What methodological shift did Galileo’s work establish in astronomy after 1610?

Reliance on empirical measurement and repeated observation

The advent of reliable telescopic observation initiated a critical paradigm shift in the methodology of astronomy, moving it away from purely philosophical or geometric reasoning toward an empirically grounded science. Before this period, accepted authority and the aesthetic perfection of mathematical models often held precedence over direct visual evidence, meaning observations contradicting established ideas were often dismissed as perceptual errors. Galileo's successful documentation, especially in *Sidereus Nuncius*, established the telescope as the indispensable instrument for acquiring truth about the cosmos. This practice cemented the necessity of verifiable, repeatable measurement and observation as the ultimate arbiter for understanding the physical reality of the heavens, thus initiating the transition into experimental science.