According to Localcollegeexplorer, the new Vatican Observatory of Castelgandolfo, directed by the Dutch Jesuit J. Stein, was inaugurated by Pius xi in 1935. Two domes were erected on the Papal Palace for two new instruments built by Zeiss: a visual telescope for direct observation of the stars and a double astrograph for photography. A spectrochemistry laboratory for the analysis of meteorites was founded next to the Observatory. In 1942 the astrograph of the Carta del Cielo was also transported from Rome and installed in the gardens of the Villa Pontificia and in 1957 a new large-field astrograph of the Schmidt type was installed next to it.
With the death of Cardinal P. Maffi (1931) the figure of the president of the Specola had ceased but, with the re-foundation in Castelgandolfo, Pius xi established that this, for the administrative part, constituted a direction of the Governorate and that its management was entrusted to the Society of Jesus. The community of Jesuits assigned to the Specola (10 in 1995) still represents the only example of a scientific research group directly dependent on the Holy See.
Among the main activities we mention: the publication of the last two volumes of the Atlas Stellarum Variabilium by p. JG Hagen (1941); the continuation and completion of the photographs for the Carta del Cielo (1955); the classification of a large number of variable stars, known as Vatican Variables. In 1946, a comet was discovered, called Timmers, named after the Dutch Jesuit who first noticed it on the photographic plate. From p. D. O’Connell, who succeeded Fr. Stein in 1952 is named after an effect he discovered in some eclipse variables. O’Connell himself, who for several years was also president of the Pontifical Academy of Sciences, made an original study on the meteorological phenomenon of the ” green ray ”, first publishing color photographs taken by his collaborator K. Treusch. Main research topics were: interstellar matter; distribution of the stars of the different spectral types; stars with Ha emission lines; spectral classification criteria and brightness criteria; proper motions; position and photometry of stars in open clusters; carbon stars; metallicity of stellar atmospheres; polarization of the light emitted by celestial objects; dark galactic clouds; compact magnetic double stars. At the beginning of the seventies, having to look for a more suitable site for the Schmidt in Italy due to the increased pollution from artificial light, a research was carried out which led to the publication of a Photometric map of artificial lighting for the whole Italian territory.
The Spectrochemistry Laboratory, active until 1976, gained a lot of fame among specialists both with the production of eight atlases of atomic and molecular spectra, and with the foundation of the Spectrochimica Acta magazine . In 1973, a fragment of lunar rock was added to the collection of meteorites, a gift from the President of the United States, R. Nixon, to Pope Paul VI.
Starting in the 1980s, due to the excessive brightness of the night sky in Castelgandolfo, the Specola opened a branch office in Tucson (Arizona) in the United States. The close collaboration with the Steward Observatory of the University of Arizona and the Vatican Observatory Foundation, born out of the generosity of some Catholics in the United States, has allowed the Specola to have, since 1995, a new technology telescope with mirror. of 1.83 m in diameter, installed on Mount Graham at about 3200 m in height. The astronomers of the Specola therefore spend a good part of the year in Tucson for observations and research, while in Castelgandolfo the headquarters of the management, the library, the calculators and the museum remain. Here scientists from the Specola and guest scientists carry out research on the observed data, theoretical and historical studies, and in the summer months study conferences and astronomy schools are organized. Also noteworthy is the noteworthy publishing activity concerning, in addition to specific themes of astronomy, also historical subjects, such as those relating to the Galilean story, as well as to science-faith relations. These initiatives and publications demonstrate Leo’s eminently apologetic accentxiii the mission entrusted to the Observatory at the time of re-foundation, after more than a century, in accordance with the new prospects opened up by Vatican II, has clearly shifted to that of dialogue between the worlds of science and faith.
