Angelo Secchi, Italian astronomer, c 1860s.

Angelo Secchi (1818-1878), Italian astronomer, was well known for his observations of the Sun. At the solar eclipse of 1860 observed in Spain, Secchi succeeded in photographing the prominences and the corona. Later, he initiated the field of spectral clasification. After using an objective prism to observe several thousand stellar spectra, he divided them into three types - white, yellow and red - which corresponded roughly to their temperatures. Secchi became widely known after the publication of his book 'Le Soleil' (1875).