School encyclopedia. Meaning of observatory: modern ground-based observatories in Collier's dictionary Post on modern observatories
The starry sky is mesmerizing. Although today the pleasure of seeing the Milky Way is very difficult - the dustiness of the atmosphere, especially in cities, significantly reduces the opportunity to see the stars in the night sky. That is why a trip to an astronomical observatory becomes a revelation for the average person. And the stars again begin to inspire hopes and dreams in a person. There are about 60 observatories in Russia, the most important ones will be discussed in this article.
A little general knowledge
Modern ground-based observatories are research centers. Their tasks are much broader than just observing celestial bodies, phenomena and artificial space objects.
Modern ground-based observatories are equipped with powerful telescopes (optical and radio), and modern instruments for processing the received information. They are characterized by the presence of buildings with opening hatches or even buildings that rotate along with optical telescopes. Radio telescopes are installed outdoors.
Most observatories are located on high ground or with good all-round visibility, and are usually located at specific coordinates that are important in astronomy.
History of domestic observatories
In Russia, the first such object in a separate room appeared on the initiative of Archbishop Athanasius in 1692. The optical telescope was installed on the bell tower in Kholmogory in the Arkhangelsk region.
In 1701, the comrade and associate of Peter I, diplomat and scientist Yakov Vilimovich Bruce (James Daniel Bruce, 1670-1735) initiated the opening of an observatory at the Navigation School on the Sukharev Tower in Moscow. It was of great practical importance; there were sextants and quadrants. And it was here that the solar eclipse of 1706 was first observed.
The first official observatory appeared on Vasilyevsky Island. It was founded by Peter I, but opened under Catherine I in 1725. It has survived to this day, but as an architectural monument, under the library of the Academy of Sciences. And at one time this octagonal tower had many disadvantages, including its location within the city.
All its equipment was transported to the Pulkovo Observatory, the foundation of which took place in 1835, and it opened in 1839. For a long time, this particular astronomical observatory was the leading one in Russia, and today it has retained its position.
Today in Russia there are about 60 observatories and research centers, about 10 higher educational institutions with astronomy departments, more than a thousand astronomers and several tens of thousands of enthusiastic stargazers.
The most important
The Pulkovo Astronomical Observatory is the main one. It is located on the Pulkovo Heights, which is 19 kilometers south of St. Petersburg. It is located on the Pulkovo meridian and has coordinates 59°46"18" north latitude and 30°19"33" east longitude.
This main observatory in Russia has 119 scientific employees, 49 candidates of science and 31 doctors of science. All of them work in the following areas: astrometry (parameters of the Universe), celestial mechanics, stellar dynamics, stellar evolution and extragalactic astronomy.
All this is possible thanks to the availability of sophisticated equipment, the main one of which is one of the largest solar telescopes in Europe - the horizontal telescope ATSU-5.
There are evening and night excursions here, when you can see especially starry “black” nights. There is also a museum at this observatory, which contains exhibits illustrating the entire history of astronomy. Here you can see unique astronomical and geodetic ancient instruments.
Number two
One of the largest in Russia is the Pushchino Radio Astronomy Observatory of the ASC FIAN. It was founded in 1956 and today is one of the most well-equipped: radio telescope RT-22, meridian-type radio telescopes with two antennas DKR-100 and BSA.
It is located in the city of Pushchino, Moscow region, its coordinates are 54°49" north latitude and 37°38" east longitude.
An interesting fact is that in windy weather you can hear the “singing” of telescopes. They say that in the film “War and Peace” Sergei Bondarchuk used a recording of this particular hysterical song.
Astronomical Observatory of Kazan University
In the center of Kazan, on the campus, there is an ancient observatory, founded at the Department of Astronomy in 1833. This amazing building in the classicist style is always popular among city guests. Today it is a regional center for training and use of satellite navigation systems.
The main instruments of this observatory are the Merz refractor, the Repsold heliometer, the George Dollon telescope, the equatorial and the precise time clock.
One of the youngest
The Baikal Astrophysical Observatory was opened in 1980. It is located in a place with a unique microastroclimate - local anticyclones and small rising air currents from Lake Baikal create unique conditions for observations here. It belongs to the Institute of Solar-Terrestrial Physics of the Russian Academy of Sciences and is equipped with unique equipment: a large solar vacuum telescope (the largest in Eurasia), a full solar disk telescope, a chromospheric telescope, and a photoheliograph.
