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History of telescopes

History of telescopes

Often credited with inventing the first telescope Hans Lippershleyu from Holland, 1570-1619 years, but almost certainly it was not a pioneer.

Rather, he simply did Telescope popular and in demand.

But do not forget to apply in 1608 for a patent on a pair of lenses arranged in a tube. He called the device a telescope.

However, his patent was rejected because of his invention seemed too simple.

By the end of 1609 small telescopesthanks Lippershleyu became common throughout France and Italy. In August 1609, Thomas Harriot refined and perfected an invention that allowed astronomers to see the craters and mountains on the moon.

The big break came when Italianmathematician Galileo Galilei heard about the attempt to patent the Dutchman lens tube. Inspired by the discovery, Galileo decided to make such a device for yourself. In August 1609 Galileo made the first telescope in the world complete. At first it was just a telescope - a combination of spectacle lenses, today it would be called a refractor. Before Galileo, likely, very few people knew to use for the benefit of astronomy this tube. Due to the instrument Galileo discovered the craters on the moon, proved its sphericity, discovered four moons of Jupiter, the rings of Saturn.

The development of science allows you to create more powerfultelescopes that allowed to see a lot more. Astronomers began to use lenses with a long focal length. Sami telescopes have become impossibly huge pipes and, of course, were not easy to use. Then they invented a tripod.

By 1656 Christians made Gyuyens telescopeincreases 100 times the observed objects, the size of it was more than 7 meters, the aperture - about 150 mm. This telescope has already referred to the level of today's amateur telescopes. For 1670 years the 45-meter telescope was built, which further increased the facilities and give a wider angle of view.

But even ordinary wind could be an obstacleto provide a clear and high-quality images. Telescope began to grow in length. Discoverers, trying to make the most of this instrument, they relied on the outdoor optical law: reduction of chromatic aberration of the lens comes with an increase in its focal length. To remove chromatic noise, the researchers made the most incredible length telescopes. These tubes, which are then called telescopes, reaching 70 meters in length and brought a lot of inconvenience to work with them and set them up. Disadvantages refractors forced great minds to look for solutions to improve the telescope. The answer and a new way was found: the collection and focusing of rays become made using a concave mirror. Refractor reborn as a reflector, is completely freed from the chromaticity.

The merit of this wholly ownedIsaac Newton, that he was able to give new life to a telescope with a mirror. His first reflector has a diameter of only four centimeters. A first mirror for a telescope with a diameter of 30 mm it is made of an alloy of copper, tin and arsenic in 1704. The image is clear. By the way, his first telescope still carefully kept in the astronomical museum in London.

But for a long time could not get opticiansmake full mirror for reflectors. Year of birth of a new type of telescope is considered to be 1720, when the British built the first functional reflector with a diameter of 15 centimeters. It was a breakthrough. In Europe, there was a demand for portability, compact telescopes almost two meters long. About 40-meter pipes refractors have forgotten.

XVIII century could well be considered as the century of the reflector, if not for the discovery of the English opticians: magic combination of two lenses of the krona and flint.

Two-mirror telescope system proposedFrenchman Kassegrenom. To realize his idea fully Cassegrain could not because of lack of technical possibilities of the invention need a mirror, but today his drawings realized. It telescopes Cassegrain and Newton considered the first "modern" telescope, invented in the late XIX century. By the way, the Hubble Space Telescope working just on the principle of the Cassegrain telescope. A fundamental principle of Newton using a concave mirror used in the Special Astrophysical Observatory in Russia since 1974. The heyday of refractory astronomy occurred in the XIX century, when the diameter achromatic lenses gradually grew. If in 1824 the diameter was still 24 centimeters, then in 1866, its size has doubled, in 1885 he began to make 76 centimeters (Pulkovo Observatory in Russia), but by 1897 invented ierksky refractor. One can calculate that in 75 years the lens lens grew at a rate of one centimeter per year.

By the end of the XVIII century compact comfortable telescopesreplaced the bulky reflectors. Metal mirrors also were not too practical - expensive to manufacture, as well as dimming of the time. By 1758 with the invention of two new types of glass: light - crowns - and heavy - flint - an opportunity to create doublets. The well and took advantage of the scientist George. Dollond, who made the doublet lens, later called dollondovym.

