How Does a Refracting Telescope Work?

A refracting telescope consists of three main parts. They are the objective lens, the eyepiece lens, and a tube to put the lenses in. The objective lens is at the front of the telescope. It bends the light so that it focuses at one point. The eyepiece lens magnifies the image so it’s easier to see. However, refracting telescopes are far from perfect. They have two major problems. One problem is that because light is bent the pictures are blurry. The other problem is that the lens of the telescope has to be a certain size. This means the telescope has a limit on how far it can see.

The Refracting Telescope’s History

A Dutch glasses maker named Hans Lippershey made the first refracting telescope in 1608. In 1611 the design of the telescope was improved to let you look at the image from above instead of on an angle. Galileo was the first person to use a reflecting telescope to look at space. With the telescope he mapped the surface of the moon and discovered 4 of Jupiter’s moons.

How Does a Reflecting Telescope Work?

Reflecting telescopes have 3 main parts. The first is a large objective mirror. The job of this mirror is to reflect the light onto a reflecting mirror. It reflects the light into the eyepiece of the telescope. The eyepiece is a lens that magnifies the image so that’s it’s easier to see. The third piece is the tube that holds them it together. Reflecting telescopes are far better than refracting telescopes. They can see much farther away and see much dimmer objects.

The Reflecting Telescope’s History

An astronomer from Scotland designed the first reflecting telescope in 1663. However, Sir Isaac Newton built the first reflecting telescope in 1668.

How Does a Radio Telescope Work?

Most telescopes "see" by using light. However, radio telescopes see with radio waves. Radio telescopes send out radio waves. These radio waves bounce off other objects and when the radio waves come back, computers can make maps with the radio waves. This is called radar mapping. Most radio telescopes are made up of a giant dish that collect the radio waves and sends the information into a computer. A radio telescope works like a fish detector. It sends out radio waves and by timing how long the radio waves take to get back you can find out if there are fish under your boat.

The Radio Telescope's History

The first dish radio telescope was made be an American engineer in the late 1930's. He made the telescope in his own back yard. It had a 32-foot wide dish. The maker of this telescope used it to look into space and he detected strange radio transmissions. This led to people becoming interested in radio telescopes.

Links to Other Sites on Telescopes

 Reflecting Telescope Diagram

 Another Reflecting Telescope Diagram

 Refracting Telescope Diagram

Space Today, Tomorrow, and Always. </J0112188 > Last Visited: February 2002.

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All pictures courtesy of NASA unless otherwise noted