The main activities of this Russian observatory are observing the fine structure of solar formations and recording solar flares. No wonder it is called the Solar Observatory.
The largest telescope
The largest astronomical center in Russia is the Special Astrophysical Observatory. It is located near Mount Pastukhovaya in the North Caucasus (village of Nizhny Arkhyz, Karachay-Cherkess Republic). It was founded in 1966 to operate the largest telescope in Russia - the Large Azimuthal Telescope. Work on its assembly took 15 years and today it is a telescope with a maximum six-meter optical mirror. The height of its dome is 50 meters and its diameter is 45 meters.
In addition to it, there are also 2 more telescopes of slightly smaller sizes.
There are excursions for tourists here, and in the summer this telescope is visited by up to 700 people a day. Tourists also go to this remote area to see the icon of the Face of Christ. This is a unique rock icon, which is located a kilometer from the observatory.
Here, in Arkhyz, the past seems to come into contact with the future and humanity’s desire for the stars.
Our own sky is not enough for us
In 2017, a Russian-Cuban project was launched to equip two observatories in Cuba. There is active discussion about choosing the most optimal astroclimatic and meteorological conditions for the placement of these autonomous and fully automated telescopes.
The goal of the project involves collecting and analyzing information about the spectral, positional and photometric characteristics of various space objects.
Much of the southern sky is not visible from most observatories in Europe and the United States, although the southern sky is considered especially valuable for astronomy because it contains the center of the Milky Way and many important galaxies, including the Magellanic Clouds, two small galaxies neighboring ours.The first maps of the southern sky were compiled by the English astronomer E. Halley, who worked from 1676 to 1678 on the island of St. Helena, and the French astronomer N. Lacaille, who worked from 1751 to 1753 in southern Africa. In 1820, the British Bureau of Longitude founded the Royal Observatory at the Cape of Good Hope, initially equipping it with only a telescope for astrometric measurements, and then with a full set of instruments for a variety of programs. In 1869, a 122 cm reflector was installed in Melbourne (Australia); Later it was moved to Mount Stromlo, where after 1905 an astrophysical observatory began to grow. At the end of the 20th century, when conditions for observations at the old observatories in the Northern Hemisphere began to deteriorate due to heavy urbanization, European countries began to actively build observatories with large telescopes in Chile, Australia, Central Asia, the Canary Islands and Hawaii.
Observatories above the Earth. Astronomers began using high-altitude balloons as observation platforms back in the 1930s and continue such research to this day. In the 1950s, the instruments were mounted on high-altitude aircraft, which became flying observatories. Extra-atmospheric observations began in 1946, when US scientists using captured German V-2 rockets raised detectors into the stratosphere to observe ultraviolet radiation from the Sun. The first artificial satellite was launched in the USSR on October 4, 1957, and already in 1958 the Soviet Luna-3 station photographed the far side of the Moon. Then flights to the planets began and specialized astronomical satellites appeared to observe the Sun and stars. In recent years, several astronomical satellites have been constantly operating in near-Earth and other orbits, studying the sky in all spectral ranges.Work at the observatory. In earlier times, the life and work of an astronomer depended entirely on the capabilities of his observatory, since communications and travel were slow and difficult. At the beginning of the 20th century. Hale created the Mount Wilson Observatory as a center for solar and stellar astrophysics, capable of conducting not only telescopic and spectral observations, but also the necessary laboratory research. He sought to ensure that Mount Wilson had everything necessary for life and work, just as Tycho did on the island of Ven. To this day, some large observatories on mountain peaks are closed communities of scientists and engineers living in dormitories and working at night according to their programs.But gradually this style is changing. In search of the most favorable places for observation, observatories are located in remote areas where it is difficult to live permanently. Visiting scientists stay at the observatory from several days to several months to make specific observations. The capabilities of modern electronics make it possible to conduct remote observations without visiting the observatory at all, or to build fully automatic telescopes in hard-to-reach places that independently operate according to the intended program.
