A astronomer and
optician who made important improvements in the mirrors of reflecting
telescopes and also developed prisms for use in refracting spectroscopes
(instruments used to separate light into its spectral components).
as professor of mathematics at the University of Modena from 1815 to
1825 and then became astronomer to the Grand Duke of Tuscany and director
of the observatory at the Royal Museum in Florence, where he also lectured
at the museum of natural history. He made major advancements in compound-microscope
design and introduced (1840) the oil-immersion technique, in which the
objective lens is immersed in a drop of oil placed atop the specimen
under observation in order to minimize light aberrations.
is most often associated with improvements in the microscope and reflecting
telescope, but he also put his instruments to good use. His observations
of Jupiter's satellites and certain double stars were highly esteemed.
Using an improved micrometer of his own design, he made accurate measurements
of the polar and equatorial diameters of the Sun. With his improved
compound microscope he made discoveries about the circulation of sap
in plants and the processes of plant reproduction.