ESHS/HSS Annual Meeting

Reconstructing the Birth of Transient Astronomy in the Age of Cassini

• In Event: Scientific Disputes, Cosmological Theories from Scheiner to Cassini: Archival Sources from the 17th Century 2

English Abstract

In the second half of the 17th century, Italy experienced a second astronomical revolution driven by Galileo's scientific principles and telescopic observations. This observational golden age, spearheaded by the charismatic Giovan Domenico Cassini, swiftly spread throughout Europe, establishing a robust planetary astronomy based on the celestial mechanics of Kepler and Newton.
Less well known is the emergence of a new field of celestial investigation that incorporated the temporal parameter into the realm of fixed stars. This began with the crisis of the immutability and otherness of the sphere of fixed stars postulated by the Aristotelians, triggered by the 1572 supernova. A century after the celestial novelties introduced by Tycho Brahe, Cassini and his associates revived interest in transient phenomena alongside that in the objects of the Solar System, linking up with the Northern European tradition renewed by Hevelius and Bullialdus, and relaunching their investigations on Mira Ceti and the so-called Nova Cygni.
Cassini's contributions to the study of novae and variable stars, along with those of his collaborators and correspondents, remain partially obscured due to the fragmentary nature of the research and the lack of monographs on the subject. These contributions can only be reconstructed through the study of various sources, including chapters of more general works, manuscripts, letters, short academic reports, and rare iconographic evidence.
Here, I present an overview of these contributions to the emerging astronomy of transient phenomena by Cassini, Montanari and Maraldi, which overlapped with the study of comets, meteors, parhelia and zodiacal light at that time. These contributions enriched the radical renewal of astronomy and laid the groundwork for a novel perspective on the stellar universe that resonates today in the successful field of transient astrophysics.

Author

• Giangiacomo Gandolfi, Astronomical and Copernican Museum in Rome, National Institute for Astrophysics (INAF), Astronomical Observatory of Rome