Discussant: Mathieu Ossendrijver (Freie Universität Berlin)

This article argues that medieval Chinese star charts were intended to construct a “celestial norm,” a culturally authorized and operational model of the heavens for use in astral practice, rather than to objectively reproduce the visible sky. Focusing on the Sui–Tang period, it reinterprets the relationship between accuracy and idealization by showing that they functioned as complementary epistemic virtues. Positional reliability enabled the identification of stars and the recording of celestial anomalies, while deliberate idealization imposed visual order and enhanced legibility and memorability. Drawing on the history of science, visual studies, and cognitive theory, the article shifts attention from the evaluation of accuracy to the production, use, and transmission of star charts and in so doing proposes a new framework for understanding premodern scientific images.