Date: July 25, 2010

Title: Galileo — Eclipse Chaser?


Podcaster: Mark Thompson

Organization: Galileo 1610 –

Description: Did Galileo ever have an opportunity to witness the grand spectacle of a total solar eclipse?

Bio: Mark Thompson, a professional cantor and amateur astronomer, has appeared as Galileo on radio, at community theatres and libraries, public schools, colleges and universities throughout the country. He has performed as Galileo for civic organizations, astronomy association conventions, marketing and outreach programs as well as private events and parties since 1996.

Today’s sponsor: This episode of “365 Days of Astronomy” is sponsored by the NASA Lunar Science Institute at, proud co-Founders of International Observe the Moon Night, around the globe on September 18th. More information at


Surprise, surprise… guess who’s back in the headlines and is the subject of a dozen blogs… again? our old friend, Signor Galileo Galilei. Here we are exactly 400 years since the famous astronomer shocked the world with his revelation that Jupiter has moons and today we are preoccupied with a much more mundane discovery; I am referring to the earth-shaking news that three of Signor Galilei’s mummified fingers and a tooth which were sold at an antique auction in Italy, have been reunited with his middle finger, long since safely ensconced in a small glass vessel at the Museum of Science in Florence, right next to Galileo’s famous lens, no bigger than a thumbnail, that revealed the Medicean planets.

I think it’s fairly safe to say that the grand old astronomer would be non-plussed with this recent digital discovery but I got to wondering, what would have Galileo found astronomically interesting four hundred years after his Starry Messenger was published?

Well practically everything but how about the recent total solar eclipse that occurred in French Polynesia and on Easter Island less than two weeks ago on July 11th? One might wonder- did Galileo ever have an opportunity to witness this grand spectacle? Well, he may have had the opportunity, but as far as we know from his writings and correspondence, although Galileo was among the first to study sunspots and reveal their nature, he never found himself under the umbra which is really too bad because it came pretty close to him. On October 12,1605 the tip of Italy’s boot was darkened for 2 and 1/2 minutes of totality but Galileo apparently never saw it. Most likely his teaching obligations at the University of Padua prevented him from leaving, assuming he was even interested.
Galileo was never much of a traveler anyway having spent his entire life in either Tuscany or the Venetian Republic. As far as we know, Galileo never travelled farther south than Rome. We know at least one of his contemporaries saw the eclipse in Sicily; Father Christopher Clavius the well-known Roman Jesuit priest who ultimately endorsed Galileo’s telescope discoveries which gave Galileo cover in the face of much disputation among his many jealous rivals who never gave him credit or acknowledgment that his telescope provided anything other than distorted images of the heavenly bodies. In fact, some of his opponents, Professors Magini and Horky, couldn’t see anything out of Galileo’s telescope except confusing shadows which they claimed looked like three overlapping eclipsed suns.

Actually, imagining Galileo on a cruise ship with his expensive image stabilizing telephoto lens, he the inveterate eclipse chaser trying to set a modern day umbraphile record is a romantic if not comical notion. But I suspect that if he had an opportunity to witness an eclipse Galileo would have done so, not as a gawker, but as a mathematician instead. It was always about measuring for him. Galileo would have felt right at home with those folks who purposely avoid the centerline, choosing instead to place themselves at the edge of totality’s path so as to best take parallax measurements of the sun’s diameter, or study Baily’s Beads to determine the moon’s libration. A more accurate image is of our Galileo with his sketchpad at the ready, carefully noting and drawing the angle of the emerging shadow bands just before 2nd contact.

But going back to July, 1610– Galileo has more pressing needs. He is about to resign from the Venetian Republic and return to his native Tuscany as the Chief Mathematician and Philosopher to the Grand Duke to whom he has dedicated those new moons he has recently discovered. New challenges await him there and life is about to get a lot more complicated.

End of podcast:

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