what is the difference between the two optical telescope used in astronomy?

Question

the refracting,reflecting,catadiotrophic and the hubble space telescopes

Answer 1

Refracting is like a pirate scope... lens at the end, long with an eyepiece in line with the lens

Reflecting has a mirror at one end (so it REFLECTS). The light comes in a hole, bounces off the mirror and then is reflected into a slanted mirror into the eyepiece

The Hubble is a Reflector.

The Cadiotropic (sp) is similar to a reflector except it refold the reflected image with extremely precise lenses.

Answer 2

The three most common telescope types are the refractor, the Newtonian reflector, and the Cassegrainian reflector.

Refractors use a lens to focus light. This lens has at least two elements, because it takes more than one type of glass to focus all the colors together. A single lens acts like a prism and creates colored fringes around everything. This is called chromatic aberration. Good refractors are very expensive because of the glass types used. In the nineteenth century, refractors up to 40 inches in aperture were built. When silvered glass mirrors became practical, observatories shifted to reflectors.

The Newtonian reflector is the simplest telescope design. It consists of a concave mirror at the bottom of the tube to focus light, and a flat mirror at the other end to reflect the image out to an eyepiece in the side of the tube. This type of telescope is very popular with amateur astronomers because of its relatively low cost.

The Cassegrainian reflector is a compound telescope using two curved mirrors. It produces a long focal length in a relatively short tube. The most common variant of this telescope in amateur use is the Schmidt-Cassegrain, which has a thin corrector lens on the front.

A telescope like this with a combination of lenses and mirrors is called a catadioptric telescope. Catadioptric telescopes include Newtonian reflectors with various forms of correcting lenses. The corrector can allow for the use of a simpler mirror shape, and/or provide additional correction, such as for flatness of the image field.

The Hubble space telescopes and virtually all modern observatory telescopes are a Cassegrain variant called a Ritchey-Chrétien. It has the same optical layout as the Cassegrain, but uses different curves on the mirrors to provide better star images, especially at the edges of the field.