Learning About the Three Telescope Types

Since the Renaissance, scientists have been using telescopes built originally by people who made glasses and made more efficient by the likes of Galileo. Telescopes use light and lenses to focus the light on objects in great detail. What happens to the light is it converges and you see an image that is much bigger than what you are actually looking at. The light is so focused and concentrated that you can see a small item clearly and in a large image. All telescopes work the same way, buy using focused light to enlarge images. There are actually three telescope types:

Refracting Telescopes

One of the telescope types is the refracting telescope. This type of telescope has curved mirrors that focus the light and enlarge the image instead of using lenses, which focus the light. The curved glass works the same way a prism does and bends the light which allows it to focus. Other common items that use light refraction are binoculars and the telephoto lenses for your camera.

Not all refracting telescopes are perfect, though, because a bad design can cause blurry images from the variations of colors that will be seen. This phenomenon is referred to as chromatic aberration. Spherical aberrations are also possible and they occur when the curved lenses are not perfect and light is reflected improperly. It is not possible to utilize the refracting telescope on a larger scale because the weight of the lenses causes distortion from sagging. This limits their usefulness for large scale scientific research projects.

Reflecting Telescopes

The second of the telescope types is the reflecting telescope. This type of telescope is similar to a refracting telescope except that the light does not go through a lens. Instead, light is reflected off mirrors made of curved glass. The first reflecting telescope was perfected by Isaac Newton after many attempts in earlier times to change the refracting telescope to a reflecting telescope. There is a reflecting telescope named after Isaac Newton to honor his contributions.

Between the two telescope types, reflecting telescopes are preferred by larger research labs instead of refracting telescopes. This is because the curved mirrors used in reflecting telescopes are properly supported from all sides instead of only on the edges so no sagging occurs. It is still possible to have spherical aberrations with reflecting telescopes, though, as well as a phenomenon called a coma where stars are distorted and appear pointed.

Catadioptric Telescopes

The third of the telescope types is the catadioptric telescope. This type of telescope uses the technology of both reflecting and refractive telescopes, which helps reduce or eliminate many of the problems the two have individually. The catadioptric telescope has a problem of its own, though. Since there is often an extra mirror in the tube where light would normally go through, it can reduce the light on the image.

The catadioptric telescope is a popular product because it is easy to manufacture and it can enlarge images to a great degree. These telescopes are meant more for the average person, though, than for scientists since most experts prefer reflective telescopes.

The catadioptric telescope combines the best of the other two telescope types into one model. It shows how far telescopes have come and the scientific improvements that have been made that allow this to happen. Telescopes are a great learning tool no matter which one you use and we can all learn from what they have to tell us about every day items.