Date: September 30, 2009

Title: The Delight of Stars


Podcaster: Brother Guy Consolmagno

Organization: The Vatican Observatory

The music “Ocean Blue” was written and performed by Warren Raiti

Description: The Vatican Observatory is one of the oldest astronomical institutions in the world, dating from the reform of the calendar in 1582 — when Galileo himself was just a teenager! We’ve been around in our present form since 1891, a group of a dozen Jesuits from four continents all united by a love of the sky. Here’s who we are, and what we’re doing… both in our regular work, and special this year for the IYA.

Bio: Brother Guy Consolmagno SJ is a planetary scientist and Curator of Meteorites at the Vatican Observatory. He earned two degrees from MIT and a Ph. D. in Planetary Science from the University of Arizona, was a postdoctoral fellow at the Harvard/Smithsonian Center for Astrophysics and MIT, served in the US Peace Corps, and taught physics, before entering the Jesuits in 1989. At the Vatican Observatory since 1993, his research explores the physical nature of meteorites, asteroids, and dwarf planets. He is also a co-author (with Dan Davis) of the astronomy best-seller Turn Left at Orion.

Today’s sponsor: This episode of “365 Days of Astronomy” is sponsored by Joseph Brimbacombe.


Hi! I’m Brother Guy Consolmagno, an astronomer at the Vatican Observatory, one of the oldest astronomical observatories in the world. I am speaking today from the headquarters of the Observatory, in the gardens of the Pope’s summer home in Castel Gandolfo, in the hills outside Rome.

The Vatican Observatory has been guests of the Popes here since 1935. Before that, we actually had telescopes on the walls of the Vatican itself, in the center of Rome. Eventually, light pollution made that impractical, of course; and in the 1980s the city lights had reached Castel Gandolfo as well, so nowadays the Vatican Observatory also has a modern telescope on a desert mountaintop in southern Arizona.

But… Vatican Observatory? What is the Vatican doing with an observatory?

Well, this is the International Year of Astronomy, celebrating the 400th anniversary of the night Galileo first pointed his telescope to the sky. And the Vatican is a national participant of the organizations who are sponsoring the IYA, like UNESCO and the International Astronomical Union; and so astronomers at the Vatican Observatory have been active participants in the IYA activities. After all, Galileo was an Italian, and a Catholic; we’re proud of the local boy who made good. (And he wouldn’t be the first Italian, or the first Catholic, to get into trouble with the authorities.) For the IYA we’re co-sponsoring meetings on topics from astrobiology to astronomy and culture, we’ve collaborated on planetarium shows and films like the “400 Years of the Telescope”; I’m part of the Cosmic Diary blog; and we’ve just published a popular coffee-table book on astronomy and the Vatican, called The Heavens Proclaim.

At the beginning of this podcast, I introduced myself as “Brother”; in fact, I am a member of the Society of Jesus – the religious order commonly called the Jesuits. Most of us at the Vatican Observatory are Jesuit priests and brothers. And even before Galileo ground his first lens, Jesuits have had a long tradition of working in astronomy. In 1582, Fr. Christoph Clavius helped Pope Gregory XIII reform the calendar, and then he wrote the book to explain that reform to the rest of the world. He also wrote a letter of recommendation for the young Galileo when he was looking for a teaching job; and late in his life he got to look through Galileo’s telescope and see the moons of Jupiter for himself.

And what about Galileo? A ten minute podcast isn’t long enough to do that topic justice, of course. Go to the library and read a book; better yet, read several books. There must be a hundred books about Galileo out there; and none of them agree about exactly why he got into trouble. Certainly the Church screwed up; but exactly what it was they did wrong varies from story to story, depending on who’s telling the story. If nothing else, that should tell you that the truth is way more complicated than you may have been led to believe.

Meanwhile, other Jesuits at the Roman College during the time of Galileo devised the first reflecting telescope, inferred the wave nature of light, and mapped the Moon and named its craters, devising the system for lunar nomenclature we still use to this day. Incidentally, they named the most prominent crater on the Moon, “Copernicus.”

A quarter of the European observatories observing the transits of Venus in the eighteenth century were run by Jesuit priests. From 1803 to 1824, Fr. Giuseppe Calandrelli and his collaborators produced eight volumes of Astronomical Tracts detailing their research on the sun, planets, comets, and stellar occultations. The Jesuit priests Etienne Dumouchel and Francesco de Vico were the first to recover Comet Halley in 1835; and in addition, De Vico also determined the orbits of the Saturnian satellites Mimas and Enceladus.

