Did Galileo Invent the Telescope?

By Laurie Noreau, the Rumor Detector

Agence Science-Presse (www.sciencepresse.qc.ca)

The debate has raged on for 400 years. Even though we’ve spontaneously called Galileo Galilei the inventor of the telescope, he wasn’t the first person to have merited that title. The Rumor Detector goes back four centuries to look into who really invented the telescope.

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At the Origin of the Discovery

The “eyeglasses” of the Italian genius Galileo Galilei (1564-1642) are considered to be the first astronomical instruments. And yet they undeniably saw the light of day previous to that, in the Netherlands.

In 1608, the optician Hans Lippershey was the first to apply for a patent for a device using two superimposed lenses “to see things far away as if they were nearby.” It was the invention of the telescope, but above all the invention of the diaphragm, the little cardboard disc that blocked part of the outside’s light and improved the image’s quality.

Moreover, the optician was asked to modify the instrument so that one could see inside it through two eyes rather than one. So Lippershey created the first binoculars. Those “Dutch perspective glasses” magnified images by a factor of 3.   

We can go further back than even that. In the 1558 book Magia Naturalis (Natural Magic) by the Italian scholar Giambattista della Porta, we find a description of “concave lenses” that can “make faraway things look like they are very close.” Its first use was military, to look at enemy troops. Lippershey’s diaphragm, by blocking outside light, facilitated nighttime observations.

Nonetheless, even if we can’t attribute the invention of the telescope to Galileo, he certainly perfected the instrument to the point that it provided 30 x magnification. He also seems to be the first person to have any interest in pointing the instrument towards the skies. Beginning in 1610, he published his first observations in a small astronomical treatise.

He noted that the Moon’s surface was not smooth, but that it consisted of craters and mountains. These similarities with the Earth fed the first rumors of extraterrestrial life.

When he turned his telescope towards Jupiter, he noted that the planet possessed 4 natural satellites that turned around it. The planet’s 4 largest moons, which we still call the Galilean moons, had just been discovered.

His third great contribution was his discovery that the Sun rotates. He saw sunspots on its surface that changed position over time. These imperfections proved that the Sun was not immobile, as was thought.

These three observations were revolutionary at the time. They put into question centuries-old beliefs.


Even if Galileo’s contributions to the development of the telescope and to the birth of modern astronomy are undeniable, we can’t attribute the invention of the telescope to him. The Dutch optician Hans Lippershey is the first to have applied for a telescope patent, which was turned down because the Dutch government thought it would be too easy to copy his invention. Lippershey was in turn was inspired by “perspective glasses” being used by the military. He was given a rich contract to supply the Dutch military with binoculars instead.

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