Used with
permission of Maiken Naylor, University at Buffalo, Buffalo, NY, USA,
http://ublib.buffalo.edu/libraries/units/sel/exhibits/stamps
The Jesuit Pietro Secchi (1818-1878), an Italian astronomer, was the first to apply spectroscopy and photography to astronomy, taking spectra of the stars and photographs of the sun during eclipses. His compilation of stellar spectra led to the classification of the well-known spectral types of stars. As longtime director of the Gregorian University Observatory in Rome, he introduced the newest equipment for his studies.