March 25: Giovanni Battista Amici

Giovanni Battista Amici

March 25, 1786 - April 10, 1863

Giovanni Amici was an Italian astronomer and microscopist who invented the dipleidoscope, an  instrument used to determine true noon.

Amici was born in Modena, Italy. After studying at Bologna, he became professor of mathematics at Modena, and in 1831 was appointed inspector-general of studies in the duchy. A few years later he was chosen director of the observatory at Florence, where he also lectured at the museum of natural history.

His name is best known for the improvements he effected in the mirrors of reflecting telescopes and especially in the construction of the microscope. The Amici prism, a combination of three prisms, is still used in refracting spectroscopy. He was also a diligent and skillful observer, and busied himself not only with astronomical subjects but also with biological studies. 

In astronomy, Amici studied double stars, Jupiter's moons and designed improvements to reflecting telescope mirrors including grinding several 10-inch and 12-inch metal mirrors. With his own micrometer design, Amici made accurate measurements of the polar and equatorial diameters of the Sun. Combining botany interests with innovative advances in compound microscopes, the Italian scientist made important discoveries about the circulation of sap in plants and the processes of plant reproduction, including many details of orchid pollination and seed development.

The Lunar crater Amici is named in his honor.