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HISTORY OF THE TELESCOPES

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History of telescopes</a>

Often the invention of the first telescope is attributed to Hans Lipperchlei from Holland, 1570-1619, but almost certainly he was not a pioneer.

Most likely, he simply made the telescope popular and in demand.

But at the same time he did not forget to file a patent application in 1608 for a couple of lenses placed in the tube. He called the device a telescope.

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

By the end of 1609, small telescopesThanks to the Lipper-sash became widespread throughout France and Italy. In August 1609, Thomas Harriot finalized and perfected the invention, which allowed astronomers to consider craters and mountains on the Moon.

A big breakthrough came about when the ItalianMathematician Galileo Galilei learned of the Dutchman's attempt to patent a lens tube. Inspired by the discovery, Galileo decided to make such a device for himself. In August 1609 it was Galileo who produced the world's first full-scale telescope. At first it was just a telescope - a combination of spectacle lenses, today it would be called a refractor. Prior to Galileo, most likely, few people guessed to use this tube for the benefit of astronomy. Thanks to the device, Galileo opened craters on the Moon, proved its sphericity, discovered four satellites of Jupiter, the rings of Saturn.

The development of science made it possible to create more powerfulTelescopes, which gave to see much more. Astronomers began using lenses with a large focal length. The telescopes themselves turned into huge, unbearable pipes and, of course, were not convenient to use. Then for them invented tripods.

By 1656 Christian Huyens had made a telescope,Increasing in 100 times the observed objects, its size was more than 7 meters, the aperture - about 150 mm. This telescope is already referred to the level of today's amateur telescopes. By the 1670s a 45-meter telescope was built, which further increased the objects and gave a larger angle of view.

But even the usual wind could serve as an obstacleTo get a clear and high-quality image. The telescope began to grow in length. The discoverers, trying to squeeze the maximum out of this device, relied on the optical law discovered by them: a decrease in the chromatic aberration of the lens occurs with an increase in its focal length. To remove the chromatic interference, the researchers made telescopes of the most incredible length. These pipes, which were then called telescopes, reached 70 meters in length and caused a lot of inconvenience in working with them and their tuning. Disadvantages of refractors forced great minds to look for solutions to how to improve the telescope. The answer and a new way was found: collecting and focusing rays was made using a concave mirror. The refractor degenerated into a reflector completely freed from chromaticity.

This merit is wholly ownedIsaac Newton, it was he who managed to give new life to telescopes using a mirror. Its first reflector had a diameter of only four centimeters. And the first mirror for a telescope with a diameter of 30 mm was made of a copper, tin and arsenic alloy in 1704. The image became clear. By the way, his first telescope is still carefully stored in the astronomical museum of London.

But for a long time, opticians could not do it.Make full-fledged mirrors for reflectors. The 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 mobile, almost compact telescopes two meters long. About 40-meter tubes of refractors began to be forgotten.

The XVIII century could well be considered a century of the reflector, were it not for the discovery of English opticians: a magic combination of two lenses from the crown and flint.

The two-mirror system in the telescope is proposedThe Frenchman Cassegrain. Realize his idea to the fullest Cassegrain could not because of the lack of technical ability to invent the right mirrors, but today his drawings are implemented. It is the telescopes of Newton and Cassegrain that are considered the first "modern" telescopes invented in the late 19th century. By the way, the Hubble Space Telescope works just on the principle of Cassegrain's telescope. And Newton's fundamental principle with the use of a single concave mirror was used in the Special Astrophysical Observatory in Russia since 1974. The heyday of refractory astronomy occurred in the XIX century, then the diameter of achromatic objectives gradually grew. If in 1824 the diameter was still 24 centimeters, then in 1866 its size doubled, in 1885 it became 76 centimeters (the Pulkovo Observatory in Russia), and by 1897 the Irk refractor was invented. You can calculate that for 75 years, the lens lens increased at a rate of one centimeter per year.

By the end of the 18th century, compact, comfortable telescopesCame to replace cumbersome reflectors. Metal mirrors, too, were not very practical - expensive in production, as well as fading from time to time. By 1758, with the invention of two new varieties of glass: light - crown - and heavy - flint - it became possible to create two-lens lenses. Than safely and took advantage of the scientist J. Dollond, who produced a two-lens, later called Dollondov.