Observations using space telescopes have a certain specificity. At first, many astronomers, accustomed to working independently with the instrument, felt uncomfortable within the confines of space astronomy, separated from the telescope not only by space, but also by many engineers and complex instructions. However, in the 1980s, many ground-based observatories moved telescope control from simple consoles located directly at the telescope to a special room filled with computers and sometimes located in a separate building. Instead of aiming the main telescope at an object by looking through a small finderscope mounted on it and pressing buttons on a small hand-held remote control, the astronomer now sits in front of the TV guide screen and manipulates a joystick. Often, the astronomer simply sends a detailed program of observations to the observatory via the Internet and, when they are carried out, receives the results directly into his computer. Therefore, the style of working with ground-based and space telescopes is becoming increasingly similar.
Optical observatories. The location for the construction of an optical observatory is usually chosen away from cities with their bright night lighting and smog. Usually this is the top of a mountain, where there is a thinner layer of atmosphere through which observations have to be made. It is desirable that the air is dry and clean, and the wind is not particularly strong. Ideally, observatories should be evenly distributed across the Earth's surface so that objects in the northern and southern skies can be observed at any time. However, historically, most observatories are located in Europe and North America, so the skies of the Northern Hemisphere are better studied. In recent decades, large observatories have begun to be built in the Southern Hemisphere and near the equator, from where both the northern and southern skies can be observed. The ancient volcano Mauna Kea on the island. With an altitude of more than 4 km, Hawaii is considered the best place in the world for astronomical observations. In the 1990s, dozens of telescopes from different countries settled there. Tower. Telescopes are very sensitive instruments. To protect them from bad weather and temperature changes, they are placed in special buildings - astronomical towers. The small towers are rectangular in shape with a flat retractable roof. The towers of large telescopes are usually made round with a hemispherical rotating dome, in which a narrow slit opens for observation. This dome protects the telescope well from the wind during operation. This is important because wind shakes the telescope and causes the image to shake. Vibration of the soil and the tower building also negatively affects the quality of images. Therefore, the telescope is mounted on a separate foundation, not connected to the foundation of the tower. A ventilation system for the under-dome space and an installation for vacuum deposition of a reflective aluminum layer on the telescope mirror, which fades over time, are installed inside the tower or near it. Mount. To point at a star, the telescope must rotate around one or two axes. The first type includes the meridian circle and passage instrument - small telescopes that rotate around a horizontal axis in the plane of the celestial meridian. Moving from east to west, each luminary crosses this plane twice a day. With the help of a passage instrument, the moments of passage of stars through the meridian are determined and thus the speed of rotation of the Earth is clarified; this is necessary for the accurate time service. The meridian circle allows you to measure not only the moments, but also the place where the star intersects the meridian; this is necessary to create accurate star maps. In modern telescopes, direct visual observation is practically not used. They are mainly used to photograph celestial objects or to detect their light with electronic detectors; in this case, the exposure sometimes reaches several hours. All this time, the telescope must be precisely aimed at the object. Therefore, with the help of a clock mechanism, it rotates at a constant speed around the hour axis (parallel to the axis of rotation of the Earth) from east to west following the star, thereby compensating for the rotation of the Earth from west to east. The second axis, perpendicular to the clock axis, is called the declination axis; it serves to point the telescope in the north-south direction. This design is called an equatorial mount and is used for almost all telescopes, with the exception of the largest, for which an alt-azimuth mount turned out to be more compact and cheaper. On it, the telescope monitors the star, turning simultaneously at variable speed around two axes - vertical and horizontal. This significantly complicates the operation of the watch mechanism, requiring computer control. A refracting telescope has a lens objective. Since rays of different colors are refracted differently in glass, the lens lens is designed so that it gives a sharp image in focus in rays of one color. Older refractors were designed for visual observation and therefore produced clear images in yellow light. With the advent of photography, photographic telescopes began to be built - astrographs, which give a clear image in blue rays, which
An observatory is a scientific institution in which employees - scientists of various specialties - observe natural phenomena, analyze observations, and on their basis continue to study what is happening in nature.
Astronomical observatories are especially common: we usually imagine them when we hear this word. They explore stars, planets, large star clusters, and other space objects.
