an institution where scientists observe, study and analyze natural phenomena. The most famous are astronomical observatories for the study of stars, galaxies, planets and other celestial objects. There are also meteorological observatories for observing the weather; geophysical observatories for studying atmospheric phenomena, in particular, auroras; seismic stations for recording vibrations generated in the Earth by earthquakes and volcanoes; observatories for observing cosmic rays and neutrinos. Many observatories are equipped not only with serial instruments for recording natural phenomena, but also with unique instruments that provide the highest possible sensitivity and accuracy under specific observation conditions. In the old days, observatories, as a rule, were built near universities, but then they began to be placed in places with the best conditions for observing the phenomena under study: seismic observatories - on the slopes of volcanoes, meteorological - evenly across the globe, auroral (for observing auroras) - at a distance of about 2000 km from the magnetic pole of the Northern Hemisphere, where the band of intense auroras passes. Astronomical observatories, which use optical telescopes to analyze light from space sources, require a clean, dry atmosphere, free from artificial lighting, so they try to build them high in the mountains. Radio observatories are often located in deep valleys, closed on all sides by mountains from artificial radio interference. Nevertheless, since the observatories employ qualified personnel and scientists regularly visit, whenever possible they try to locate the observatories not very far from scientific and cultural centers and transport hubs. However, the development of communication means makes this problem less and less urgent. This article is about astronomical observatories. Additional information about observatories and scientific stations of other types is described in the articles:
EXTRA ATMOSPHERIC ASTRONOMY;
VOLCANOES;
GEOLOGY;
EARTHQUAKES;
METEOROLOGY AND CLIMATOLOGY;
NEUTRINAL ASTRONOMY;
RADAR ASTRONOMY;
RADIOASTRONOMY.
HISTORY OF ASTRONOMIC OBSERVATORIES AND TELESCOPES
Ancient world. The oldest extant facts of astronomical observations are associated with the ancient civilizations of the Middle East. Observing, recording and analyzing the movement of the Sun and the Moon across the sky, the priests kept track of time and calendar, predicted important seasons for agriculture, and also engaged in astrological forecasts. Measuring the movements of celestial bodies with the help of the simplest instruments, they found that the relative position of the stars in the sky remains unchanged, and the Sun, Moon and planets move relative to the stars and, moreover, it is very difficult. The priests noted rare celestial phenomena: lunar and solar eclipses, the appearance of comets and new stars. Astronomical observations, which bring practical benefits and help shape the worldview, found some support both among religious authorities and civil rulers of different nations. Astronomical observations and calculations are recorded on many surviving clay tablets from ancient Babylon and Sumer. In those days, as now, the observatory served simultaneously as a workshop, instrument storage and data collection center. see also
ASTROLOGY;
SEASONS;
TIME;
CALENDAR. Little is known about astronomical instruments used prior to Ptolemy (c. 100 - c. 170 CE). Ptolemy, along with other scientists, collected in the huge library of Alexandria (Egypt) many scattered astronomical records made in various countries over the previous centuries. Using Hipparchus's observations and his own, Ptolemy compiled a catalog of the positions and brightness of 1,022 stars. Following Aristotle, he placed the Earth at the center of the world and believed that all the luminaries revolve around it. Together with his colleagues, Ptolemy conducted systematic observations of moving luminaries (Sun, Moon, Mercury, Venus, Mars, Jupiter, Saturn) and developed a detailed mathematical theory to predict their future position in relation to "fixed" stars. With its help, Ptolemy calculated tables of the motion of the luminaries, which were then used for more than a thousand years.
see also HIPPARCH. To measure the slightly changing sizes of the Sun and Moon, astronomers used a straight bar with a sliding sight in the form of a dark disk or a plate with a round hole. The observer directed the bar at the target and moved the sight along it, achieving an exact match of the hole with the size of the luminary. Ptolemy and his colleagues improved many of the astronomical instruments. Carrying out careful observations with them and using trigonometry translating the instrumental readings into positional angles, they brought the measurement accuracy to about 10 "
(see also POTOLEMY Claudius).
Middle Ages. Due to the political and social upheavals of late antiquity and the early Middle Ages, the development of astronomy in the Mediterranean has stalled. Ptolemy's catalogs and tables survived, but fewer and fewer people knew how to use them, and less and less observations and registration of astronomical events were carried out. However, in the Middle East and Central Asia, astronomy flourished and observatories were built. In the 8th century. Abdullah al-Mamun founded the House of Wisdom in Baghdad, similar to the Library of Alexandria, and set up associated observatories in Baghdad and Syria. There, several generations of astronomers studied and developed the work of Ptolemy. Similar institutions flourished in the 10th and 11th centuries. in Cairo. The culmination of that era was the giant observatory in Samarkand (now Uzbekistan). There Ulukbek (1394-1449), the grandson of the Asian conqueror Tamerlane (Timur), built a huge sextant with a radius of 40 m in the form of a south-facing trench 51 cm wide with marble walls, and carried out observations of the Sun with unprecedented accuracy. He used several smaller instruments to observe stars, the moon, and planets.
