Astronomy

Differences between Refracting and Reflecting Telescopes



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The differences between refracting and reflecting telescopes are quite simple. A refractor style telescope is the defacto design of spotting scopes and solar telescopes, as well as for planetary and bright object viewing. A refractor is a very simple design. The light is focused through the lens and is then sent directly to the eyepiece of the telescope. This is a relatively straight line approach only altered by the lens itself.

In a reflecting style telescope, there is no lens. It is simply a series of precisely aligned mirrors which bounce the light through various checkpoints in the telescope tube. This gives reflectors a far greater focal length than a similar sized refractor telescope.

Refractors are typically used for landscape viewing as well they excel at providing sharp vivid views of brighter celestial objects. The reason most refractor telescopes cost so much is because the lens is the key component, which requires high grade, very precise lens elements.

A reflector comes in many different styles. Newtonian, Cassegrain (a few different designs for this sub type) and a couple of others. The most common are Newtonian and Cassegrain styles. They have no lens per say. All of the light that enters the tube is sent along a complex path of mirrors until it hits the eyepiece. This gives reflectors a far greater aptitude for high magnification. It is also noteworthy that because they only have mirrors instead of a lens like a refractor, the price of your basic Newtonian reflector is far smaller than a good quality refractor. Therefore you can have a far greater telescope aperture, (light gathering ability) than a similar priced refractor. This makes most reflector scopes ideal for viewing what are known as “faint fuzzies” - the faint, distant and diffuse objects that can challenge some observers.

The simplest type of reflector, the Newtonian, will have a focal length of roughly double that of a similar sized refractor. The more complex types will have 3 or 4 times greater focal length.

Yet still different styles will excel at different areas. Refractors are great at providing stunning views of the moon, planets, sun, and bright objects such as binary stars. A reflector is great at viewing deep sky objects such as nebula, galaxies and things of that nature.

Here a few perks of the two main styles.

Refractors: - Very large aperture/cost ratio

-          Crystal clear optics

-          Robust uses. Land and astronomy.

Reflectors: - Low aperture/cost ratio for the simple types such as Newtonian

-          Amazing views of objects that would be beyond reach of similar refractors

-          Extreme ease of use, absolutely great for beginners.

-          Higher magnification potential than refractors (assuming conditions allow such high magnifications)

-          Most people in astronomy will begin with a 150mm-200mm aperture Newtonian, which speaks volumes about how wonderful they are.

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