But there are other types of these institutions:
— geophysical - for studying the atmosphere, aurora, the Earth’s magnetosphere, the properties of rocks, the state of the earth’s crust in seismically active regions and other similar issues and objects;
- auroral - for studying the aurora;
— seismic - for constant and detailed recording of all vibrations of the earth’s crust and their study;
— meteorological - to study weather conditions and identify weather patterns;
— cosmic ray observatories and a number of others.
Where are observatories built?
Observatories are built in areas that provide scientists with maximum material for research. 
Meteorological - in all corners of the Earth; astronomical - in the mountains (the air there is clean, dry, not “blinded” by city lighting), radio observatories - at the bottom of deep valleys, inaccessible to artificial radio interference.
Astronomical observatories
Astronomical - the most ancient type of observatories. Astronomers in ancient times were priests; they kept a calendar, studied the movement of the Sun across the sky, and made predictions of events and people’s destinies depending on the position of celestial bodies. These were astrologers - people whom even the most ferocious rulers feared.
Ancient observatories were usually located in the upper rooms of the towers. The tools were a straight bar equipped with a sliding sight.
The great astronomer of antiquity was Ptolemy, who collected a huge number of astronomical evidence and records in the Library of Alexandria, and compiled a catalog of positions and brightness for 1022 stars; invented the mathematical theory of planetary movement and compiled tables of motion - scientists used these tables for more than 1,000 years!
In the Middle Ages, observatories were especially actively built in the East. The giant Samarkand observatory is known, where Ulugbek - a descendant of the legendary Timur-Tamerlane - made observations of the movement of the Sun, describing it with unprecedented accuracy. The observatory with a radius of 40 m had the form of a sextant-trench oriented to the south and decorated with marble.
The greatest astronomer of the European Middle Ages, who turned the world almost literally, was Nicolaus Copernicus, who “moved” the Sun to the center of the universe instead of the Earth and proposed to consider the Earth as another planet.
And one of the most advanced observatories was Uraniborg, or Castle in the Sky, the possession of Tycho Brahe, the Danish court astronomer. The observatory was equipped with the best, most accurate instruments at that time, had its own workshops for making instruments, a chemical laboratory, a storage room for books and documents, and even a printing press for its own needs and a paper mill for producing paper - a royal luxury at that time!
In 1609, the first telescope appeared - the main instrument of any astronomical observatory. Its creator was Galileo. It was a reflecting telescope: the rays in it were refracted, passing through a series of glass lenses.
The Kepler telescope improved: in its instrument the image was inverted, but of higher quality. This feature eventually became standard for telescopic devices.
In the 17th century, with the development of navigation, state observatories began to appear - the Royal Parisian, Royal Greenwich, observatories in Poland, Denmark, Sweden. The revolutionary consequence of their construction and activities was the introduction of a time standard: it was now regulated by light signals, and then by telegraph and radio.
In 1839, the Pulkovo Observatory (St. Petersburg) was opened, which became one of the most famous in the world. Today there are more than 60 observatories in Russia. One of the largest on an international scale is the Pushchino Radio Astronomy Observatory, created in 1956.
The Zvenigorod Observatory (12 km from Zvenigorod) operates the only VAU camera in the world capable of carrying out mass observations of geostationary satellites. In 2014, Moscow State University opened an observatory on Mount Shadzhatmaz (Karachay-Cherkessia), where they installed the largest modern telescope for Russia, with a diameter of 2.5 m.
The best modern foreign observatories
Mauna Kea- located on the Big Hawaiian Island, has the largest arsenal of high-precision equipment on Earth.
VLT complex(“huge telescope”) - located in Chile, in the Atacama “telescope desert”. 
Yerkes Observatory in the United States - “the birthplace of astrophysics.”
ORM Observatory(Canary Islands) - has the optical telescope with the largest aperture (ability to collect light).
Arecibo- is located in Puerto Rico and owns a radio telescope (305 m) with one of the largest apertures in the world.
Tokyo University Observatory(Atacama) - the highest on Earth, located at the top of Mount Cerro Chainantor.
