Light-gathering power | Wikipedia audio article
Channel: wikipedia tts
Date: 05/06/2019

This is an audio version of the Wikipedia Article:
https://en.wikipedia.org/wiki/Optical_telescope


00:01:02 1 History
00:04:51 2 Principles
00:05:27 2.1 Inverted images
00:06:36 2.2 Design variants
00:07:13 3 Characteristics
00:07:54 3.1 Surface resolvability
00:13:02 3.2 Angular resolution
00:16:38 3.3 Focal length and focal ratio
00:19:41 3.4 Light-gathering power
00:23:01 3.5 Magnification
00:24:57 3.5.1 Visual
00:26:09 3.5.2 Minimum
00:29:04 3.5.3 Optimum
00:29:46 3.6 Field of view
00:30:23 3.6.1 Apparent
00:31:27 3.6.2 True
00:32:59 3.6.3 Maximum
00:34:40 4 Observing through a telescope
00:35:26 4.1 Observable world
00:36:24 4.2 Field of view and magnification relationship
00:39:14 4.3 Brightness factor
00:42:29 4.4 Exit pupil
00:44:58 4.5 Image Scale
00:48:16 5 Imperfect images
00:49:11 5.1 The five Seidel aberrations
00:51:04 5.2 Chromatic aberrations
00:51:28 6 Astronomical research telescopes
00:52:05 6.1 Large reflectors



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SUMMARY
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An optical telescope is a telescope that gathers and focuses light, mainly from the visible part of the electromagnetic spectrum, to create a magnified image for direct view, or to make a photograph, or to collect data through electronic image sensors.
There are three primary types of optical telescope:

refractors, which use lenses (dioptrics)
reflectors, which use mirrors (catoptrics)
catadioptric telescopes, which combine lenses and mirrorsA telescope's light gathering power and ability to resolve small detail is directly related to the diameter (or aperture) of its objective (the primary lens or mirror that collects and focuses the light). The larger the objective, the more light the telescope collects and the finer detail it resolves.
People use telescopes and binoculars for activities such as observational astronomy, ornithology, pilotage and reconnaissance, and watching sports or performance arts.