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Papal telescopes: Heavens above

Jesuit Fr Gabriele Gionti, a Vatican astronomer, with a 1935 Zeiss telescope (CNS)

The Vatican Observatory is being opened up to the public

When people ask why the Vatican has an observatory, one Jesuit priest says it’s because it cannot afford a particle accelerator.

This nerdy quip by the Vatican Observatory’s vice director, Jesuit Fr Paul Mueller, has become his signature response to those who are surprised to discover that popes have collected telescopes.

Eleven Jesuit astronomers live, work and pray together at two sites: one is in Arizona, at the modern Mount Graham International Observatory, and the other is at their historic headquarters on the grounds of the papal summer villa in Castel Gandolfo near Rome.

Fr Mueller, a US priest who has degrees in physics, history, philosophy and theology, and a doctorate in the history and philosophy of science, says: “Science is part of our life; for us there is no conflict, no tension.”

He spoke while giving reporters a tour of the observatory’s facilities at the papal villa. Four observatory domes and telescopes are housed in two buildings ­– one being the papal residence itself, with a stunning view of Lake Albano, and the other a newly refurbished building in the wooded gardens.

The latter facility houses the Carte du Ciel (Celestial Map) telescope from 1891, a Schmidt telescope from 1957 and a new exhibit showcasing a number of historical scientific instruments, artifacts and meteorites from the observatory’s collections.

The plan is to open the space to the public starting next summer with visits organised by the Vatican Museums.

Fr Mueller said one idea would be to have groups tour the villa’s garden, have dinner and then visit one of the observatory domes for a night of stargazing. The Vatican Museums already organise special tours of the papal villa and gardens at Castel Gandolfo. Fr Mueller said the tour would help to make the historical treasures and achievements of the Vatican Observatory more visible.

The observatory traces its origins back to an observational tower erected at the Vatican by Pope Gregory XIII in 1578 in preparation for reforming the Western calendar. Over time, a number of posts for celestial observation were set up along the Vatican walls and elsewhere in Rome, such as atop the Church of St Ignatius where Jesuit Fr Angelo Secchi – the father of astrophysics – conducted much of his work.

Pope Leo XIII formally established the Vatican Observatory – placed on a hillside behind the dome of St Peter’s Basilica – in 1891 as a visible sign of the Church’s centuries-old support for science.

The pope’s main observatory, by now entrusted to the Jesuits, was eventually moved to Castel Gandolfo in 1935. Two observational domes were built on top of the pope’s summer villa to house two Zeiss telescopes purchased that year.

The Carte du Ciel telescope – what Fr Mueller calls “the jewel” of the observatory – was moved in 1942 from the Leonine Tower in Vatican City to the papal villa and, in 1957, it was joined by a Schmidt wide-angle telescope that Pope Pius XII purchased with his own money as a gift to the observatory, according to astronomer Fr Gabriele Gionti.

The Jesuit observatory staff set up a second research centre in Tucson, Arizona, in 1981 after Italian skies became too bright for night-time observation. Twelve years later, in collaboration with the state’s Steward Observatory, they completed the construction of the Vatican Advanced Technology Telescope on Mount Graham, considered one of the best astronomical sites in the continental United States.

Visitors who participate in next year’s sky-watching tour at the papal gardens are expected to use the Carte du Ciel telescope. It was purchased after an Italian astronomer, Fr Francesco Denza, persuaded Pope Leo in the late 1800s to let the Holy See take part in an international survey of the night sky.

The Vatican was one of some 18 observatories around the world that spent the next few decades taking thousands of glass-plate photographs and cataloguing data for the “Carte du Ciel” project. Sisters Emilia Ponzoni, Regina Colombo, Concetta Finardi and Luigia Panceri, of Sisters of the Holy Child Mary, helped map nearly half a million stars for the Vatican’s assigned slice of the sky.

Claudio Costa, a space systems consultant engineer, oversaw the telescope’s recent restoration. He was the last person to use the historic telescope before it fell into disuse in the 1980s and he was the first to use it after restorers got it fully functioning again.

Soon, the staff hope it will be the public’s turn to peek through this piece of history and view the heavens in a new way.

“When we use the telescopes to examine the heavens, that’s a kind of worship,” Fr Mueller said.

Science, he said, is searching for the truth, which exists in “two books: the book of Scripture and the book of nature”.

While people may struggle to make sense of what they see, in the end, the priest said, “The truth is one, [the books] cannot disagree because God is the author of both books.”