Ways to study outer space
Telescopes from the past to the present day
The desire to penetrate as far as possible into the depths of the Universe and see as many new objects as possible served as an incentive to create more powerful observation instruments. With the advent of telescopes, the first serious problems arose. The fact is that a real optical system is capable of “constructing” an image of a point only in the form of a blurry circle or spot of irregular shape, sometimes colored around the edges; this happens due to errors in the optical system - aberrations. For single-lens telescopes, chromatic aberration is most characteristic, which is due to the fact that the refractive index of glass depends on the wavelength. Therefore, astronomers began to look for ways to eliminate it. It turned out that chromatic aberration can be reduced by using lenses with very long focal lengths. Thus, rather bulky and extremely inconvenient telescopes were born. Time passed, and they were replaced by “air” ones. In them, the lens and eyepiece were mounted almost independently of each other on their own tripods. Such telescopes were used until the middle of the 18th century, although when observing outdoors, especially in windy conditions, such a design did not behave well.
After Johannes Kepler used in the eyepiece not a negative - biconcave - lens, but a positive - biconvex one, it became possible to use eyepieces with a cross of threads and a micrometer. Now telescopes began to be used not only for viewing the sky, but also as measuring instruments. Still, the shortcomings of single-lens refracting telescopes forced scientists to look for new ways. Isaac Newton was one of the first to make a mirror, producing a “mirror” alloy of copper, tin and arsenic. The new telescope with a mirror with a diameter of 30 mm placed in a tube 160 mm long gave a very clear image. This was the first reflector. And although he did not have chromatic aberration, he was not without drawbacks. The main thing was that there were more all other types of aberrations than in the refractor.
The original design of a two-mirror system, consisting of a primary and secondary parabolic mirror, was proposed by the French sculptor and artist Cassegrain. This configuration is very convenient and is widely used today, but in those distant times the idea was not implemented due to the impossibility of obtaining mirrors of the desired shape. In Russia, greater success in the manufacture of metal mirrors was achieved by Ya.V. Bruce, and M.V. Lomonosov developed a new telescope design with an inclined primary mirror without a secondary one, which significantly reduced light loss. The same scheme, independently of him, was used by W. Herschel. In his house, turned into a workshop, he and his brothers obtained a special alloy of copper and tin, and then made mirrors and polished them himself. The pinnacle of his work was a telescope, gigantic at that time, with a main mirror diameter of 122 cm. By the middle of the 18th century, compact, easy-to-use, high-quality reflectors with metal mirrors practically replaced bulky refractors. However, they were far from perfect. Firstly, metal mirrors had a low reflectivity, and their surface faded over time. Secondly, their production was labor-intensive and expensive. Thirdly, large metal mirrors deformed under their own weight. And here successes in glass melting helped a lot. In 1758, two types of glass were obtained: light - crown and heavier - flint, and therefore, it became possible to create two-lens lenses. The Englishman J. Dollond made a lens from positive crown and negative flint lenses and received a patent for the invention of an achromatic lens, that is, free from chromatic aberration. Such lenses, called dollar tubes, quickly became widespread.
The German optician J. Fraunhofer introduced into widespread practice the scientific method of making lens lenses and monitoring their quality. He designed and manufactured first-class achromatic lenses. The crowning achievement of his optical art was the 25-centimeter refractor, bought from him by Russia and installed at the Tartu Observatory. By the middle of the 19th century, Fraunhofer refractors became the main instruments of observational astronomy. It seemed that they had a bright future. But as the spectral range of observations expanded, the main drawback of lens lenses began to appear again - chromatism. A further increase in the diameter of the refractor lens also caused big problems. It was impossible to get uniform large blocks of glass for lenses, and thick lens lenses absorbed too much light. The largest refractor with a lens diameter of 1.02 m was built in 1897, but their further development stopped there.
And then the creators of telescopes again remembered reflectors. In the mid-19th century, the chemical method of silvering glass surfaces became famous. This made it possible to make mirrors from glass. Silver film - the film was applied to a glass mirror by exposing grape sugar to silver nitrate salts. Such mirrors with a fresh silver filter no longer reflected 60% of the incident light, like bronze ones, but from 90 to 95%, which means they were brighter for the same mirror size. Soon L. Foucault developed a method for determining the shape and surface quality of mirrors. Thanks to his research, reflectors with parabolic mirrors appeared.
