The Galileo Telescope: What’s the Big Deal?


Many people think that Galileo invented the telescope. Maybe you do too. If so, I hate to burst your bubble, but the Galileo telescope was not the first one ever made.

Why then does Galileo get so much attention related to the telescope? Who did invent it and when? Do we still have the original telescopes?

Read on and I’ll tell you a little of what we know.

Who Invented the Telescope?

Back in the early 1600s, 1608 in particular, three men independently invented the device we now call the telescope. Hans Lipperhey and Jacob Alkmaar developed it in The Netherlands. Sacharias Janssen also came up with the idea in Frankfurt, Germany.

About this same time and shortly thereafter, many others in Europe were also designing what we would normally call spyglasses.

Soon afterward in 1609 in Venice, Galileo learned of the invention and improved upon it. He first created a 3-powered telescope similar to that of the inventors. Over the next few months, he upgraded it to an 8x scope and then a 20x instrument.

Galileo telescope replica
Galileo telescope replica

Photo Credit

What Did Galileo Discover with His Telescope?

Galileo, as did his contemporaries, first made telescopes to explore the heavens. What Galileo first saw is what made his use of the telescope so much more famous and important than others.

Galileo and Donato
Depiction of Galileo presenting his telescope to Donato.

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Among other night sky objects, he was the first to see the four larger moons of Jupiter – Io, Europa, Ganymede, and Callisto. He also noted that Venus has phases like Earth’s moon. Later he (and others) discovered sunspots.

In 1610, Galileo published his findings in a treatise called Sidereus Nuncius. This pamphlet has over 70 drawings of the Moon, some constellations, and Jupiter’s moons. It also includes descriptions, explanations, and theories about what he observed.

Siderius Nuncius (Starry Message)
Siderius Nuncius (Starry Message)

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It was theories such as these that got Galileo in major trouble with the church. The church held that the Earth was the center of everything. Galileo’s discoveries proved otherwise, a fact that the church eventually acknowledged and many years later apologized for disagreeing with.

How Did Galileo Design His Telescope?

Quoting an article at The Galileo Project:

It had a plano-convex objective (the lens toward the object) with a focal length of about 30-40 inches and a plano-concave ocular with a focal length of about 2 inches. The ocular was in a little tube that could be adjusted for focusing. The objective lens was stopped down to an aperture of 0.5 to 1 inch, and the field of view was about 15 arc-minutes (about 15 inches in 100 yards). The instrument’s magnification was 15-20.

In the video mentioned below, there are good visuals of what this all looked like.

Where Is the Galileo Museum?

If you are the traveling type or simply live in the area, you can visit The Galileo Museum, or Museo Galileo, located in Florence, Italy. It opened to the public in its current version in 2010.

You can learn more about the Galileo telescope and his many other accomplishments at the museum.

You can visit the museum virtually from the comfort of your home by going to the Museo Galileo’s Virtual Museum.

At the Virtual Museum, you can watch an excellent 2-minute video about the history of the telescope. It includes Galileo’s work as well as that of other early scientists.

There is also this short article that concentrates on the Galileo telescope.

The Galileo telescope in and of itself wasn’t that big of a deal. It’s what Galileo, the meticulous scientist, did with it that makes it memorable.

If it were not for a man like Galileo, who has been called the “father of modern science” (by Albert Einstein), the fields of astronomy and optics would be much poorer today.

Gary Sonnenberg

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