SECCHI, ANGELO

SECCHI, ANGELO. – Jesuit and astronomer, born at Reggio Emilia on 18 June 1818, died at Rome on 26 February 1876. He entered the Society of Jesus in 1833 and the Collegio Romano in 1835, then temporarily went on to teach mathematics and physics at the Jesuit College in Loreto (1841).

When the Jesuits were expelled from Rome and from the Collegio Romano (1848), during the brief interval of the Roman Republic, S. followed into exile his former teachers at the Collegio Romano, Fr. Francesco De Vico, director of the Observatory of the Collegio Romano, and Fr. G. Pianciani, going first to Stonyhurst in England and then to Georgetown in America. There he became acquainted and formed a close friendship with the famous hydrographer F. M. Maury, whose studies later had a great influence on S. When the Jesuits returned to Rome at the end of 1849, S. was entrusted with the direction of the astronomical observatory of the Collegio Romano. His first concern was to improve the condition of the observatory, which left rather much to be desired; indeed, he built a completely new observatory beside the old one, installing three astronomical instruments of considerable efficiency for those times in a fitting manner on the extremely solid pillars of the cupola then being erected for the church of S. Ignazio in Rome (which for this reason thereafter remained without a cupola). Thanks to S., the new Observatory

(courtesy of V. Brajevic)

SEBENICO, DIOCESE of – Side portal of the cathedral, originating from the pre-existing church (14th century).

acquired great renown in a short time, especially in the field of astrophysics, the new branch of astronomy, of which S. may rightly be regarded as one of the founders. When the new government entered Rome in 1870, it naturally took possession of all public offices, all administrations, and all institutions of higher learning. It found itself facing no small embarrassment with regard to the Observatory of the Collegio Romano—or, more precisely, its director, whose reputation certainly extended far beyond Italy alone. Sensibly, the government, through the special intervention of Q. Sella, M. Minghetti, and A. Scialoia, left S. undisturbed in his observatory, and likewise left the other Jesuits who assisted him there: Fr. Gaspare Stanislao Ferrari and Brother Marchetti.

S.’s activity was immense. In 1852 he located the two fragments of Biela’s comet in the sky. In 1859 he devoted himself to observing Mars, discovering two dark channels (indeed, it is precisely to S. that we owe the name “channels,” later adopted by Schiaparelli and disseminated throughout the world). He then devoted himself to solar physics, carrying out numerous important investigations and discoveries, collected in his work Le soleil (Paris 1875–77, Italian ed. Florence 1884); he observed the two solar eclipses of 1860 in Spain (where he took the first photographs of the solar corona; the famous daguerreotypes are still preserved in the Museum of the Observatory of Monte Mario in Rome) and of 1870 in Sicily. He made numerous and ingenious observations of solar prominences, subsequently initiating, in the Memorie della Società degli spettroscopisti italiani (founded by him and P. Tacchini), the long and uninterrupted series of spectroscopic images of the solar limb (the first in the world), which is currently being continued through international collaboration.

But perhaps his greatest work was carried out in the field of celestial spectroscopy, of which he was one of the few pioneers; more precisely, his principal discovery was that of the spectral types of stars. After the first observations of stellar spectra, S.—taking advantage of Rome’s fine skies and using a good instrument suited to this type of study—examined the spectra of 4,000 stars individually and obtained (1867) a classification consisting of four principal “types,” which was universally accepted and still forms the basis of other, more recent classifications. He also made important discoveries concerning nebulae, in which he found dark masses, the size and structure of the universe, the unity of physical forces, etc. His geodetic works are also famous, including the measurement of the base line on the Via Appia.

Among his works, besides his numerous notes and memoirs, are: Le stelle (Milan 1877); L'unità delle forze fisiche (Rome 1864; reprinted in 2 vols., Milan 1874); Le recenti scoperte astronomiche (Rome 1868).

Le rév. p. S., sa vie, ses observatoires, ses travaux, Paris 1879; J. Poble, P. A. S. Ein Lebens u. Kulturbild., 2nd ed., Cologne 1904 (with a complete bibliography of the works); G. Castellani, Dieci lettere ined. del p. A. S. a sua madre Luigia Belgieri, in Arch. hist. Soc. Jesu, 1 (1932), pp. 85–89; id., Il p. A. S. e le sue missioni, in Cro. Catt., 1933, IV, pp. 606 ff. Lucio Gialanella