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Telescopes

Telescope - the device, is designed for observation of the heavenly bodies. There are telescopes for all ranges of the electromagnetic spectrum: optical telescopes, radio telescopes, x-ray telescopes, gamma-ray telescopes. In addition, neutrino detectors are often called neutrino telescopes.Also, telescopes can be called gravitational wave detectors .

A telescopic optical system used in astronomy (to observe the heavenly bodies), in optics for various auxiliary purposes . Also, the telescope can be used as a spotting scope , to solve problems monitor remote’objects. The earliest drawings of a simple lens telescope were found in the records of Leonardo da Vinci. Built a telescope in 1608 Hans Parsha . The creation of the telescope is ascribed to his contemporary, Zacharias Jansen .

 

 

Телеском

History

 

Year the invention of the telescope, or rather spotting scope , consider 1608, when the Dutch master John of Lippershey demonstrated his invention in the Hague . However, the grant of a patent he was denied, due to the fact, that and other masters, as Zacharias Jansen from Delbourgo and Jacob, Matus from Alkmaar, already had instances of telescopes, and the last shortly after Lparse filed in the States General (the Dutch Parliament ) a request for a patent . A more recent study showed, what, probably, telescopes were previously known, in "Applications of Vitellius in", published in 1604 g. Kepler considered the path of the rays in the optical system, of lenticular lenses and downe. The earliest drawings of a simple lens telescope (both single-lens, and dahls) were discovered in the records of Leonardo da Vinci Dating from 1509, the year.

The first, who directed the telescope to the sky, turning it into a telescope, and received new scientific data became Galileo . In 1609 he created his first telescope with a three-fold increase. In the same year he constructed a telescope with an eightfold increase in length of about half a meter. Later, it created the telescope, giving a 32-fold increase: length of the telescope was about one meter, and the diameter of the o’ctive - 4,5 cm. It was a very imperfect instrument, however, with his help, Galileo made a number of discoveries.

The name "telescope" was proposed in 1611 Greek mathematician Giovanni Damson for one of the instruments of Galileo , shown at the Banquet at the Accademia dei Lincei . Galileo himself used for his telescopes Latin term perspicillum.

Optical telescopes

The telescope is a tube, mounted on the pry bar, equipped with axes for aiming at the object’s the object of observation and tracking them. Visual the telescope is about’ktiv and the eyepiece. The rear focal plane’ctive combined with the front focal plane of the eyepiece. In a focal plane’ctive instead of the eyepiece may be placed a photographic film or matrix radiation receiver . In this case,’ctiv telescope, from the point of view of optics, there fotob’s lens. The telescope is focused by means of focusers (focususing device).

Its optical design most of the telescopes are divided into:
- Lens ( the refractors or doption) - as o’ctive a lens or system of lenses.
- Mirror ( reflectors or catoptrics) - as o’Chiva used a concave mirror.
- Mirror-lens telescopes (katadin) - as o’ctive uses a spherical mirror, and lens, lenses system or the meniscus serves for compensation of aberrations.

In addition, for observations of the Sun professional astronomers use special solar telescopes , differing structurally from the traditional star telescopes.

