an Italian Jesuit, astronomer, and physicist. As an astronomer he may have been the first to see the belts on the planet Jupiter (on May 17, 1630), and reported spots on Mars in 1640. His Optica philosophia experimentis et ratione a fundamentis constituta, published in 1652–56, described his 1616 experiments using a curved mirror instead of a lens as a telescope objective, which may be the earliest known description of a reflecting telescope.
