Delineating Boundaries of Chinese Xingguans

摘要: Around the asterisms (星官) of Chinese astronomical culture, linear-rectangular spherical polygons are delineated along celestial lines of right ascension and declination into 359 boundaries to establish, for the first time, a complete set of 321 Chinese constellations. The term "asterism" is coined from "star" and "bureaucrat" to describe an identifiable arrangement pattern of stars or asterisms in the night sky. All boundaries of the Chinese constellations seamlessly partition the celestial sphere into star regions, star fields, and star areas nested in a three-tier hierarchy. At the top level are six regions: two polar regions and four zodiac quadrant regions metaphorically represented by four cultural totems (四象). The middle layer subdivides these regions into 32 fields that epitomise ancient Chinese society, including the Three Enclosures (三垣), the Twenty-Eight Mansions (二十八宿), and the near-south-pole starry field. At the bottom level, the fields are further partitioned into 321 individual areas, each encompassing a unique asterism. The boundary of each area delineates an exclusive "star constituency" for the asterism, such that all points or stars within the star area unambiguously belong to the constituency, thereby establishing a Chinese constellation. The delineation of the boundaries is based on 3,325 ascertained bright stars that compose all the asterisms in the hierarchy, most of which are catalogued in Yi Xiang Kao Cheng (仪象考成, 1752) and its continued edition Yi Xiang Kao Cheng Xu Bian (仪象考成续编, 1844). The astronomical information of these stars is cross-verified against modern star catalogues, and their positions are validated via the astronomical database systems SIMBAD and VizieR. The coordinates are converted into ICRS J2000.0 data. The boundary data is formatted in compliance with the Flexible Image Transport System (FITS) standards for legitimate data storage and network transmission in modern applications. The boundaries are tabulated using a smart computational algorithm pioneered by Nancy Grace Roman (1987) for indexing a boundary by celestial position. Parametric computations are also provided to determine the barycentres, areas (in square radians and square degrees), ranking ratios, and visibility of the Chinese constellations. With unambiguous boundaries, the Chinese constellations emerge as a modern digital infrastructure that facilitates high-resolution, rapid mapping of spheroidal pixelisation of the celestial sky, enables the integration of asterisms into modern astronomy, contributes to the preservation and protection of Chinese astronomical cultural heritage, and brings Chinese starry sky narratives into astronautical engineering and space technology.