Optical telescope

An optical telescope is an optical instrument can be regarded, with the larger one distant objects or examine with high resolution. After its structure, a distinction between the telescope ( refractor ) and the reflecting telescope.

Optical telescopes are mainly used for watching in the field ( binoculars, spotting scope ) and use of astronomical objects. In solar observations in this case an appropriate solar filter must be used. There are also other fields of use. Examples include the study of the earth's atmosphere with LIDAR telescopes, control and Scopes ( diopter ), theodolites and satellite geodesy.

The lens or mirror system of an optical telescope produced in its image plane a real image. This image can be visualized in two ways:

• Directly in the image plane (lens focal length) In the simplest case by introducing a ground-glass plate as a projection screen. In astrophotography bringing a film, a photographic plate of glass or an image sensor into the image plane, which are exposed just like in a camera.
• Through an eyepiece Here the image for the human eye is processed, so that direct observation is possible. In addition, can be changed by changing the focal length of the eyepiece, the magnification of the targeted object.

Because of their large focal length and weight telescopes (except smaller binoculars) are held by Mounts and moved. Their stability and control options are - especially when Observatories - for the performance of the telescopes essential.

Optical telescopes for scientific purposes are almost exclusively mirror telescopes today. The currently most have primary mirror 10 meters in diameter ( Keck telescopes I and II in Hawaii, composite, fragmented mirror ), or 8.2 m diameter ( Very Large Telescope VLT in Chile, operated by the European Southern Observatory, a total of four individual telescopes can be connected together with main mirrors of one ceramic block ).

The Hubble Space Telescope is an example of a large optical telescope on Earth orbit. Since you have but now learned, on the earth's surface to use the resolution of very large telescopes ( interferometry and adaptive optics), should in future projects for space telescopes in particular spectral regions are investigated, for which the Earth's atmosphere is opaque: (UV, infrared radiation, X-rays ). These are then strictly speaking, no longer to optical telescopes, but these are similar in many respects.