A new impetus for the further development of telescope construction was the use of aluminized mirrors. They, unlike silver ones, aged more slowly and reflected ultraviolet rays better. At the end of the 19th century, the beginning of the first generation of new reflectors was laid by a wealthy man, an amateur astronomer Crossley, who acquired a concave glass parabolic mirror with a diameter of 91 cm and made a telescope. The next telescope of the same type with a mirror diameter of 1.5 m was installed at the Mount Wilson Observatory. In 1918, a 2.5-meter refractor was built here, and in 1947, a telescope with a 5-meter mirror was put into operation at the Palomar Observatory. And yet, the problems that arose during the creation of this telescope forced specialists to further move towards increasing diameters with more cautious steps. Especially considering that work on large telescopes has shown that a 3-meter diameter using high-quality optics at a point with a calm atmosphere can be much more effective than a 5-meter diameter. Therefore, in the 50s - 80s, 3-4 meter telescopes were mainly built. The only 6-meter one was built in the USSR and installed at the Special Astronomical Observatory in the Caucasus.
In parallel with the development of the optical part, mechanical structures are also being improved, and control of the telescope is entrusted to computers. Now everything is ready to create large telescopes, but due to the lack of sufficient funds, observatories, institutes and even countries are uniting for joint construction. Scientists use the entire available arsenal of telescopes to solve important astronomical questions, such as the origin of planets, stars, the solar system, quasars and active galaxies. Apparently, future developments in telescope construction promise to be truly grandiose. Projects for 50- and 100-meter telescopes are already being proposed, equipped with the most modern receiving and recording equipment capable of providing quality observations that can only be dreamed of today.
Why are they built?
The need to build such telescopes is determined by tasks that require the utmost sensitivity of instruments to detect radiation from the faintest cosmic objects. These tasks include:
- origin of the Universe;
- mechanisms of formation and evolution of stars, galaxies and planetary systems;
- physical properties of matter under extreme astrophysical conditions;
- astrophysical aspects of the origin and existence of life in the Universe.
Currently, the efficiency of receivers in the optical range, understood as the proportion of detected quanta from the total number arriving at the sensitive surface, is approaching the theoretical limit (100%), and further ways of improvement are associated with increasing the format of receivers, accelerating signal processing, etc.
Observation interference is a very serious problem. In addition to natural disturbances (for example, cloudiness, dust formations in the atmosphere), the threat to the existence of optical astronomy as an observational science is posed by increasing illumination from populated areas, industrial centers, communications, and man-made atmospheric pollution. Modern observatories are naturally built in places with a favorable astroclimate. There are very few such places on the globe, no more than a dozen. Unfortunately, there are no places in Russia with a very good astroclimate.
The only promising direction in the development of highly efficient astronomical technology remains an increase in the size of the collecting surfaces of instruments.
Large ground-based optical telescopes - observatories |
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TELESCOPE |
Mirror diameter, m |
Main mirror parameters |
Telescope installation location |
Project participants |
Project cost, million $USD |
First light |
parabolic |
Mauna Kea, Hawaii, USA |
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thin active |
Paranal, Chile |
ESO, cooperation of nine European countries |
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thin active |
Mauna Kea, Hawaii, USA |
USA (25%), England (25%), Canada (15%), Chile (5%), Argentina (2.5%), Brazil (2.5%) |
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thin active |
Mauna Kea, Hawaii, USA |
|||||
cell thick |
Mt. Graham, Arizona, USA |
USA, Italy |
||||
11 (actually 9.5) |
spherical multi-segment |
Mt. Fowlkes, Texac, USA |
USA, Germany |
|||
cell thick |
Mt. Hopkins, Arizona, USA |
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cell thick |
Las Campanas, Chile |
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Mount Pastukhova, Karachay-Cherkessia |
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analogue of KECK II |
La Palma, Canary Islands, Spain |
Spain 51% |
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analog NO |
Sutherland, South Africa |
South Africa |
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35 (actually 28) |
analog NO |
150-200 preliminary project |
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spherical |
Germany, Sweden, Denmark, etc. |
About 1000 preliminary project |
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Projects in excess of huge telescopes, the construction of which will begin soon, are indicated in blue. |
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Large optical telescopes
VLT- a joint project of eight European countries, called the Very Large Telescope. His main idea was to create four telescopes of the same type with a main mirror diameter of 8.2 m and install them in one place with the most favorable astroclimate. Each of them can operate either stand-alone or in combination with other telescopes, in this case providing the collecting ability of a 16-meter telescope. These telescopes have solid mirrors made of a special type of glass, their thickness is only 175 mm, so a complex unloading system was developed especially for them. In the future, these telescopes will operate in interferometer mode to obtain high resolution.