After the invention of achromatic lensesThe victory of the refractor was absolute, it only remained to improve the lens telescopes. About the concave mirrors have forgotten. Revive them to life managed by amateur astronomers. So William Herschel, an English musician, in 1781 discovered the planet Uranus. His discovery was not equal in astronomy since ancient times. And Uranus was discovered with the help of a small self-made reflector. Success prompted Herschel to start producing reflectors of a larger size. Herschel in his workshop with his own hand fused mirrors of copper and tin. The main work of his life is a large telescope with a mirror 122 cm in diameter. Thanks to this telescope, the discoveries did not take long: Herschel discovered the sixth and seventh satellites of the planet Saturn. Another, who became no less famous amateur astronomer, the English landowner Lord Ross invented a reflector with a mirror measuring 182 centimeters in diameter. Thanks to the telescope, he discovered a number of unknown spiral nebulae.

The telescopes of Herschel and Ross had manyShortcomings. Lens of mirror metal were too heavy, reflected only a small part of the light falling on them and faded. A new perfect material for mirrors was required. This material was glass. The French physicist Leon Foucault in 1856 tried to insert a mirror of silver-plated glass into the reflector. And the experiment was a success. Already in the 90's an amateur astronomer from England built a reflector for photographic observations with a glass mirror of 152 centimeters in diameter. The next breakthrough in telescoping 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 each other, invented a completely new design of the telescope, in which the main mirror tilts without a secondary, thereby reducing the loss of light.

German optician Fraunhofer put on the conveyorProduction and improved the quality of the lens. And today in the Tartu Observatory there is a telescope with a whole, working Fraunhofer lens. But the refractors of the German optician were also not without flaws - chromaticity.

And only by the end of the XIX century they invented a new methodMade lens. The glass surfaces were treated with a silver film, which was applied to a glass mirror by the action of grape sugar on silver nitrate salts. These principally new lenses reflected up to 95% of the light, in contrast to the old bronze lenses reflecting only 60% of the light. L. Foucault created reflectors with parabolic mirrors, changing the shape of the surface of the mirrors. At the end of the 19th century, Crosley, an amateur astronomer, turned his attention to aluminum mirrors. The concave glass parabolic mirror he bought with a diameter of 91 cm was immediately inserted into the telescope. Today telescopes with similar huge mirrors are installed in modern observatories. While the growth of the refractor has slowed down, the development of a mirror telescope has gained momentum. From 1908 to 1935, various observatories of the world built more than fifteen reflectors with a lens that exceeded the Jerk. The largest telescope is installed at the Mount Wilson Observatory, its diameter is 256 centimeters. And even this limit was soon surpassed twice. In California, mounted an American giant reflector, today its age is more than fifteen years.

More than 30 years ago in 1976 scientists of the USSRBuilt a 6-meter telescope BTA - the Big Telescope Azimutal. Until the end of the 20th century, the BRA was considered the world's largest telescope. Inventors of BTA were innovators in original technical solutions, such as the alt-azimuth installation with computer guidance. Today, these innovations are used in virtually all giant telescopes. At the beginning of the XXI century, BTA was pushed back to the second ten large telescopes of the world. And the gradual degradation of the mirror from time to time - today its quality has fallen by 30% from the original - turns it only into a historical monument to science.

The new generation of telescopes include twoLarge telescope - 10-meter twin KECK I and KECK II for optical infrared observations. They were installed in 1994 and 1996 in the United States. They were collected thanks to the help of the W. Keck Foundation, in honor of which they were named. He provided more than $ 140,000 for their construction. These telescopes are the size of an eight-story house and weigh more than 300 tons each, but they work with the highest precision. The main mirror with a diameter of 10 meters consists of 36 hexagonal segments, working as one reflecting mirror. These telescopes were installed in one of the best places on Earth for astronomical observations - in Hawaii, on the slope of the extinct volcano Manua Kea in the height of 4,200 m. By 2002, these two telescopes, located 85 m apart, began to work in the interferometer mode, Giving the same angular resolution as the 85-meter telescope.

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

HISTORY OF THE TELESCOPES Was last modified: May 21st, 2017 By Siazierf
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