Galileo Galilei, astronomer and physicist, circa 1637, painted by Justus Sustermans.
The scientist was deemed heretical by the Inquisition and subject to extended house arrest.
At the University of Pisa, he became interested in mathematics and physics.
Galileo Galilei, astronomer and physicist, circa 1637, painted by Justus Sustermans. (Photo:Wikimedia Commons, Public domain)
His work on pendulums and his invention of the thermoscope were early achievements.
He taught geometry and astronomy to students at the Universities of Pisa and Padua.
The revolutionary, even heretical, idea had yet to be proven.
Galileo’s telescopes on view at the Museo Galileo. (Photo: Sailko viaWikimedia Commons,CC BY-SA 3.0)
In 1608, Dutch spectacle makers Hans Lippershey and Zacharias Janssen, and Jacob Metius independentlycreated the first knowntelescopes.
Optics was a long-established science, and the principles of magnification behind the telescope were not new.
The next year, Galileo caught wind of this perspective glass or spyglass.
“Galileo Galilei showing the Doge of Venice how to use the telescope,” by Giuseppe Bertini, 1858. (Photo:Wikimedia Commons, Public domain)
With vast experience creating scientific instruments, he set about making one of his own.
Galileo Perfects His Spyglass
Galileo’s telescopes on view at the Museo Galileo.
However, by late 1609, Galileo had created a wood and leatherversion with 21X magnification.
Draft letter written by Galileo Galilei in August 1609 to Leonardo Donato, Doge of Venice, in which he offers his new telescope to his patron. The letter is currently held in the University of Michigan Harlan Hatcher Graduate Library’s Special Collections. (Photo:Wikimedia Commons, Public domain)
Another version, from 1610, possesses16X magnification.
These early models hadnarrow fields of viewbut they offered awhole new way of looking at the universe.
Before the telescope, the universe was studied by measurements taken with other instruments.
Tomb of Galileo Galilei in Florence. (Photo: stanthejeep viaWikimedia Commons,CC BY-SA 2.5)
Direct viewing of a phenomenon was usually limited to the abilities of the human eye.
Galileo exhibited his inventions to Italian nobles and word quickly spread of his work.
Galileo Galilei showing the Doge of Venice how to use the telescope, by Giuseppe Bertini, 1858.
(Photo:Wikimedia Commons, Public domain)
Galileo’s telescopes wererefracting telescopes.
Here’s how they worked: a concave and convex lens were connected by a long tube.
A viewing lens eyepiece on the end of the convex lens allowed someone to see the refracted image.
This setup allowed for some shocking discoveries.
He published his discoveries and sketches of what he saw in space in a famous work entitledStarry Messenger.
The letter is currently held in the University of Michigan Harlan Hatcher Graduate Library’s Special Collections.
Church and science were intimately entwined at the time.
Many supporters of geocentrism relied literally on Biblical verses referencing the movement of the sun.
Galileo, a devout Catholic, was not intending to overthrow religion.
By 1610, Galileo was actively defending heliocentrism in his correspondence and work.
In 1615, a Dominican friar wrote to the Roman Inquisition complaining about Galileo’s controversial stance.
After an investigation of these charges of heresy, Galileo was not found guilty (yet).
CopernicussRevolutionsand other books promoting the theory were banned.
Galileo himself was personally warned.
When Pope Urban VIII was elected, Galileo was in the papal good books.
However, it appears the church did not anticipate the true impact of the work.
Galileo found himself once more in front of the Inquisition which had authorized the book.
This time he was found guilty of suspected heresy and denying scripture.
Galileo, for his part, maintained he had not been a heliocentrist since its banning.
Galileo is considered a father of astronomy to this day.
His designs and uses of the telescope remain one of his most important legacies.
Today, you’re free to view the telescopes at theMuseo Galileoin Florence, Italy.
To learn more, check out their entire website dedicated toGalileo’s telescopes.
Tomb of Galileo Galilei in Florence.
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