How did Galileo manufacture his telescope?

  • #1

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Hi
How can a single man without modern technology succeed in manufacturing such an engineering marvel?
Galileo wasn't even an engineer he was a scientist.
I'm interested to know that because I have always dreamt to invent and manufacture my own products just like
Jimmy neutron but found out the reality and was convinced that it's impossible but again found out Galileo very easily has done that.
 

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  • #2
gleem
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Galileo wasn't even an engineer he was a scientist.
Contrary to what some believe many physicists are skilled craftsman. Galileo was supposedly known as an excellent technician and familiar with lens making.
 
  • #3
Baluncore
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The grinding and polishing of spherical lenses is low technology that can be done by hand without any machinery.

https://en.wikipedia.org/wiki/History_of_optics#Lenses_and_lensmaking
“The earliest known working telescopes were the refracting telescopes that appeared in the Netherlands in 1608. Their inventor is unknown: Hans Lippershey applied for the first patent that year followed by a patent application by Jacob Metius of Alkmaar two weeks later (neither was granted since examples of the device seemed to be numerous at the time). Galileo greatly improved upon these designs the following year.
 
  • #4
Thanks for replying
 
  • #5
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Once while in Florence I visited a museum dedicated to the original instruments of Galileo. One only has to examine the instruments to understand the degree of craftsmanship that Galileo possessed.

https://www.museogalileo.it/en/
 
  • #6
256bits
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Quite a guy, that Galileo.
https://www.thoughtco.com/galileo-galilei-biography-1991864
Abbreviated biography.
He never married his mistress.
His son became a musician.
His daughters joined the nunnery.

The telescope and the sales of it to merchants and seamen, allowed him to become financially secure.
 
  • #7
DEvens
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If I understand it correctly, what you do is this. You rough out your chunk of glass using the usual means. Molding molten glass and such. Then you mount the sucker on a thing like a potter's wheel. And you get your polishing rouge and your cloth. And you rub and you turn and you rub and you turn. Then you do that some more. And after that you do it a *LOT* more. The higher velocity at the outer edge polishes it faster there.
 
  • #8
Ibix
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If I understand it correctly, what you do is this. You rough out your chunk of glass using the usual means. Molding molten glass and such. Then you mount the sucker on a thing like a potter's wheel. And you get your polishing rouge and your cloth. And you rub and you turn and you rub and you turn. Then you do that some more. And after that you do it a *LOT* more. The higher velocity at the outer edge polishes it faster there.
My high school physics teacher made his own telescope from glass blanks. Apparently it was horrifically spherically aberrated, but he could see through it - and that was on his first try.
 
  • #9
RPinPA
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Did Galileo manufacture his own telescopes? I thought I read there was a lens maker who had invented the telescope and Galileo purchased his lenses from that guy.

My brother is an amateur astronomer and I remember when we were teenagers he had a glass blank mounted on an oil drum, that was eventually going to be a hand-ground lens. But he tired of the project eventually and never finished it. It's a lot of work.
 
  • #10
jrmichler
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The good old resource on telescope making, apparently written some time in the 1920's, is Amateur Telescope Making, edited by Albert G. Ingalls. It is still available from Amazon as a three volume set. The figure below is from page 1 of Volume 1:
Map1.jpg

A concave mirror is made using two pieces of glass, one for the mirror and the other for the lap. Grinding compound is placed between the two pieces, and the mirror moved back and forth while walking around the lap and slowly rotating the mirror. The increased pressure during the overhang portion of the stroke preferentially grinds the outside of the lap and the inside of the mirror. Since the grinding force on the lap is equalized by walking around it, and the grinding force on the mirror is equalized by rotating it, they will be rotationally symmetric and form a portion of a sphere.

Further in the books, it is discussed how to get the desired parabolic mirror accurate to a fraction of a wavelenth of light. All of this uses technology available to Galileo, so this may well be the same techniques that he used.

There was a time when I had thoughts of making a telescope. After reading these three volumes, I changed my mind. But it was interesting reading.
 
  • #11
NASA Science:smile:
SOLAR SYSTEM EXPLORATION

Galileo's Observations of the Moon, Jupiter, Venus and the Sun

[. . .]

Galileo sparked the birth of modern astronomy with his observations of the Moon, phases of Venus, moons around Jupiter, sunspots, and the news that seemingly countless individual stars make up the Milky Way Galaxy. If Galileo were around today, he would surely be amazed at NASA's exploration of our solar system and beyond.

After learning of the newly invented "spyglass," a device that made far objects appear closer, Galileo soon figured out how it worked and built his own, improved version. In 1609, using this early version of the telescope, Galileo became the first person to record observations of the sky made with the help of a telescope. He soon made his first astronomical discovery.

[. . .]

###
https://solarsystem.nasa.gov/news/307/galileos-observations-of-the-moon-jupiter-venus-and-the-sun/

I love NASA!:kiss:
 
  • #12
Baluncore
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The good old resource on telescope making, apparently written some time in the 1920's, is Amateur Telescope Making, edited by Albert G. Ingalls.
Those good old books can viewed as images from the archives;

“Amateur Telescope Making”, edited by Ingalls; 34.6 MByte
https://ia801907.us.archive.org/32/items/in.ernet.dli.2015.37314/2015.37314.Amateur-Telescope-Making.pdf

and “Amateur Telescope Making Advanced”. Edited by Ingalls; 51.2 MByte
https://ia601601.us.archive.org/6/items/in.ernet.dli.2015.233318/2015.233318.Amateur-Telescope.pdf
 

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