Given the enormous interest – we can safely say ‘mania’ – for today’s rare total solar eclipse in parts of the United States, I thought you might be interested to know that, among the millions who will be watching the 2017 eclipse will be a good number of Vatican astronomers – the Jesuits who staff and run the Vatican Observatory, also known as the Specola. They will be watching from Castelgandolfo, from Tucson, Arizona and probably any place that has a good telescope (or ultra safe eyewear).

American Brother Guy Consolmagno, SJ, director of the Vatican Observatory since 2015, will be watching events from Hopkinsville, Kentucky, where he is a guest of Sts. Peter and Paul parish.

I’ve been to the Specola at Castelgandolfo a number of times and, just for fun and a news story, I’ve attended a few of the VOSS (Vatican Observatory Summer School) summer courses there. I only spent one day on those occasions, listening to talks, sharing picnic lunches with students on the terraces of the papal palace at Castelgandolfo and, one day I even did well in a pop quiz!

I’ve known Brother Guy for a number of years and have interviewed him on several occasions for Vatican Insider. We are trying to coordinate our schedules so that I can visit the fairly new location of the Specola offices, classrooms and museum. The Vatican telescopes, however, remain at the original papal palace.

And two years ago I had a serendipitous encounter with Vatican astronomers in Hawaii!

At the start of my 2015 vacation, on my flight to Honolulu from Los Angeles, I was seated next to David Ciardi, an astronomer from Caltech University. He told me that the IAU – International Astronomical Union – was holding its 29th General Assembly in Honolulu. This was a two-week long meeting that brought together over 2,500 astronomers from 75 countries around the world – including Vatican City State! Bro. Guy was kind enough to send me the names of the Jesuit astronomers who were at this meeting and I was able to interview Fr. Christ Corbally for Vatican Insider.

Sources for the story below include visits to the Specola, conversations with Brother Guy and others and the observatory website. The photos are from my visits to the papal palace and observatory, except for two pictures from the observatory website that I identify as such.

I love the title of one article on the observatory website: “For Heavens Sake: Papal Astronomers Promote Harmony of Science, Faith.”


When Popes spent the summer period at the Apostolic Palace at Castelgandolfo, one of the many hill towns or “castelli romani” southeast of Rome, they enjoyed cooler air, a slower ace of life and a view of lovely and placid Lake Albano, which fills an old volcanic crater, and the beautiful sprawling hills which surround it.

The palace at Castelgandolfo also offers Popes another, more spectacular view, should they so wish – a view of the universe through the telescopes of the twin observatory towers atop the pontifical residence.

The Specola, as the Vatican Observatory is also called, is not only one of the most highly respected observatories in the world but is actually one of the oldest astronomical institutes, dating back to 1582 when Pope Gregory XIII formed a committee to look at the scientific data and ramifications involved in a reform of the calendar. One of the committee members, Fr. Christoph Clavius, a Jesuit mathematician from the Roman College, wrote books favoring this reform and, with some of his brother Jesuits interested in astronomy, confirmed studies done by Galileo. In fact, his name is used in the Vatican Observatory website:

Astronomy for centuries was considered “the queen of sciences.” As Fr. Clavius wrote in 1570: “Astronomy uses geometrical and arithmetic demonstrations which, in agreement with the opinion of all philosophers, arrives at the first degree of certitude.”

Astronomy thus became a subject of great interest to the papacy and, in ensuing centuries, Roman Pontiffs founded three observatories: that of the Roman College, the observatory of Capitoline Hill and the Specola Vaticana in the Tower of the Winds in the Vatican. Telescopes in the Vatican occupied different locations over the years. In 1935 the Specola was moved to Castelgandolfo because the light emanating from the city of Rome was too strong to allow for accurate observation and research from within the city.

For the same reasons a new telescope was built in Arizona, in the United States in 1993. The Vatican’s state of the art VATT – Vatican Advanced Technology Telescope – is located on Emerald Peak at an altitude of 3,200 meters in the Mt. Graham mountain chain, northeast of Tucson, Arizona. The telescope became operative in 1993 when the Vatican, in collaboration with Steward Observatory at the University of Arizona in Tucson, used new technology in making the telescopic mirror, thus entering the era of the advanced technology telescopes. The telescope was made by using a rotating furnace, which shortened the construction time and offered a mirror that was lighter in weight than its predecessors. This method of making mirrors has been used with great success ever since.