Revival. When in the Islamic culture of the 15th century. astronomy flourished, Western Europe rediscovered this great creation of the ancient world.
Copernicus. Nicolaus Copernicus (1473-1543), inspired by the simplicity of the principles of Plato and other Greek philosophers, looked with disbelief and dismay at Ptolemy's geocentric system, which required cumbersome mathematical calculations to explain the apparent movements of the luminaries. Copernicus proposed, keeping the approach of Ptolemy, to place the Sun in the center of the system, and the Earth to be considered a planet. This greatly simplified the matter, but caused a deep revolution in the consciousness of people (see also KOPERNIK Nikolay).
Tycho Brahe. The Danish astronomer T. Brahe (1546-1601) was discouraged by the fact that Copernicus' theory predicted the position of the luminaries more accurately than Ptolemy's theory, but still not entirely true. He considered that more accurate observational data would solve the problem, and persuaded King Frederick II to give him for the construction of the observatory about. Ven near Copenhagen. This observatory, called Uraniborg (Sky Castle), contained many stationary instruments, workshops, a library, a chemistry laboratory, bedrooms, a dining room, and a kitchen. Tycho even had his own paper mill and printing press. In 1584 he built a new observation building - Stjerneborg (Star Castle), where he collected the largest and most sophisticated instruments. True, these were devices of the same type as in the time of Ptolemy, but Tycho significantly increased their accuracy, replacing wood with metals. He introduced especially accurate sighting lines and scales, and invented mathematical methods for calibrating observations. Tycho and his assistants, observing celestial bodies with the naked eye, achieved with their instruments a measurement accuracy of 1 ". They systematically measured the positions of the stars and observed the movement of the Sun, Moon and planets, collecting observational data with unprecedented persistence and accuracy.
(see also BRAGUE Tycho).

Kepler. Studying Tycho's data, I. Kepler (1571-1630) found that the observed revolution of the planets around the Sun cannot be represented as movement in circles. Kepler had great respect for the results obtained at Uraniborg, and therefore rejected the idea that small discrepancies between the calculated and observed positions of the planets could be caused by errors in Tycho's observations. Continuing the search, Kepler established that the planets move in ellipses, thus laying the foundation for a new astronomy and physics.
(see also KEPLER Johann; KEPLER'S LAWS). The work of Tycho and Kepler anticipated many features of modern astronomy, such as the organization of specialized observatories with government support; bringing to perfection devices, even traditional ones; division of scientists into observers and theorists. New principles of work were approved along with new technology: a telescope was used to help the eye in astronomy.
The emergence of telescopes. The first refractor telescopes. In 1609 Galileo began using his first homemade telescope. Galileo's observations ushered in the era of visual studies of celestial bodies. Telescopes soon spread throughout Europe. Curious people made them themselves or ordered them from craftsmen and set up small personal observatories, usually in their own homes.
(see also GALILEY Galileo). Galileo's telescope was called a refractor because the rays of light in it are refracted (Latin refractus - refracted), passing through several glass lenses. In the simplest design, the front lens-objective collects rays in focus, creating an image of the object there, and the lens-eyepiece located near the eye is used as a magnifying glass to examine this image. In the Galileo telescope, a negative lens served as an eyepiece, giving a direct image of a rather low quality with a small field of view. Kepler and Descartes developed the theory of optics, and Kepler proposed an inverted telescope design, but with a significantly larger field of view and magnification than Galileo's. This design quickly replaced the previous one and became the standard for astronomical telescopes. For example, in 1647 the Polish astronomer Jan Hevelius (1611-1687) used Keplerian telescopes 2.5-3.5 meters long to observe the Moon. Initially, he installed them in a small turret on the roof of his house in Gdansk (Poland), and later on a platform with two observation posts, one of which was rotating (see also GEWELIJAN). In Holland, Christian Huygens (1629-1695) and his brother Constantine built very long telescopes, which had lenses only a few inches in diameter, but had a huge focal length. This improved the image quality, although it made the instrument more difficult to operate. In the 1680s Huygens experimented with 37-meter and 64-meter "air telescopes", the lenses of which were placed at the top of the mast and rotated with a long stick or ropes, and the eyepiece was simply held by hand (see also HUYGENS Christian). Using lenses made by D. Campani, J.D. Cassini (1625-1712) in Bologna and later in Paris carried out observations with air telescopes 30 and 41 m long, demonstrating their undoubted advantages, despite the difficulty of working with them. Observations were greatly hampered by the vibration of the mast with the lens, the difficulty of pointing it with ropes and cables, as well as the inhomogeneity and turbulence of the air between the lens and the eyepiece, which was especially strong in the absence of a tube. Newton, the reflector telescope and the theory of gravitation. In the late 1660s, I. Newton (1643-1727) tried to unravel the nature of light in connection with the problems of refractors. He mistakenly decided that chromatic aberration, i.e. the inability of the lens to collect rays of all colors in one focus is fundamentally unavoidable. Therefore, Newton built the first functional reflector telescope, in which a concave mirror played the role of an objective instead of a lens, collecting light in focus, where the image can be viewed through an eyepiece. However, Newton's most important contribution to astronomy was his theoretical work, which showed that Keplerian laws of planetary motion are a special case of the universal law of gravitation. Newton formulated this law and developed mathematical techniques to accurately calculate the motion of the planets. This stimulated the birth of new observatories, where the positions of the Moon, planets and their satellites were measured with the highest accuracy, refining the elements of their orbits with the help of Newton's theory and predicting their movement.
