What is the telescope?

Dan Humby
The telescope is an instrument that helps in the viewing of distant objects by taking in light. Depending on the type of telescope and how it works, the light can be taken in and manipulated in a variety of different ways to make an image of something really far away appear to us up close. It is one of the greatest technological advancements of all time, and has changed a lot and evolved into many different forms since the first practical telescope was invented and presented in the netherlands in 1608.
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The first telescope

The first telescope was invented in October of 1608. It was very simply and consisted of two lenses, one concave and one convex. This telescope created about a 3-4 times magnified image of an object it was looking at. It was the first step into something that has improved so much over the centuries to produce things like the Hubble Space Telescope.
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Early Improvements

The first telescope consisted of two simple lenses, one concave, the other convex. The early improvements made to the first telescope were simple as well. The first improvement on it was made by Galileo, who added a convex objective lens, and a concave eyepeice. This telescope still had a very narrow field of view though, as it really only took in light coming straight at. Johannes Kepler made a simple but great improvement shortly after, by adding a convex lens at BOTH ends of the telescope instead of the eyepeice, allowing it to take in a much wider field of view. but because of this design, the image was inverted. the focal length also became a problem because in some cases you would need a telescope ridiculously long just to bring an image into focus.
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Refracting Telescope to Reflecting

During the early stages of telescopes, they had used lenses to take in light and magnify images. in 1672, Isaac Newton made the first reflecting telescope, which used mirrors to take in and magnify light. The lenses that would normally be in a refracting telescope were replaced with curved mirros to make the relfecting telescope Because mirros dont refract light, these telescopes eliminate chromatic aberration (the blurred light arround defined objects).
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The Modern Day Telescope

Modern *optical* telescopes essentially work the same way as old relfecting telescopes do. But over the yeas they have been modified and tweeked to be extremely accurate and efficient. refracting telescopes arn't really used for scientific purposed because they present many problems and inaccuracies when working with them. The picture below is a big reflecting telescope mounting in an observitory dome. This shows how telescopes have advanced from so long ago to present day.
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Telescopes and Prism Binoculars

Binoculars, Telescopes, and many other things are in the same family of altering and magnifying light. Improvements and alterations have been made over and over again over the years, spring completely new inventions such as binoculars, and advancing old ones like the telescope;. Although obviously there are similarities between binoculars and telescopes, there are also many differences. Some characteristics of prism binoculars are:
  • eye piece offsets the lenses
  • without the prisms to correct the image, it would appear inverted
  • focuses image by moving the sets of lenses closer or further from each other
  • image is smaller when looking through the objective lens
How they work is light travels through the eye piece, then hits the two prisms, turning it upright and the right way around
It's easy to see how an invention such as the telescope has been minimized, and formed into something such as binoculars. It has been improved upon and made much more accurate and efficient.


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The design of this as you can see was inspired and has it's roots at the telescope (using lenses to take in light from an object and produce a magnified image) but one thing that seperates greatly from telescope design is the use of prisms to turn the image upright (where it would normally be inverted).
If a prism had been used in reflectin telescopes back when they were first created, then the nasty problem of always getting an inverted image could have been fixed.

Telescopes and the Zoom Lens

The zoom lens changes the focal lengths by changing the distance between the converging and diverging lens.
As The lenses move further apart, the image gets bigger. This is because the beams of light that pass through the lens have more room to spread out and see a larger picture. Like a projector, the further away you move it from a screen, the larger the image on screen gets as more beams of light cover a larger area. The exact opposite is applied as the lenses come closer together.
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Yet another innovation that got it's roots from the lens magnifications first seen in the telescope. This concept of moving lenses can be (and has been) used in telescopes. This way you can change the severity of magnification depending on what you want to see. This is very convienent for everyday use, specifically in the camera.

How Telescopes Have Effected Society

Although you may not make the connection at first, without telescopes, satellite phones, satelite TV, GPS systems, cameras, all wouldn't be possible. without telescopes improvements, space exploration likely wouldnt have been possible or would have taken much longer to come to. So everything that uses space such as a GPS system wouldn't be possible. Also the vast knowledge base we have of space would be non existent. we would never have looked into space in the first place, we wouldn't have been able to. Also cameras, likely would not have been invented if it wasn't for the telescope. the potential of the lens wasn't realized until it was truely harnessed in the telescope. if it wasn't for the lens, cameras wouldn't exist. We as a society owe a lot to the scientists that turned they're inventions to the skys.

References

http://galileo.rice.edu/sci/instruments/telescope.html
http://www.aip.org/history/cosmology/tools/tools-first-telescopes.htm
http://www.antiquespectacles.com/telescopes/telescopes.htm
http://www.youtube.com/watch?v=750YGJ2JXkA&feature=related
http://www.squidoo.com/Porro-Prism-Binoculars
http://electronics.howstuffworks.com/camera.htm
http://www.physics.utoronto.ca/~jharlow/teaching/phy132f10/lec06.pdf
http://electronics.howstuffworks.com/camera2.htm
http://www.universetoday.com/15968/refractor-telescope/