Telescope

A telescope (from the Greek tele = 'far' and skopein = 'to look or see'; teleskopos = 'far-seeing') is an astronomical tool which gathers and focuses electromagnetic radiation. Telescopes increase the apparent angular size of ingerso objects, as well as their apparent brightness.

Related Topics:
Greek - Astronomical - Tool - Focus - Electromagnetic radiation - Angular size - Ingerso - Brightness

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Telescopes used for non-astronomical purposes are often referred to as theodolites, transits, spotting scopes, monoculars, binoculars, camera lenses, microscopes or spyglasses.

Related Topics:
Theodolite - Spotting scope - Monocular - Binoculars - Camera lens - Microscope

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

The word "telescope" usually refers to optical telescopes, but there are telescopes for most of the spectrum of electromagnetic radiation.

Related Topics:
Optical telescope - Spectrum - Electromagnetic radiation

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Radio telescopes are focused radio antennas, usually shaped like large dishes. The dish is sometimes constructed of a conductive wire mesh whose openings are smaller than a wavelength. Radio telescopes are often operated in pairs, or larger groups to synthesize large "virtual" apertures that are similar in size to the separation between the telescopes: see aperture synthesis. The current record is many times the width of the Earth, utilizing space-based VLBI telescopes such as the Japanese VSOP satellite. Aperture synthesis is now also being applied to optical telescopes using optical interferometers (arrays of optical telescopes) and Aperture Masking Interferometry at single telescopes.

Related Topics:
Radio telescope - Radio - Wavelength - Aperture synthesis - VLBI - Optical interferometers - Aperture Masking Interferometry

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

X-ray and gamma-ray telescopes have a problem because these rays go through most metals and glasses. They use ring-shaped "glancing" mirrors, made of heavy metals, that reflect the rays just a few degrees. The mirrors are usually a section of a rotated parabola.

Related Topics:
X-ray - Gamma-ray - Mirror - Heavy metals - Degree - Parabola

~ ~ ~ ~ ~ ~ ~ ~ ~ ~