KECK I and KECK II- the first “swallows” of a new generation of large telescopes were two 10-meter twins for optical infrared observations, named “Keck”. They were born thanks to the help of the W. Keck Foundation, which provided $140,000 for their construction. The size of an eight-story building and weighing 300 tons, they work with great precision. At the “heart” of each of them is a main mirror with a diameter of 10 and, consisting of 36 hexagonal segments, working as one reflective mirror. They are installed in one of the best places on Earth for astronomical observations - in Hawaii, on the slope of the extinct volcano Manua Kea 4,200 m high. By 2002, these two telescopes, located at a distance of 85 m from each other, began operating in interferometer mode, giving same angular resolution as an 85 meter telescope. The fact is that a telescope mirror has two characteristics. The first is the light-gathering ability, which is proportional to the area of the mirror, and the second is the ability of the mirror to separate or resolve small objects, called angular resolution and proportional to the diameter of the mirror. If you remove some part from the mirror, its collecting ability will drop sharply, but the angular resolution will remain the same as with the whole mirror. This allows two Keck telescopes to be used like two pieces of a large 85-meter mirror. To improve image quality, this system will be complemented by four more telescopes with a mirror diameter of 1.8 meters.
LBT- unlike a conventional reflector, a binocular telescope has two primary mirrors. Rotating the secondary mirrors makes it possible to quickly switch the telescope from one type of observation to another. The short focal length of the primary mirrors makes it possible to create a compact but fairly rigid structure. The telescope's mechanical system was assembled in Italy and then transported and installed in Arizona. The telescope's mirrors were made at the Mirror Laboratory at the University of Arizona in Tucson from special glass produced in Japan. Once the mirrors are installed and final adjustments are made, the telescope will become part of the Graham International Observatory.
BTA- about 30 years ago in the USSR the 6-m telescope BTA (Large Azimuth Telescope) was built and put into operation. For many years it remained the largest in the world and, naturally, was the pride of domestic science. BTA demonstrated a number of original technical solutions (for example, an alt-azimuth installation with computer guidance), which later became a world technical standard. The BTA is still a powerful tool (especially for spectroscopic studies), but at the beginning of the 21st century. it has already found itself only in the second ten large telescopes in the world. In addition, the gradual degradation of the mirror (now its quality has deteriorated by 30% compared to the original) removes it from being an effective tool. With the collapse of the USSR, the BTA remained practically the only major instrument available to Russian researchers. All observation bases with moderate-sized telescopes in the Caucasus and Central Asia have significantly lost their importance as regular observatories due to a number of geopolitical and economic reasons. Work has now begun to restore connections and structures, but the historical prospects for this process are vague, and in any case, it will take many years only to partially restore what was lost.
Of course, the development of a fleet of large telescopes in the world provides an opportunity for Russian observers to work in the so-called guest mode. Choosing such a passive path would invariably mean that Russian astronomy would always play only secondary (dependent) roles, and the lack of a base for domestic technological developments would lead to a deepening gap, and not only in astronomy. The solution is obvious - a radical modernization of BTA, as well as full participation in international projects.
GEMINI North and GEMINI South- a large international project "Gemini" - two identical telescopes with a main mirror diameter of 8.1 m. They are installed in the Northern and Southern hemispheres of the Earth (respectively in Manua Kea, Hawaii, and Cerro Pachon, Chile) to cover the entire celestial sphere with observations. The primary mirror of each is made from 42 hexagonal blocks made of glass with a very low coefficient of thermal expansion and welded into one thin disk, which is then polished. These telescopes can operate in both the visible and infrared regions of the spectrum. The infrared images will be comparable to, and possibly better than, optical images from the Hubble Space Telescope.
