Donati, Giovanni Battista (1826–1873)
Italian astronomer who carried out early spectroscopic studies of the Sun
and stars and was the first to obtain and analyze the spectrum of a comet,
concluding that comets are, at least in part, gaseous. Between 1854 and
1864 he discovered six new comets, the brightest of which, found in 1858,
became known as Donati's Comet. His spectroscopic
observations of the 1864 comet contained three prominent lines which Donati
named alpha, beta, and gamma. These same lines were seen in an 1866 comet
by Angelo Secchi, and shown by William Huggins
in 1868 to be due to the presence of carbon.
After graduating from the university in his native city of Pisa, Donati
joined the staff of the Florence Observatory in 1852 and was appointed director
in 1864. He died from bubonic plague.