Summary

In 2025, the Paris Observatory celebrates the 400th anniversary of Jean Dominique Cassini’s birth.
To mark the occasion, we are organizing a symposium that will take stock of current research on Cassini, along four lines (institutional history, history of science, history of art, historiography) that we detail in the scientific justification.
The symposium will be coupled with an exhibition at the Observatory Library, based on original manuscripts by J. D. Cassini.

Scientific justification

The work of Jean-Dominique Cassini (June 8, 1625 - September 14, 1712) in the field of astronomical science took place during a period of profound change, marked in particular by instrumental developments, new methods of observation, new theories and the emergence of scientific institutions. From his first publications in the 1660s, and throughout his almost forty years at the Paris Observatory, J. D. Cassini was a key player in these developments. This symposium takes the opportunity of the 400th anniversary of the astronomer’s birth to take stock of this major contribution, examining it from four angles.
*Institutional. The work will be seen in the context of the Paris Observatory and the Royal Academy of Sciences of the time, European networks and learned societies, and inventories of Cassini’s archives held in current institutions.
*Scientific. Cassini’s contribution to astronomical observations, geodesy, gnomonics, meteorology, etc., and the posterity of his work in the 18th century will be discussed, based in particular on original archives and his academic publications.
*Art history. This section will focus on iconographic aspects, from the creation of the handwritten observational drawing to its printing, evoking the creation of celestial and geographical maps, and the contributions of artists and engravers;
*Historiographical. This theme will focus on Cassini’s contribution to the history of astronomy, in particular through an examination of his sources, a contextualization of his work as a historian, and a study of the posterity of his work.

Preliminary program

Tuesday June 10th
Institutions and archives
Riccardo Balestrieri (Independent researcher, San Marino): Prima di Bologna: la giovinezza di Gio. Domenico Cassini
Guy Picolet (Centre Alexandre Koyré): J.-D. Cassini at the Royal Observatory (1671-1712)
Gastaldi Nadine (Archives nationales, Paris) Les Cassini aux Archives nationales: les administrateurs, les savants, les hommes
Véronique Stoll, Aleth Tisseau des Escotais (Paris Observatory Library, Paris): Inventory of the archives
David Aubin (IMJ-PRG, Paris): Incursions into the Cassini library. What a sales catalog reveals
Sciences
Denis Savoie (LTE, Paris): History of Cassini’s San Petronio meridian Matthieu Husson (LTE, Paris): Tables on the satellites of Jupiter
Christophe Schmit (LTE, Paris): The academic memoirs of J. D. Cassini
Wednesday June 11th
Art/visual practices
Katherine Reinhart (Binghamton University, State University of New York): Visual Practices in the World of Cassini
Antoine Gallay (University of Lausanne) : Cassini’s Lunar Print and the Cabinet du Roi : The Failure of a Grand Project ?
Nydia Pineda de Avilla (University of California - San Diego): Selenography in Cassini’s Knowledge Networks
Historiography and reception
Giorgio Matteoli (University of Turin): Cassini and the history of astronomy (or, Ad maiorem Ludovici gloriam) Florence Hsia (University of Wisconsin): Cassini’s memoir on astronomy in Siam
Huiyi Wu (Centre A. Koyré, Paris), Colette Le Lay (Centre François Viète, Nantes), Christophe Schmit (LTE, Paris): J. D. Cassini in the Encyclopédie: reception of cartographic and astronomical works
Dalia Deias (Centre Alexandre Koyré, Paris) : Giovanni Domenico Cassini au prisme des historiographies : sciences et politiques du XVIIe siècle à nos jours