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(Qinding) Yixiang kaocheng (欽定)儀象考成 "(Imperially endorsed) Compendium of astronomical instruments and observations" is a book on astronomical calculations compiled during the high Qing period 清 (1644-1911) on imperial order by a team of 26 persons under the supervision of Prince Yūn Lu (1695-1767; Ch. Yunlu 允祿) and the Jesuit father Ignaz Kögler (1680-1746; Ch. Dai Jinxian 戴進賢).
In 1744, the Directorate of Astronomy (qintianjian 欽天監) observed that the obliquity of the ecliptic showed a significant difference from what was recorded in the Lingtai yixiang zhi 靈臺儀象志, a treatise on the on the instruments of the Directorate of Astronomy. Additionally, they discovered that the positions of the fixed stars documented in the Lingtai yixiang fa 靈臺儀象法 on calculation methods were inaccurate. Consequently, the Western Director of Directorate (qintianjian Xiyang jianzheng 欽天監西洋監正), the German Jesuit Ignaz Kögler, and others petitioned to revise and expand the star catalog section of the Lingtai yixiang zhi. The compilation of the book of 32 juan was completed in 1752.
When the book was printed and published by the Wuying Hall 武英殿, it coincided with the completion of an armillary sphere called jiheng fuchen yi 璣衡撫辰儀, a large astronomical device that took ten years to manufacture. As a result, two additional fascicles, Jiheng fuchen yi 璣衡撫辰儀, and the commentary Yishuo 議說, were added to the work.
The first two juan describe the functions and usage of the armillary sphere, while the remaining chapters consist of a star catalog (Xingbiao 星表), with the year 1744 as the year of reference (liyuan 曆元). The catalog records 3,083 stars across 300 constellations, including 23 constellations and 150 stars near the South Pole, as well as an "additional" 1,614 stars (zengxing 增星) that were not part of the traditional Chinese star constellations. They were given directional markers and numerical identifiers (fangxiang he shuzi bianhao 方向和數字編號). The star catalog provides the ecliptic and equatorial coordinates (huangdao zuobiao yu chidao zuo biaozhi 黃道坐標與赤道坐標值) for each star, along with the precession of the equinoxes (chidao suicha 赤道歲差) and the magnitude (xingdeng 星等) of each star.
The compilation was based on actual observations and drew references from the revised edition of the British star catalogue of John Flamsteed (1646-1719).
The book was first printed in 1757 and is included in the series Siku quanshu 四庫全書 and Chizaotang siku quanshu huiyao 摛藻堂四庫全書薈要.
A further, revised official print (dianben 殿本) was published in 1845 with the title Yixiang kaocheng xubian 儀象考成續編. The chief editor of this star catalog was Zhou Yuqing 周余慶, the Director of the Directorate of Astronomy (qintianjian jianzheng 欽天監監正) and Assistant Supervisor of Mathematics at the Directorate of Education (xieli guozijian suanxue shiwu 協理國子監算學事務). This was the first star catalog independently compiled and calculated by Chinese astronomers.
The catalog added 163 stars compared to the Yixiang kaocheng, while removing six stars that were not observed, resulting in a total of 3,240 stars. The reference year (liyuan) of the catalog was set to the winter solstice of 1844. Although the Yixiang kaocheng houbian did not significantly increase the number of stars or introduce major changes, it provided a set of newly measured stellar coordinates with reliable dating. This allows to assess the measurement accuracy of the Qing dynasty.
The various star catalogs from the Qing dynasty served as a bridge between earlier works and modern astronomy and remain a key reference for the Chinese names of stars still in use today.