After the invention of achromatic lensesrefractor victory was absolute, had only improved refracting telescopes. About concave mirrors forgotten. To revive them back to life failed hands of amateur astronomers. So William Herschel, an English musician, in 1781 discovered the planet Uranus. His discovery was not equal in astronomy since antiquity. Moreover, Uranus was discovered by a small homemade reflector. The success prompted Herschel to begin production of larger reflectors. Herschel in the studio with his own mirror alloyed copper and tin. . The main work of his life - a large telescope with a mirror diameter of 122 cm This telescope discoveries were not long in coming: Herschel discovered the sixth and seventh satellites of the planet Saturn. Another, who became equally famous amateur astronomer, English landowner, Lord Ross invented the reflector with a mirror diameter of 182 centimeters. Through the telescope, he discovered a number of unknowns spiral nebulae.

Telescopes Herschel and Russia have manydrawbacks. Lenses from a mirrored metal were too heavy, reflect only a small part of the light falling on them and dimmed. It needed a new perfect material for the mirrors. This material proved to glass. French physicist Leon Foucault in 1856, tried to insert a reflector mirror of silvered glass. And the experience was a success. Already in the 90s amateur astronomer from England built reflector for photographic observations glass mirror 152 centimeters in diameter. Another breakthrough in telescope making was obvious.

This breakthrough was not without the participation of Russianscientists. I'M IN. Bruce became famous for the development of special metal mirrors for telescopes. Lomonosov and Herschel, independently of one another, invented the telescope entirely new structure in which the main mirror tilts without a second, thereby reducing the loss of light.

German optician Fraunhofer placed on the conveyorproduction and improved the quality of the lenses. And today in the Tartu Observatory is a telescope with a whole working Fraunhofer lens. But the Refractors German optics were not without flaw - chromaticity.

It was only towards the end of the XIX century invented a new methodlens production. Glass surfaces have begun to process silver film that was applied to the glass mirror by the action of grape sugar in the salt of silver nitrate. These entirely new lens to reflect 95% of light, unlike the old lenses bronze, reflecting only 60% of the light. L. Foucault made reflectors with parabolic mirrors, changing the shape of the mirror surface. At the end of the XIX century Crossley, an amateur astronomer, turned his attention to the aluminum mirror. He bought a glass concave parabolic mirror diameter of 91 cm was immediately inserted into the telescope. Today, telescopes with such huge mirrors set in modern observatories. While growth slowed refractor, reflector telescope development gathered momentum. From 1908 to 1935, various observatories of the world have built more than a dozen reflectors with a lens greater than ierksky. The biggest telescope is installed in the Mount Wilson Observatory, has a diameter of 256 centimeters. And even this limit was surpassed very soon doubled. In California, a reflector mounted American giant that today it is more than fifteen years.

More than 30 years ago, in 1976, Soviet scientistsWe built the 6-meter telescope BTA - Large Azimuth Telescope. By the end of the XX century ARB considered the world's largest telescope BTA inventors were innovators in the original technical solutions, such as alt-azimuth system with the knowledge of the computer. Today, these innovations are used in almost all the giant telescopes. At the beginning of the XXI century BTA pushed in the second dozen major telescopes in the world. A gradual degradation of the mirror from time to time - for now the quality has fallen by 30% from the original - it makes it a historical monument in science.

To a new generation of telescopes are twolarge telescope - the 10-meter twin KECK I and KECK II optical infrared observations. They were established in 1994 and 1996 in the United States. They gathered with the help of the US Keck Foundation, after which they are named. He has given more than 140 000 dollars for their construction. These telescopes the size of an eight-story building and weighing over 300 tons each, but they work with the highest precision. The primary mirror 10 meters in diameter composed of hexagonal segments 36, operating as a single reflecting mirror. Established these telescopes in one of the best place on earth for astronomical observations -. In Hawaii, on the slopes of an extinct volcano Manua Kea height of 4200 m By 2002, these two telescopes are located at a distance of 85 meters of each other, we began to work in the interferometer, giving the same angular resolution as the 85-meter telescope.

The history of the telescope has come a long way - fromItalian glassmakers to modern giant telescopes, satellites. Modern large observatory has long been computerized. However, many amateur telescopes and the Hubble type devices are still based on the principles of work, invented by Galileo.

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