Amici, Giovanni Battista (jōvän`nē bät-tēs`tä ämē`chē), 1786–1863, Italian astronomer, mathematician, and naturalist. He became director of the observatory and professor of astronomy at Florence and published papers on various scientific subjects. His most important work was in designing and improving physical and astronomical apparatus, especially the microscope and reflecting telescope. He ground several 10-in. to 12-in. metal mirrors. He invented a combination of three prisms that is still used in spectroscopy and is known as the Amici prism.