Cart du Ciel Telescope

By the 1930s, the Carte du Ciel program had already been underway for forty years, and yet a number of plates were still required to complete the coverage of the Vatican zone of the sky. (In fact, the final plates for this project were only taken in 1953.) But with the growing light pollution around Rome, it was soon realized that this instrument needed to be moved to Castel Gandolfo. 

Pope Pius XI approved the move; in 1938, during his last walk before returning to Rome from his summer stay at Castel Gandolfo, he looked around the gardens of the Villa Barberini for a suitable place to put it. But it was only in 1942 that his successor, Pope Pius XII, was able to move the telescope, this even despite the fact that the war had already begun. At that time, the building was limited to the dome where the Carte du Ciel telescope was housed.