Vatican Corner 01-05-2020

After the time of Galileo, when the Catholic Church wrongly condemned him for his astronomical proof that the sun and not the earth was the center of the solar system, the Church developed a keen interest in astronomy. The papacy founded three early observatories: Roman College (1774-1878) , the Capitol (1827-1870), and Specola Vaticanna 1789-1821). Father Angelo Secchi doing research at the Roman College had a breakthrough in the mid-nineteenth century. He was the first to classify stars by their spectra, the color of light that stars emit. At the end of the 19th century two things happened. The unification of Italy meant that the Holy See was desperate to still be recognized as an independent country. Having a national observatory was a sign of nationhood. Also the idea had developed that church and science might be at battle with each other, and the pope wanted a way to show that the Church supported science. Pope Leo XIII set up another small observatory behind Saint Peter’s Basilica. In 1910, Pope Pius X gave that observatory a new and larger space in the Vatican Gardens. From 1914 to 1928 the observatory along with 17 others around the world contributed to the Astrographic Catalogue, an ambitious project to map all of the sky. The Vatican’s work published the brightness and position of 481,215 stars. By the 1930s, light pollution from the city of Rome prevented the study of fainter stars and galaxies, so Pope Pius XI relocated the observatory to Castel Gandolfo, the papal summer retreat about 16 miles southeast of Rome overlooking Lake Albano. The Jesuits were put in charge of the observatory and three new telescopes were constructed along with an astrophysical laboratory for spectral analysis of distant celestial bodies. Research programs began on Cepheid variables, stars that pulsate radially, varying in both diameter and temperature. Those type stars are used to determine distance measurements. A Schmidt wide-angle telescope was installed in 1957 allowed more work on the classification of star. The telescopes at Castel Gandolfo are rarely used anymore for astronomical research and instead are visited by touring groups and summer-school students. All serious astronomy is now performed using other telescopes around the world, mainly those in Arizona. To be continued…