Baldassarre Capra

Baldassarre Capra (Milan, 1580 − Milan, 8 May 1626) was an Italian scientist who disputed Galileo Galilei's claim to priority of the discovery of Kepler's Supernova and also claimed to have invented the proportional compass, accusing Galileo of plagiarism.

Early life The son of count Marco Aurelio Capra and Ippolita Dalla Croce, Baldassarre came from a family of the ancient nobility but with reduced circumstances. His father was an amateur doctor, and in 1594 he moved to Padua with his son so that he could study medicine, astronomy and mathematics. To support them, Marco Aurelio gave fencing lessons. One of his students was Galileo himself, introduced by their mutual acquaintance Giacomo Alvise Cornaro.

Kepler's Supernova In Padua, Capra met Simon Mayr, an astronomer who was a pupil of Tycho Brahe, with whom he studied mathematics. On 10 October 1604, together with Mayr, Capra observed a new star (now known as Kepler's supernova) which had been first seen by the friar Ilario Altobelli, who had written to Galileo about his important discovery.

In three public lectures, Galileo used the discovery of the new star to challenge the ideas of the Peripatetic philosophers of Padua, who held the Aristotelian view that the sphere of the stars was unchangeable. Capra was offended by Galileo's failure to acknowledge him as the person who had discovered the star, and, encouraged by Mayr, in 1605 he published a pamphlet attacking Galileo's position, entitled Consideratione astronomica circa la nova et portentosa Stella che nell'anno 1604 a dì 10 ottobre apparse.

Galileo did not respond to this provocation, but he scribbled marginal notes in his copy with terms such as "bue" ("ox") and "coglione" ("balls"), deriding him for his ignorance of both Italian and Latin. Then, concealing his identity behind the pseudonym 'Cecco di Ronchitti', he responded to Antonio Lorenzini and his pamphlet Discorso intorno alla Nuova Stella (Padua, 1605) in a caustic pamphlet entitled Dialogo de Cecco di Ronchitti da Bruzene in perpuosito de la stella Nuova, written in the ancient dialect of Padua (called "dialetto pavano").

Plagiarism accusation against Galileo Capra's second confrontation with Galileo was sufficiently serious for Galileo to decide he needed to confront it openly. In 1602, Capra and his father had asked Galileo to let them observe how his proportional compass worked – although Galileo had not invented the instrument, he had made it much easier to use and had devised new applications for it. In 1605, the Capras had borrowed a Galilean compass from their friend Giacomo Alvise Cornaro and spent time at the workshop of Marc'Antonio Mazzoleni, the craftsman who made Galileo's instruments, learning how the compass was made. Galileo, who had successfully defended himself against a previous charge of plagiarism in 1602, could not afford to take Capra's claims lightly. He therefore asked for the matter to be adjudicated by the university rectors. After the hearing, Capra left Padua and returned to Milan where he continued to teach the use of the compass. His disgrace was apparently not forgotten, as in 1620 he was refused admission into the city's College of Medicine due to the efforts of Ludovico Settala, who energetically opposed him because of his behavior toward Galileo.