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步天歌

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Text ID
KR3fa005
Date
712–762
Dynasty
唐

Bùtiān gē 步天歌

Song of the Pacings of Heaven by 王希明 (撰)

About the work

The Bùtiān gē 步天歌 (“Song of Pacing through the Heavens”) is the most influential pre-modern Chinese star-catalog in mnemonic verse form. It enumerates and locates every one of the 283 traditional Chinese asterisms (xīngguān 星官, totalling roughly 1,464 individual stars) of the Three Enclosures (sānyuán 三垣 — Zǐwēi 紫微, Tàiwēi 太微, Tiānshì 天市) and the Twenty-Eight Lunar Lodges (èrshíbā xiù 二十八宿), in clear seven-character lines designed to be recited and memorised. For more than a thousand years it was the principal pedagogical tool by which the Chinese sky was taught to court astronomers, calendrical officials and educated amateurs.

Abstract

The work is attributed by the Sòngshǐ 宋史 yìwén zhì and by the Sòng Yùhǎi 玉海 of 王應麟 to a Táng-period imperial expert 王希明 Wáng Xīmíng, an internal-service Hànlín on-call attendant (Nèigòngfèng dàizhào Hànlín 内供奉待詔翰林) active in the Kāiyuán era (713–741) of Tang Xuánzōng. (Some Sòng and Yuán sources alternatively attribute it to “Dānyuánzǐ” 丹元子 — variously identified with Wáng Xīmíng or with an earlier SuíTáng figure named Yǔ Jì 鄭茂 / 王善祈, on which see the discussion in Sìkù tíyào and in Sun Xiaochun & Kistemaker 1997.) The composition window adopted here (Kāiyuán + early Tiānbǎo, 712–762) follows the dominant Wáng Xīmíng attribution.

The text is divided into 31 sections following the orthodox Chinese celestial division — three enclosures plus twenty-eight lodges — each composed of strict seven-character rhyming lines. For each asterism the verse gives the name, the number of stars, and the topological relation to neighbouring asterisms in a way that allows the reader to “walk” 步 from one to the next around the sky. The earliest extant version is found in the Lìngtiān jiàn shū 靈臺秘苑 type of Táng astronomical compendia and in the Dūnhuáng MS S.3326 (“Dūnhuáng star chart”) of the 7th-8th century, the oldest surviving graphical star map in any culture, which is closely related to the Bùtiān gē tradition.

The Sòng-era authority on it is 蘇頌 Sū Sòng’s Xīnyí xiàng fǎ yào 新儀象法要 (1094), which uses the Bùtiān gē asterism inventory as its observational framework. From the Sòng onward every Chinese star map and every imperial Tiānwén zhì (astronomical treatise in the dynastic histories) takes the Bùtiān gē sky as base; the Yuán Suzhou Pínjiāngfǔ stone planisphere of 1247 (淳祐天文圖, attrib. Huáng Shang 黃裳 1190) follows it directly. The text was incorporated into the Sìkù quánshū.

Translations and research

  • Sun Xiaochun and Jacob Kistemaker. 1997. The Chinese Sky During the Han: Constellating Stars and Society. Leiden: Brill. — definitive English-language reconstruction of the pre-modern Chinese sky; uses the Bù-tiān gē asterism inventory throughout and gives identifications to modern catalog stars.
  • Pan Nai 潘鼐. 1989. Zhōngguó héngxīng guāncè shǐ 中國恆星觀測史. Shanghai. — the standard Chinese-language history of stellar observation; chapter 4 is devoted to the Bù-tiān gē.
  • Joseph Needham. Science and Civilisation in China, vol. III: Mathematics and the Sciences of the Heavens and the Earth, Cambridge 1959, 277–284 — discusses the Bù-tiān gē with a partial translation of the Zǐ-wēi section.
  • Bonnet-Bidaud, J.M., F. Praderie, S. Whitfield. 2009. “The Dunhuang Chinese sky: a comprehensive study of the oldest known star atlas.” Journal of Astronomical History and Heritage 12.1: 39–59. — relates the Dunhuang star atlas (S.3326) to the Bù-tiān gē tradition.
  • 陳遵媯 Chén Zūnguī. 1980. Zhōngguó tiānwénxué shǐ 中國天文學史, vol. 2 (恆星卷). Shanghai: Shanghai rénmín. — extensive treatment.

Other points of interest

The Bùtiān gē is remarkable as a culturally durable example of the use of verse as a working scientific notation: the same text was recited at the Táng Imperial Astronomical Bureau (sītiānjiān 司天監), at the Sòng Hànlín tiānwén yuàn, and in early-Qīng Catholic Jesuit-Chinese astronomical pedagogy alongside Verbiest’s Língtái yíxiàng zhì KR3fa021. The pedagogical advantage — that a memorised verse can be recited under observation in the dark — explains its longevity.

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