The Sun in the Church: Cathedrals as Solar Observatories

by J.L. Heilbron

Between 1650 and 1750, four Catholic churches were the best solar observatories in the world. Built to fix an unquestionable date for Easter, they also housed instruments that threw light on the disputed geometry of the solar system, and so, within sight of the altar, subverted Church doctrine about the order of the universe.

A tale of politically canny astronomers and cardinals with a taste for mathematics, "The Sun in the Church" tells how these observatories came to be, how they worked, and what they accomplished. It describes Galileo's political overreaching, his subsequent trial for heresy, and his slow and steady rehabilitation in the eyes of the Catholic Church. And it offers an enlightening perspective on astronomy, Church history, and religious architecture, as well as an analysis of measurements testing the limits of attainable accuracy, undertaken with rudimentary means and extraordinary zeal. Above all, the book illuminates the niches protected and financed by the Catholic Church in which science and mathematics thrived.

Superbly written, "The Sun in the Church" provides a magnificent corrective to long-standing oversimplified accounts of the hostility between science and religion.

Genres: History, Science, Astronomy, History Of Science, Religion, Nonfiction, Architecture

384 pages, Paperback

First published January 1, 1999

Reviews

[John Vandike · Rating 5 out of 5]

This one has sat on the shelf for a while, published in 1999 at Harvard, an earlier me thought it was worth the read...but ultimately languished on that shelf for 20 years. I'll hesitate to say I regret not having read it sooner, this is a great book (for the right audience).

In its innocuous binding one might anticipate a lighter work around the incorporation of sunlight into cathedrals. In fact, reader, you will find yourself in a wonderful journey through the pivotal (contentious) relationship between the Catholic church and science in the six centuries from the Dark Ages through to the Enlightenment.

Astronomy in Europe had largely been in stasis since the period of Ptolemy and his Greek brethren pre-dating the Romans. When interest was rekindled, principally to accurately calculate Easter, the church responded with a vengeance. Scientists were brought to bear on the question: Copernicus, Galileo, Cassini and mathematicians to reduce the data.

All of this you will discover for yourself if you read the book.

Where the book really shines is that it pulls no punches with respect to terminology, science or the math. Readable prose is intermixed with the math and extensive diagrams explaining how European churches constructed in the era were used to tell time. It is definitively not an easy read, many of the 'characters' are unfamiliar to newcomers of the period. The author also assumes a fairly scientific reader, Mont that you can't get a lot out of the book without a working knowledge of astronomical, math, architectural and Catholic religious terms: prep yourself for a fair amount of time researching as you go.

And where the book falls short is really through no fault of its own. It is an academic press work, it's a bit dry, fairly mathematical. But, overall, readable for any reader interested in the relationship between Catolicism and science, architecture and astronomy, even just the accounting of time.

[Vera Versteeg · Rating 5 out of 5]

A delightfully nerdy book concerning all aspects of solar metrology in Renaissance Europe. Included are astronomical diagrams and details of where one can find extant meridiana. Also included is a detailed history of the scientists, clergy, and patrons of these endeavors. The writing sparkles with wit and even poetry at times. I just wish it included a timeline and cast of characters.

[Matthew · Rating 4 out of 5]

This book was recommended to me by a science historian, and is unusual in that it is both a history book and a science book.
As an account of history, it is magnificent. Thoroughly well-researched, with a comprehensive cast of characters, Heilbron succeeds in bringing the seventeenth and eighteenth centuries to life, with all the political and religious aspects surrounding accurate calendaring, developing astronomical methods and controversial (Copernican) ideas. The Cassini family played a central role in the narration, and it was especially interesting to learn of the genius of Gian Domenico Cassini.
As a science book, it is also wonderful. The book is replete with astronomical tables and geometrical diagrams illustrating important points at the cutting edge of astronomy at the time. Descriptions of the meridian lines built in several cathedrals around Italy and France during this time period form the majority of the book, with in depth analysis of the various challenges each one faced along with their benefits and contributions to science.
The interweaving of historical narration with mathematical geometry tends to break the flow of the book a little, but the decision to include mathematics in the book, while perhaps restricting the potential readership, was ultimately a good one, making it stand out in a genre where equations are often shunned in favor of descriptive analogies.

[Argum · Rating 3 out of 5]

So much science in this book like real nitty gritty equations and instrument descriptions and detailed drawings. I get very much more than I bargained for and it took me months to finish. I had heard reference to this book in another book by Brother Guy of the Vatican Observatory and was expecting more a history of science overview level so if you go in knowing it is more literally a science book you will be better start than me. It really is fascinating once you get through the math or not if you love astronomy. The use of churches as astronomical devices is rich and varied and incredibly important. Really read in the interest of learning more about the storied history of Vatican and science being partners, not the adversaries that most Americans are wrongly taught, this didn't disappoint. It was just a much denser read than I had wanted or expected

[Abby · Rating 4 out of 5]

This was the first book I read on Archeo-astronomy, and I have love the subject ever since. Specifically it deals with how the Catholic Church knew when to celebrate Easter. Figuring out when Easter is more complicated than you would think. It is the first Sunday, after the first full moon, after the vernal equinox. So the church built “sun lines” in the cathedral and watch the sun shine on each day. (These are sort of like the Rose Line in the DaVinci Code but they served a different purpose.) When it neared the equinox they new it was time to start Easter preparations. The lines are really beautiful, and it is really interesting the way they figured everything out. I would recommend this book to anyone who likes archeology or astronomy.

[Michal Paszkiewicz · Rating 5 out of 5]

If you are really interested in the history of astronomy, this is the book for you. Heilbron brings a surprising, largely forgotten history - the 17th and 18th century advances in Astronomy that were occurring inside Churches using holes in ceilings, despite the availability of telescopes.

The ample spaces provided by the religious buildings provided opportunity for accurate measurement that just couldn't be replicated in observatories till much later.

I particularly enjoyed reading about Cassini's story of discovery, and about his relationship with Riccioli & Grimaldi.

[Sully Augustine · Rating 2 out of 5]

I ended up skimming a library hardbound. Don't even think about it unless you got an A+ in High School Trigonometry AND you're willing to venture deep into the weeds of the author's not very clear presentation. . .

[Katie · Rating 3 out of 5]

Despite my deer-in-headlights reaction to some of the math-heavy sections, this is a very nice book to get an overview of much of the Church-sanctioned astronomical activities going on between approximately 1500 and 1800. Heilbron is clear and often pretty funny in his style.

[Brad Needham · Rating 5 out of 5]

A wonderful history of how churches, with their large and dark interiors, were used as solar observatories, to fix the date of Easter and accidentally remove the Earth from the center of the universe. In addition to being a fascinating history, it shows a good example of unintended consequences.

[Schmidleysscribblins.wordpress.com · Rating 5 out of 5]

Wonderful and full of math.

[AskHistorians]

Shows how the Catholic church funded science by building cathedrals which also acted as observatories trying to determine liturgical dates. Fairly heavy on the mathematics!