi Dra
|73 Dra
|-
|8th(Shaocheng, 少丞; Shunguang, 順光)
|gamma Cep
|23 Cas
|HIP 6522
|21 Cas
|pi Cep
|HIP 92056
|pi Cep
|-
|
|
|
|
|
|23 Cas
|
|
|-
| rowspan="7" |Xifan(Western Retinue) or Youyuan (Right Wall)
|1st(Youshu,右樞; Shoumen, 守門）
|alpha Dra
|alpha Dra
|alpha Dra
|alpha Dra
|kappa Dra
|6 Dra
|alpha Dra
|-
|2nd(Shaowei, 少尉; Ziming, 梓明)
|kappa Dra
|kappa Dra
|kappa Dra
|kappa Dra
|lambda Dra
|lambda Dra
|kappa Dra
|-
|3rd(Shangfu, 上輔; Jianxing, 姧星)
|lambda Dra
|lambda Dra
|lambda Dra
|lambda Dra
|d Uma
|HIP 52425
|lambda Dra
|-
|4th (Shaofu, 少輔; Zhimen,  直門)
|d Uma
|d Uma
|d Uma
|d Uma
|43 Cam
|27 Uma
|HIP 52425
|-
|5th(Shangwei, 上衛; Ziguang, 紫光)
|43 Cam
|43 Cam
|HIP 33827
|HIP 29997
|alpha Cam
|HIP 40793
|27 Uma
|-
|6th(Shaowei, 少衛; Tongling, 桐陵)
|alpha Cam
|alpha Cam
|BN Cam
|gamma Cam
|BK Cam
|HIP 33694
|HIP33694
|-
|7th(Shangcheng, 上丞; Xingui, 信龜)
|BK Cam
|BK Cam
|HIP 14862
|HIP 12273
|
|HIP 25110
|HIP 17862
|}

=== Maps (Gallery) ===
{| class="wikitable"
|+
!historical map
!modern identification
(Yang 2023)
!same in Stellarium 24.4
|-
|[[File:Purple Palace in Cheonsang Yeolcha Bunyajido.png|thumb|Purple (Forbidden) Palace in ''Cheonsang Yeolcha Bunyajido'']]
|[[File:Purple (Forbidden) Palace before Tang dynasty reconstructed by Boshun Yang (2023).png|thumb|Purple (Forbidden) Palace before Tang dynasty reconstructed by Boshun Yang (2023)]]
|[[File:Purple (Forbidden) Palace before Tang dynasty in Stellarium.jpg|thumb|Purple (Forbidden) Palace before Tang dynasty in Stellarium]]
|-
|[[File:Purple Palace in Suzhou Star Map.png|thumb|Purple (Forbidden) Palace in Suzhou Star Map]]
|[[File:Purple (Forbidden) Palace in Song dynasty (1052) reconstructed by Boshun Yang (2023).png|thumb|Purple (Forbidden) Palace in Song dynasty (1052) reconstructed by Boshun Yang (2023)]]
|[[File:Purple (Forbidden) Palace in Song dynasty (1052) in Stellarium.png|thumb|Purple (Forbidden) Palace in Song dynasty (1052) in Stellarium]]
|-
|
|[[File:Purple (Forbidden) Palace in Late Yuan dynasty (about 1363) reconstructed by Boshun Yang (2023).jpg|thumb|Purple (Forbidden) Palace in Late Yuan dynasty (about 1363) reconstructed by Boshun Yang (2023)]]
|[[File:Purple (Forbidden) Palace in Late Yuan dynasty (about 1363) in Stellarium.jpg|thumb|Purple (Forbidden) Palace in Late Yuan dynasty (about 1363) in Stellarium]]
|-
|[[File:Purple Forbidden Palace in 18th Century Star Map.jpg|thumb|Purple (Forbidden) Palace in 18th Century Star Map]]
|[[File:Purple (Forbidden) Palace in 18th Century Reconstructed by YI Shitong (1981).jpg|thumb|Purple (Forbidden) Palace in 18th Century Reconstructed by YI Shitong (1981)]]
|[[File:Purple (Forbidden) Palace in 18th Century in Stellarium.jpg|thumb|Purple (Forbidden) Palace 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)]]


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