Pope Pius XI, in a speech on September 29, 1935 at the new observatory at Castelgandolfo gave it a motto – Deum Creatorum Venite Adoremus (Come let us adore God the Creator) – and said he rejoiced in being present at “the inauguration of this new, and might we say, improved ‘Specola Vaticana’ in this our residence at Castelgandolfo.” He also said: “It is quite well known that the Supreme Roman Pontiffs have for many centuries needed astronomy and have called on it to help in the placement of holy temples and especially in the calculation of the date of Easter.”

Pope Leo XIII is actually credited with “re-founding” the Vatican Specola over four decades earlier. In July 1890 he approved the Directives for the Specola Vaticana and, on March 14, 1891, promulgated the Motu proprio Ut mysticam (As a mystery), writing that he wished to refute those who charged the Church with being “obscurantist and closed to scientific progress.” Leo XIII said he intended to reinstitute the Specola so that “everyone might see clearly that the Church and her pastors are not opposed to true and solid science, whether divine or human, but that they embrace it, encourage it, and promote it with the fullest possible dedication. …  And we desire that the Specola be considered at the same level as the other Pontifical Institutes founded to promote the sciences.”

Successive Roman Pontiffs have always supported the Vatican Observatory and its directors, who have always been priests-scientists and, for over 100 years, Jesuits. In fact, given the importance of their work, 35 lunar craters bear the names of Jesuits astronomers. The current director is American Brother Guy Consolmagno, a native of Detroit who spends part of each year at the Castelgandolfo headquarters, part of the year teaching astrophysics and doing research in Tucson and some time each year traveling and lecturing. He was named to this post by Pope Francis in 2015.

Popes, and in a special way John Paul II, have not only supported the Specola but have written and spoken extensively, on the science-faith dialogue.

In an October 31, 1992 address to the Pontifical Academy of Sciences, Pope John Paul called the case of Galileo Galilei, condemned in the 17th century for his heliocentric theory, a “case of tragic mutual incomprehension which now belongs to the past.” The Pope was addressing the academy on a report given by Cardinal Paul Poupard on the results of 11 years of work by a special commission established by John Paul in July 1981 to study and definitively resolve the Galileo case. The year 1992 marked the 350th anniversary of Galileo’s death.

Saying the Galileo case was “shelved,” John Paul II added: “The underlying problems of this case concern both the nature of science and the message of faith.” In Galileo’s time, he declared, “the majority of theologians did not recognize the distinction between Sacred Scripture and its interpretation and this led them to transpose into the realm of the doctrine of the faith a question which in fact pertained to scientific investigation.”

Though the main body of astronomical observations and research is done today in Arizona, the Apostolic Palace at Castelgandolfo remains the headquarters of the Vatican Observatory.

Before it moved to a new site in the papal gardens in 2009, the observatory staff worked out of the top floors of the Apostolic Palace – right above the private rooms of the papal residence. In 2003, the final days of the 2003 astronomy summer school sessions in the Apostolic Palace coincided with the first days of Pope John Paul’s vacation at Castelgandolfo.  Never had such a group been at the papal residence while the Holy Father was also there, and the 26 students in attendance expressed “awe” at the thought of “studying in the Pope’s home.” Fr. George Coyne, the then director of the Specola, called this a “first.”

In 2009 the Specola moved from the summer papal palace to new headquarters in the papal Gardens at Castelgandfolo. A former convent, the building was specifically remodeled with the needs of the Specola in mind, and space is divided into three areas: 1. The ground floor is public area and workspace: offices, libraries, labs and a small museum of historic scientific equipment and a valuable meteorite collection, 2. Area used primarily by the Vatican Observatory Summer Schools, and 3. Upstairs is the living area for the Jesuit astronomers, including the community chapel.

Among precious objects in the museum is a valuable mineral collection that includes pieces going back 4.5 billion years, a piece of moon rock brought back to Earth in 1972 by the Apollo XVII mission, and fragments of meteorites from Mars.

