Between astronomy and politics: the Petit–Morin polemic over the solar eclipse of 8 April 1652

This article reconstructs a polemic between Pierre Petit and Jean-Baptiste Morin over the eclipse of 8 April 1652. It argues that it constituted an indirect extension of the campaign waged by Gassendi and his circle against Morin and judicial astrology. It further contends that this episode reveals the inseparability of scholarly and political concerns in the processes by which astrology was marginalized in mid-seventeenth-century France. Observed in Paris amid the instability of the Fronde, the eclipse promoted an exchange that ostensibly concerned observational accuracy, instruments, and methods of calculation, but also exposed competing claims to credibility, patronage, and authority to interpret celestial phenomena. Petit observed the eclipse before Cardinal de Retz and an audience, whereas Morin conducted his observation at the Palais d’Orléans under Gaston d’Orléans’s patronage. Through his satirical Apotelesma, Petit imitated the conventions of astrological prognostication only to replace celestial influence with terrestrial political causation. Morin, by contrast, defended the eclipse’s astrological significance by connecting it to Condé’s victory at Bléneau. The polemic challenges interpretations that locate astrology’s marginalization primarily within learned disputes over Copernicanism, showing instead how astronomical practice, social authority, political conflict, and theological concerns converged.