The Star Manual of Master Shi is an ancient Chinese star catalog now claimed by astronomers at the Chinese National Astronomical Observatories (NAO) to be the oldest surviving star catalog globally. Dating back to around 355 BC, this manuscript predates previously known structured star catalogs by centuries. It reflects a sophisticated astronomical tradition that connected celestial observations with imperial governance, a system maintained by Chinese bureaucrats for nearly two millennia.
Celestial Symbolism Rooted in Imperial Culture
The catalog features constellations depicting an imperial court in the sky, including an emperor’s chariot, a celestial marketplace, and even a star representing a toilet with excrement. These images highlight how early Chinese astronomers, possibly including Shi Shen—an influential astrologer from the Warring States period—organized the night sky into symbolic forms reflecting earthly structures. The system linked heavenly omens to the emperor’s mandate, allowing court astrologers to interpret cosmic events as guidance for maintaining harmony on Earth.
The catalog survived through multiple centuries via careful copying and preservation. Around the third century AD, an astronomer recopied Shi’s data or work inspired by his school, which was further preserved during the Tang dynasty (618–907 AD). Some manuscripts were discovered centuries later, including one reportedly found in the belly of a Buddha statue roughly 400 years ago.
New Computational Methods Reveal Dating and Updates
Astronomers Boliang He and Yongheng Zhao from NAO used a computational algorithm based on the Generalized Hough Transform, an image-processing technique, to analyze historical star catalogs. Their algorithm processes ancient star coordinates, filters out corrupted or erroneous data, and estimates the celestial North Pole’s historical position to date the catalog accurately.
Their analysis suggests that about half of the star positions in the Star Manual of Master Shi date back to approximately 355 BC, corresponding to the era of Shi Shen. The other half appear to have been updated around 125 AD likely during the Eastern Han dynasty, when astronomers, including the famous Zhang Heng—an inventor of the armillary sphere and twice Grand Astrologer (Taishi Ling)—systematically incorporated new observations. This layered composition explains inconsistencies in star positions noted in previous studies.
Scholarly Debate on Accuracy and Dating
Despite this breakthrough, the catalog’s dating remains debated. Historian Boshun Yang argues that many of the older star positions could result from measurements taken with a misaligned instrument, possibly off by about one degree from the true celestial north pole. Such misalignment would skew the perceived precession, creating two distinct clusters of dates in the catalog’s star positions.
Yang and others suggest the catalog’s spherical coordinate system aligns better with a first-century BC origin, when the armillary sphere was invented and a spherical cosmological model adopted in China. This model replaced earlier conceptions of a flat universe, marking a significant shift in Chinese astronomy. Daniel Patrick Morgan, historian at France’s Center for Research on East Asian Civilizations, compares the idea of a 4th-century BC spherical coordinate system to “finding a gas station receipt from 1700,” emphasizing the challenge this early dating poses to conventional historical understanding.
Placing the Catalog in Global Astronomical History
If confirmed, the Star Manual of Master Shi would be older than the Greek Hipparchus catalog from about 130 BC , which has long been considered the earliest structured star catalog in Western astronomy. While Babylonian star records date back to the 8th century BC and note when stars rise, these do not feature the detailed graphical layouts and coordinate systems seen in the Chinese catalog.
The catalog’s survival and updates over centuries reflect a continuous tradition of Chinese astronomy that influenced scientific development far beyond its origins. Researchers He and Zhao plan to apply their methods to other traditional Chinese star catalogs and explore later periods, including the Ming dynasty era when Chinese and Western astronomy first interacted.
Their work aligns with broader cultural aims to highlight China’s scientific heritage and promote cross-cultural exchange, echoing Chinese President Xi Jinping’s call for “civilizations [to] thrive through mutual exchange and learning.”
This study is currently under review by the journal Research in Astronomy and Astrophysics and adds a new chapter to the understanding of humanity’s oldest astronomical records.