And of course Jesuit missionaries did astronomy all around the world. In China they were the official astronomers of the Emperor for hundreds of years. In the southern hemisphere, Jesuit priests were the first to recognize that Acrux and Alpha Centauri were double stars. Fr. Jean de Fontanay split Acrux in 1685 from the Cape of Good Hope in South Africa; and Fr. Jean Richaud split Alpha Centauri in 1689, while observing a nearby comet from India.

Why were they all doing astronomy?

In the 19th century, Fr. Angelo Secchi put telescopes on the roof of St. Ignatius Church next to the Roman College and discovered dark markings on Mars that he called canali (incidentally, what he saw were real, and quite different from the illusional “canals” that later astronomers thought they were seeing.) His work on the solar corona was so pioneering that today a suite of cameras on NASA spacecraft that study the solar wind are called the “Sun-Earth Connection Coronal and Heliospheric Investigation” package: the acronym spells “Secchi.” And most importantly, Secchi was the first astronomer to classify and sort stars by their spectral colors – work that is the foundation of modern astrophysics.

So, how come Father Secchi was on the roof of the church looking at stars and planets, instead of inside the church praying?

We have priests at the Vatican reforming the calendar, mapping the moon, discovering double stars, recovering comets, inventing the basics of astrophysics. And it’s not just Jesuits. The Belgian diocesan priest, Father George Lemaitre, had two doctorates – one from Leuven and another from MIT – and in the late 1920s, after working with Sir Arthur Eddington in Cambridge, he wrote a paper on cosmology that outlined what has come to be known as the Big Bang theory.

OK, so we have a pretty good history. But why is there a Vatican Observatory today? Who are we, and what are we up to?

We’re a dozen priests and brothers from all over the world… we come from Italy and England, Argentina, the Congo, the United States, and there are younger Jesuits preparing to join us from the Czech Republic and India. We each got our astrophysics training and our degrees from universities all over the world: Cambridge and Oxford, Georgetown and Toronto, Padua and Paris, Arizona and MIT. We have active research programs in cosmology; string theory; galaxies and galactic clusters; stellar spectroscopy. And then there’s meteoritics and planetary sciences, which is my field; it turns out, the Vatican has one of the best meteorite collections in the world.

But what actually are we all about? What does it mean to be an astronomer at the Vatican Observatory today?

It’s not all that different from any other observatory…

It is a week spent in near silence, awake all night on a cold lonely mountaintop under a starlit sky, quietly moving a telescope from star field to star field, typing a few commands into a computer, waiting for the starlight to be gathered into a frozen chip of silicon.

It is looking through a microscope at a thin slice of a meteorite and wondering what part of the asteroid belt could have provided those shocks, melted those minerals.

It is encountering twenty five brilliant young graduate students from around the world, at our summer school in the Pope’s summer home south of Rome, where they gather for a month to learn more about astronomy… and to make those friendships that will be renewed at scientific meetings for the rest of their lives.

It is staring at a computer screen displaying not beautiful color images, but stars as random dots of black and white amidst every flaw on the detector chip, every speck of dust on the filter, the shadow of the moth that happened to fly into the telescope while you were taking the image. You hope that the image of your target object doesn’t also include the light from some faint distant galaxy in the same line of sight. And then you realize that the faint, anonymous, distant galaxy that’s getting in the way of your data is a collection of a hundred billion stars; each star likely surrounded by planets; and even if life is a one in a million chance, that would still mean a hundred thousand places in that little smudge where there could be alien astronomers looking back at you, muttering about that distant smudge of the Milky Way getting in the way of their observations.

It is explaining once again to the hundredth reporter this year, why the Church supports an observatory; why there is nothing new to say about aliens, or the Star of Bethlehem, or the DaVinci Code; why the Galileo story is a whole lot more complicated than the story everybody knows.
It is stepping outside your room late at night, to just look up at the stars.

Why does the Vatican have an observatory? Well… why does anybody have an observatory? I mean… have you looked at the stars lately?

End of podcast:

365 Days of Astronomy
The 365 Days of Astronomy Podcast is produced by the New Media Working Group of the International Year of Astronomy 2009. Audio post-production by Preston Gibson. Bandwidth donated by and wizzard media. Web design by Clockwork Active Media Systems. You may reproduce and distribute this audio for non-commercial purposes. Please consider supporting the podcast with a few dollars (or Euros!). Visit us on the web at or email us at Until tomorrow…goodbye.

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