Specifications optical telescopes

Optical telescope - this afocally system ( optical power equal to zero), consisting of’Chivu and eyepiece . The telescope increases the apparent angular size and the brightness of the observed objects’objects. The main parameters, which define the other characteristics of the telescope, there: the diameter of the o’ctive ( aperture ) and focal length’ctive.
- The resolving power depends on aperture. Is determined by the formula r=140/D, where r - angular resolution in angular seconds, and D - the diameter of the o’ctive in millimeters.
- Optical zoom is determined by the ratio G=F/f, where F and f - focal length’ctive and eyepiece.
- The diameter of the field of view of the telescope S (size of visible sky field-the size of the visible field of the sky). It is established by, the diameter of the field of view of the telescope, expressed in minutes of arc, depends on the applicable increase, S=2000/G.
- Relative aperture of A telescope - the ratio of the diameter of the o’D ctive telescope to its focal length F, where D and F are expressed in millimeters, A=D/F=1/=-1.
- The telescope , F/D =1/A=A-1.
Relative aperture of A telescope and the aperture ratio is important’ctive telescope. This is the reverse to each other value. The larger the aperture – the smaller the relative aperture, and therefore brighter the image is formed on the focal plane’ctive telescope. But this gives a less increase, which gives this o’ctiv.
- Penetrating power (optical power) m - the magnitude of the weakest stars, visible with a telescope when observing at the Zenith . For a visual telescope can be estimated by the formula of Bowen m=3+2.5 lgD+2.5 lgG. Or according to the simplified formula, m=2.1+5lgD.
Penetrating power of reflectors on 1-2 m above, than refractors. The penetrating power of a telescope depends heavily on the quality of the optics, the brightness of the sky, the transparency of the atmosphere and its tranquillity. The level and type of optical distortion (aberrations) depends on the design of the telescope, and physical properties of its optical components - lenses, mirrors, glass prisms and proofreaders.
- The linear dimensions of the diameters of the discs of the Sun and moon in the focal plane’ctive telescope is calculated by the formula l=F(30/3440), where l - the diameter of the Solar disk in focus in millimeters, and F - focal length’ctive in millimeters.
- The scale of the negatives or of the matrix u=3440/F , where u - the scale is in angular minutes per millimeter (‘/ mm), and F - focal length’ctive in millimeters. If you know linear size of the matrix, its resolution and size of pixels, then from here we can calculate the resolution of a digital image in angular minutes per pixel.

Radio telescopes

Радіотелескопи For the study of space objects’objects at radio frequencies used radio telescopes. The main elements of radio telescopes is the receiving antenna and the radiometer - sensitive radio, and receiving apparatus. Since the radio band is much wider optical, for registration of the radio emission using different designs of telescopes, depending on the range. In the long-wave region (meter range; tens and hundreds of megahertz ) use telescopes made up of many (tens, hundreds or, even, thousands) elementary receivers, usually dipoles. For shorter wavelength (decimeter and centimeter range; tens of gigahertz) use semi-or fully steerable parabolic antenna. In addition, to increase the resolution of telescopes, they’unite in interferometers . If you’Union of several single telescopes, located in different parts of the globe, in a single network, talk about a radio interferometry with superlong base (RNDB). An example of such a network can serve the American system of VLBA ( Very Long Baseline Array). With 1997 on 2003 year operated Japanese orbiting radio telescope used in VSOP ( Highly Advanced Laboratory for Communications and Astronomy), included in the network of the telescopes of the VLBA, significantly improve the resolving power of the entire network.

 

Space telescopes

Космічні телескопиEarth's atmosphere is highly transparent to optical radiation in (0,3-0,6 microns ), near-infrared (0,6 - 2 microns) and the radio (1 mm - 30 m ). Already in the near ultraviolet range with decreasing wavelength transparency of the atmosphere is much worse, resulting observations in the ultraviolet, x-ray and gamma ranges are possible only from space. The exception is the registration of gamma radiation of ultrahigh energies, suitable methods for astrophysics of cosmic rays : vysokotelym gamma photons in the atmosphere generate secondary electrons, recorded ground installations. An example of such a system may be the CACTUS telescope.

In the infrared range as much absorption in the atmosphere, however, in the field 2-8 micron has a number of Windows of transparency (as in the millimeter range), in whom it is possible to observe. In addition, since most of the absorption lines in the infrared range belongs to water molecules , infrared observations can be carried out in dry areas of the Earth(clear, at those wavelengths, generate transparency Windows in SV’in the absence of water). An example of such placement of telescope may serve as a South Pole Telescope, set on the South geographic pole, what works in the submillimeter range.

In some cases it is possible to solve the problem of the rise of atmospheric telescopes or detectors in the air by planes or stratospheric balloons . But, the greatest results are achieved with the removal of telescopes in space. Space astronomy - the only way to obtain information about the universe in korotkovolnovogo and, basically, in the infrared range; the way to improve the resolution radoihead. Optical observations from space is not as attractive in the light of modern development of adaptive optics , to greatly reduce the influence of the atmosphere on image quality, and expensive to launch a telescope with a mirror, which can be compared in size with large ground-based telescopes.

 

 

 

 

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