February 23, 1583 — November 6, 1656
Jean-Baptiste Morin, also known by his Latin pseudonym as Morinus, was a French mathematician, astrologer, and astronomer.
In 1630, Morin was appointed professor of mathematics at the Collège Royal, a post he held until his death.
A firm believer of the idea that the Earth remained fixed in space, Morin is best known for being opponent of Galileo and the latter's ideas. He continued his attacks after the Trial of Galileo. Morin seems to have been a rather contentious figure, as he also attacked Descartes' ideas after meeting the philosopher in 1638. These disputes isolated Morin from the scientific community at large.
Morin believed that improved methods of solving spherical triangles had to be found and that better lunar tables were needed.
Morin attempted to solve the longitude problem. In 1634, he proposed his solution: it was based on measuring absolute time by the position of the Moon relative to the stars. It was a variation of the lunar distance method. Morin added some improvements to this method, such as better scientific instruments and taking lunar parallax into account. Morin did not believe that Gemma Frisius' transporting clock method for calculating out longitude would work. Morin, unfailingly irascible, remarked, "I do not know if the Devil will succeed in making a longitude timekeeper but it is folly for man to try."
A prize was to be awarded, so a committee was set up by Richelieu to evaluate Morin's proposal. Serving on this committee were Étienne Pascal, Claude Mydorge, and Pierre Hérigone. The committee remained in dispute with Morin for the five years after he made his proposal. Morin refused to listen to objections to his proposal, which was considered impractical. In his attempts to convince the committee members, Morin proposed that an observatory be set up in order to provide accurate lunar data.
In 1645, Cardinal Mazarin, Richelieu's successor, awarded Morin a pension of 2,000 livres for his work on the longitude problem.
Morin’s life has been that of trial and tribulation by his own testament.