Though the interior is completely new, the building itself dates back to 1631, the same year that Princess Caterina Savelli of Albano built a convent for the Clarisse Sisters (also known as the “Poor Clares”) on this site. During the Napoleonic wars (sometime between 1791 and 1810) this building was sacked by French troops. With the unification of Italy in 1870, the convent was closed and the sisters moved into the palace in Castelgandolfo, along with a community of Basilian nuns who had been exiled from the part of Poland then controlled by Russia.

In 1929, with the signing of the Lateran Treaty, the two groups of sisters were able to move back into their old quarters, now incorporated within the gardens. The building again was subject to the ravages of warfare in 1944. Following the invasion of Anzio by the Allies and their slow march up the coast to Rome, the building was hit twice, on February 1 and February 10, 1944. After the war, Pope Pius XII approved the reconstruction of the convent.

The building was also damaged during an earthquake in 1989; repairs and restructuring of the building were completed in 1998. In 2007, work began to completely restructure the end of the building that belonged to the Basilica sisters, who had left the premises, to match the needs of the astronomers. After two years of extensive work, the new Specola headquarters was dedicated by Pope Benedict XVI on September 16, 2009. The Clarisse sisters continue their prayer and work in the northwestern end of the building. (photo:

The observatory holds summer school sessions every two years, Known as VOSS (Vatican Observatory Summer School), the next scheduled session in June 4 –29, 2018. As the website says: “The VOSS 2018 will train the next generation of researchers on the marvels of big data, time domain astrophysics, and variability surveys.” Among the main themes: Theory of stellar pulsation and evolution: pulsation and evolutionary properties of radial variables, Stellar kinematics: radial velocities and proper motions.

Pope Francis, on Friday, May 12, 2017 greeted participants in a conference organized by the Vatican Observatory entitled “Black Holes, Gravitational Waves and Space-Time Singularities. The conference took place at the Observatory at Castelgandolfo in the Roman Hills.

“I am deeply appreciative of your work,” said Francis, “and I encourage you to persevere in your search for truth.  For we ought never to fear truth, nor become trapped in our own preconceived ideas, but welcome new scientific discoveries with an attitude of humility.  As we journey towards the frontiers of human knowledge, it is indeed possible to have an authentic experience of the Lord, one which is capable of filling our hearts.”


Brother Guy Consolmagno SJ is Director of the the Vatican Observatory and President of the Vatican Observatory Foundation. A native of Detroit, Michigan, he earned undergraduate and masters’ degrees from MIT, and a Ph. D. in Planetary Science from the University of Arizona; he was a postdoctoral research fellow at Harvard and MIT, served in the US Peace Corps (Kenya), and taught university physics at Lafayette College before entering the Jesuits in 1989. (Photo:

At the Vatican Observatory since 1993, his research explores connections between meteorites, asteroids, and the evolution of small solar system bodies, observing Kuiper Belt comets with the Vatican’s 1.8 meter telescope in Arizona, and applying his measure of meteorite physical properties to understanding asteroid origins and structure. Along with more than 200 scientific publications, he is the author of a number of popular books including Turn Left at Orion (with Dan Davis), and most recently Would You Baptize an Extraterrestial? (with Father Paul Mueller, SJ).  He also has hosted science programs for BBC Radio 4, been interviewed in numerous documentary films, appeared on The Colbert Report, and for more than ten years he has written a monthly science column for the British Catholic magazine, The Tablet.

Dr. Consolmagno’s work has taken him to every continent on Earth; for example, in 1996 he spent six weeks collecting meteorites with a NASA team on the blue ice regions of East Antarctica. He has served on the governing boards of the Meteoritical Society; the American Astronomical Society Division for Planetary Sciences (of which he was chair in 2006-2007); and IAU Commission 16 (Planets and Satellites). In 2000, the small bodies nomenclature committee of the IAU named an asteroid, 4597 Consolmagno, in recognition of his work. In 2014 he received the Carl Sagan Medal from the American Astronomical Society Division for Planetary Sciences for excellence in public communication in planetary sciences.