Telescope Astronomical Views

General Goods

Reflecting telescopes use mirrors to focus light, and since they are cheaper they can be made much larger. All major astronomical telescopes built now are reflectors. The largest optical telescopes are currently the Keck telescopes that have 10 meter mirrors and the brand new Gemini telescopes that have 8 meter mirrors.

Although optical telescopes are the type most commonly used for stargazing and amateur astronomy, lots of astronomical research is done on telescopes that look at other wavelengths of light. Each of these wavelength ranges shows us something unique about the universe and allows us to view events and objects that can't be seen with human eyes.

An optical telescope gathers and focuses light mainly from the visible part of the electromagnetic spectrum (although some work in the infrared and ultraviolet).[9] Optical telescopes increase the apparent angular size of distant objects as well as their apparent brightness. In order for the image to be observed, photographed, studied, and sent to a computer, telescopes work by employing one or more curved optical elements—usually made from glass—lenses, and/or mirrors to gather light and other electromagnetic radiation to bring that light or radiation to a focal point. Optical telescopes are used for astronomy and in many non-astronomical instruments, including: theodolites (including transits), spotting scopes, monoculars, binoculars, camera lenses, and spyglasses. There are three main types:

The astronomical telescope makes use of two positive lenses: the objective, which forms the image of a distant object at its focal length, and the eyepiece, which acts as a simple magnifier with which to view the image formed by the objective. Its length is equal to the sum of the focal lengths of the objective and eyepiece, and its angular magnification is -fo /fe , giving an inverted image.