This site has been archived for historical purposes. These pages are no longer being updated.

Angelo Secchi, S.J.
(1818 ­ 1878)
the Father of Astrophysics

Angelo Secchi, S.J.

Angelo Secchi, S.J. was born in Reggio, Italy and died in Rome. He was a physicist and mathematician with remarkable ability and passion for astronomy. Angelo worked in stellar spectroscopy, made the first systematic spectroscopic survey of the heavens, pioneered in classifying stars by their four spectral types, studied sunspots, solar prominences, photographed solar corona during the eclipse in 1860, invented the heliospectroscope, star spectroscope, telespectroscope and meteorograph. He also studied double stars, weather forecasting and terrestrial magnetism. He became director of the Vatican Observatory at the age of 32 and dedicated himself energetically to the task. Sabino Maffeo S.J. tells the story of his tenure at the Vatican Observatory. (See Maffeo S.J. Sabino, In the Service of the Popes Translation by George V. Coyne, S.J. Pg. 13-15).

A 1979 series of Vatican stamps commemorate Angelo and the three instruments he perfected: The meteorgraph, the stellar spectroscope and the telescope.

He acquired an equatorial telescope of Merz with an aperture of 24 cm and a focal length of 435 cm, an excellent instrument for those times. Angelo decided to transfer the observatory to the top of the Church of St. Ignatius, a perfect foundation for an observatory, because the Church had been originally designed to support a dome 80 meters high and 17 meters wide. This Pontifical Observatory, famous for the discoveries of Father Secchi, was certainly more known to many generations of Romans for the simple, practical, daily service it offered them. It gave them the exact time of day.

Angelo Secchi's observatory on the roof of St. Ignatius Church In Rome

Angelo Secchi was particularly attracted to astrophysics, a courageous choice in a time when this field was little developed. Nevertheless, he did not neglect other areas of astronomy. He also had regular teaching assignments in astronomy and physics at the Gregorian University, and had many other chores t keep him busy. He observed double stars, nebulae, planets and comets. He discovered three comets in the years 1852-1853. He studied terrestrial magnetism and meteorology; he was in charge of setting up a new triangulation base on the Via Appia; he went to various cities to repair or install new water systems; he established lighthouses in the ports of the Papal States; and he even had to look after the positioning of solar clocks. In addition to his great works on the sun, on the fixed stars, and on the unity of physical forces, he published about 730 small papers in various scientific journals. Angelo had a particular interest in the sun: its innumerable facets attracted his attention right up to the time of his death. He kept a daily record of the number of sunspots, and of their appearance and movement; at the eyepiece of his telescope, he drew pictures of the most interesting spots. Using a new technique for observing solar prominences outside of eclipse, Angelo found the connection between prominences and sunspots. His magnificent drawings of the huge red hydrogen jets extending from the solar surface in stupendous and ever changing shapes, have become classics of astronomical literature.

After that he pointed his spectroscope to the stars. Following the example of Fraunhofer and Respighi, he was the first to use a round prism in front of the lens of the Cauchoix refractor. In this way he observed more than 4,000 stars and came to a discovery whose importance not even he could understand. Although there were many differences among the spectra of the individual stars, he also found many similarities, and, using these as a criterion, he identified four classes of spectra. Because of this discovery Angelo is considered the father of the spectral classification of stars, a tool which has proven to be very powerful for research on the origins and structure of stellar systems.

After the occupation of Rome in 1870, the Roman College was declared state property. When the Italian Government threatened to occupy also the observatory, Angelo Secchi made a serious protest threatening to accept one of the positions which had been offered to him in England, France and the United States. But this world-renowned astronomer was left in peace and for the moment the Observatory and its staff remained under the Holy See. The great bronze inscription over the entrance still remained in place: Osservatorio Rontificio.

The reprieve did not last long. After a long and painful sickness Angelo Secchi died on 26 February 1878 and his successor, was removed from the Observatory in the following year. So this last of the papal observatories, which had weathered so many difficult times without receiving the recognition due to it, came to an end. Its name was changed to: Regio Osservatorio al Collegio Romano (Royal Observatory at the Roman College). In 1923 even this last bit was terminated.


Archivum Historicum Societatis Iesu ( AHSI ) Rome: Institutum Historicum
Bangert, William A History of the Society of Jesus. St. Louis: St. Louis Institute, 1972uis, 1810
Gillispie, Charles. C. ed., Dictionary of Scientific biography. 16 vols. New York: Charles Scribner and Sons, 1970
Maffeo S.J. Sabino, In the Service of the Popes Translation by George V. Coyne, S.J. Pg 13-15
Sommervogel, Carolus Bibliothèque de la compagnie de Jésus. 12 volumes. Bruxelles: Société Belge de Libraire, 1890-1960

Return to Home Page