Photographs of the total solar eclipse of 1860

Four photographs on sensitive paper, glued on soft cardboard
[Desierto de las Palmas, Spagna, 18 luglio 1860]
280 x 220 mm
Historical archives of INAF-Astronomical Observatory of Rome, Monte Porzio Catone (Rome)

The first attempts of Secchi to photograph a solar eclipse date back to 1851, when he carried out some photographic tests at the Collegio Romano, with unsatisfactory results; during the same eclipse, Julius Berkowski, at the Königsberg observatory, obtained the first daguerretype of the totality phase. Secchi then began photographing the Moon, without abandoning the idea of retrying solar photographs. The right chance occurred in 1860, when he was invited to Spain to observe the total eclipse of the Sun on July 18. Under that circumstance he succeeded in obtaining some images of the totality phase, which were determining to resolve the question about the nature of the solar prominences. The photographs of that phenomenon, here reproduced, have hand annotations written by Secchi, mainly aimed at the marking the position of the observed prominances.

Ileana Chinnici, INAF-Osservatorio Astronomico di Palermo