Large radio telescopes
Radio telescopes are usually very large structures. The most common type of radio telescope is a structure whose main element is a solid metal mirror of a parabolic shape. The mirror reflects radio waves incident on it so that they are collected near the focus and captured by a special device - an irradiator. The signal is then amplified and converted into a form convenient for recording and analysis. Data storage and processing are carried out using computer technology. The larger the reflecting surface, the higher the sensitivity of a radio telescope.
An ordinary radio receiver has a device for tuning to the wave of the desired radio station. It is a tunable filter that amplifies radio emissions only on the wavelength of the selected station and does not transmit (suppresses) signals from stations operating on close waves. Unlike earthly radio stations, space radio sources, as a rule, emit in a wide range of radio waves. Therefore, a radio astronomy receiver should have sensitivity over the widest possible range. Such a receiver is called a radiometer.
The expansion of the reception band is mainly hampered by interference from terrestrial radio stations. Therefore, for radio astronomy, international agreements have allocated special wavelength intervals that are prohibited from using by any ground-based radio equipment.
Arecibo- the world's largest 300-meter radio telescope with a parabolic antenna was built in 1963 in Arecibo, on the island of Puerto Rico. It is designed, built and operated by the US National Astronomical and Ionospheric Research Center. The telescope is located in a huge natural pit in the mountains. At a height of 150 m above the surface of the giant fixed mirror, a 600-ton platform is mounted on steel cables, which can be reached via a half-kilometer suspension bridge or by cable car. The moving part of the platform rotates around its own axis. A computer-controlled cabin with irradiators and receivers moves along rails along the platform - this is how the radio telescope is aimed at the source under study. Due to the immobility of the antenna, observations of any source cannot last more than two hours. But this disadvantage is compensated by the huge mirror area, which provides high sensitivity. The Arecibo radio telescope also differs from many others in that it can also serve as a transmitting antenna. In this mode, unique experiments on radar of the Sun, Moon and planets of the Solar System were carried out.
Effelsberg- In 1972, a 100-meter fully rotating radio telescope was built in Germany. It was built in a gorge of low mountains 50 km from Bonn, near the small town of Effelsberg. The radio telescope has a fairly high surface accuracy, which allows it to be used even at a wavelength of 4 mm. The angular resolution of the telescope at such a short wavelength is about 10". This radio telescope is still considered the world's largest fully rotating radio telescope.
There are only one radio telescope with a mirror diameter greater than 50 m. The second largest in Europe after Effelsberg is the 76-meter radio telescope at Jodrell Bank Observatory. It is effectively used only in the decimeter wavelength range, since the accuracy of the mirror surface is not very high.
RATAN-600- in 1994, a 64-meter radio telescope, the third largest in Europe, began operating in Russia. It is located near the city of Kalyazin on the Volga, 180 km north of Moscow. A large domestic radio telescope is RATAN-600 (Radio Telescope of the Academy of Sciences with a diameter of 600 m), built in 1976 in the North Caucasus, near the village of Zelenchukskaya. The mirror of this telescope does not cover the entire area of the circle, but is a ring with a diameter of 600 m, assembled from 895 aluminum shields 7 m high. The angular resolution of such a system is determined by the diameter of the ring and is about 10 at a wavelength of 3 cm. In real observations, the entire ring is rarely used at once. The telescope is divided into sectors: northern, southern, eastern and western. The shields of each sector are oriented towards the selected source, and in focus Each sector has an irradiator that can move, providing observations of a given source for several minutes.
So far, radio telescopes have been considered in which all the energy of radio waves is focused using a mirror or a system of mirrors onto a common feed source and then amplified by one receiver. There is another type of radio telescope: the radiation is received by independent antennas, amplified at each antenna and transmitted through cables or waveguides to combine the signal. The length of the cables is selected so that the signals from all antennas arrive at the summing device in the same phase. This ensures electrical focusing of the entire antenna system. Such radio telescopes are called in-phase antennas. At the FIAN radio astronomy station in the city of Pushkino, Moscow region, there is a Large In-Phase Antenna (BSA), which is a field of interconnected dipole antennas 300 m long and 400 m wide. The effective collecting area of the BSA is almost the same as that of the Arecibo radio telescope. The BSA operates at a wavelength of 3 m. This radio telescope primarily studies pulsars and galactic nuclei.
