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Optics: The heart of a telescope

If you've always wanted to explore the night sky with a telescope, an understanding of optics is essential. The optics in a telescope brings the universe in focus for you -- whether you're looking at the moon or a distant nebula. Here's some information on how a telescope works.

In its simplest form, a telescope consists of a tube and some optics. At one end of the tube is the objective lens. This is the large lens at the far end of the scope. The larger the diameter of the objective, the more light the telescope can gather and the brighter and clearer the image will be. Inside the tube, the light that enters the objective is bent to a focal point. At the other end of the tube, an eyepiece lens takes the light from the focus and magnifies it to the human eye. So when you point your telescope toward the moon, a complex process occurs, resulting in the magnified image of the moon you see in the eyepiece. This type of telescope is called a refractor.

If you want to study distant celestial objects, a glass lens has physical limitations. To see images of nebulas and galaxies, you need a telescope that uses another type of optics: the mirror. Mirrors do not have the optical limitations of lenses, can be larger than lenses and thus have greater light-gathering properties. In this type of telescope, there is a mirror at the end of the tube. Light hits the mirror, reaches a focal point, is picked up by a second smaller mirror and directed to an eyepiece located in the side of the tube. This type of telescope is called a reflector.

Whether refractor or reflector, the optics in a telescope gather and focus light. To see spectacular images of the moon and planets, choose a refractor. To see distant objects like galaxies, nebulas and star clusters, choose a reflector. Regardless of what type of telescope you choose, you'll be amazed at the images you see.

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About The Author:

Rita Liotta is a successful author and publisher at www.1st-at-binoculars.com.  Recommending binoculars, telescopes, rifle scopes, night vision, spotting scopes, laser sights, range finders & night vision goggles.
04-06-04