see also
HEAVENLY MECHANICS;
GRAVITY;
NEWTON ISAAC.
Clock, micrometer and telescopic sight. No less important than the improvement of the optical part of the telescope was the improvement of its mount and equipment. For astronomical measurements, a pendulum clock capable of running according to local time, which is determined from some observations and used in others, has become necessary.
(see also CLOCK). With the help of a filament micrometer, it was possible to measure very small angles when observing through the eyepiece of a telescope. To increase the accuracy of astrometry, the combination of the telescope with an armillary sphere, sextant and other goniometric instruments played an important role. As soon as sighting devices for the naked eye were supplanted by small telescopes, the need arose for much more accurate manufacturing and division of angular scales. To a large extent in connection with the needs of European observatories, the production of small high-precision machine tools has developed
(see also MEASURING TOOLS).
State observatories. Improvement of astronomical tables. From the second half of the 17th century. for the purposes of navigation and cartography, governments of different countries began to establish state observatories. At the Royal Academy of Sciences, founded by Louis XIV in Paris in 1666, academics set about revising astronomical constants and tables from scratch, taking Kepler's work as the basis. In 1669 the Royal Observatory in Paris was founded on the initiative of the minister Jean-B. Colbert. It was led by four remarkable generations of Cassini, beginning with Jean Dominique. In 1675, the Royal Greenwich Observatory was founded, headed by the first Astronomer Royal D. Flamsteed (1646-1719). Together with the Royal Society, which began its activity in 1647, it became the center of astronomical and geodetic research in England. In the same years, observatories were founded in Copenhagen (Denmark), Lund (Sweden) and Gdansk (Poland) (see also FLEMSTED John). The most important result of the activities of the first observatories were ephemerides - tables of the pre-calculated positions of the Sun, Moon and planets, necessary for cartography, navigation and fundamental astronomical research.
Introduction of standard time. State observatories became the keepers of the reference time, which was first disseminated using optical signals (flags, signal balls), and later by telegraph and radio. The current tradition of balloons falling at midnight on Christmas Eve dates back to the days when signal balloons fell on the high mast on the roof of the observatory at exactly the appointed time, allowing the captains of ships in the harbor to check their chronometers before sailing.
Determination of longitudes. An extremely important task of the state observatories of that era was to determine the coordinates of ships. Geographic latitude is easy to find by the angle of the North Star above the horizon. But longitude is much more difficult to determine. Some methods were based on the moments of eclipses of Jupiter's moons; others - on the position of the moon relative to the stars. But the most reliable methods required high-precision chronometers capable of keeping the time of the observatory near the port of exit during the voyage.
Development of the Greenwich and Paris Observatories. In the 19th century. the most important astronomical centers were state and some private observatories in Europe. In the list of observatories from 1886, we find 150 in Europe, 42 in North America, and 29 elsewhere. By the end of the century, the Greenwich Observatory had a 76-cm ​​reflector, 71-, 66- and 33-cm refractors and many auxiliary instruments. She was actively engaged in astrometry, time service, solar physics and astrophysics, as well as geodesy, meteorology, magnetic and other observations. The Paris Observatory also possessed precise modern instruments and conducted programs similar to those of Greenwich.
New observatories. The Pulkovo Astronomical Observatory of the Imperial Academy of Sciences in St. Petersburg, built in 1839, quickly gained respect and honor. Her growing team focused on astrometry, fundamental constants, spectroscopy, timing, and a variety of geophysical programs. The Potsdam Observatory in Germany, opened in 1874, soon became a reputable organization known for its work on solar physics, astrophysics, and photographic sky surveys.
Creation of large telescopes. Reflector or Refractor? Although the Newtonian reflector telescope was an important invention, for several decades it was perceived by astronomers only as a tool to complement refractors. In the beginning, the reflectors were made by the observers themselves for their own small observatories. But by the end of the 18th century. a fledgling optical industry took over, assessing the need for a growing number of astronomers and surveyors. Observers were able to choose from a variety of reflector and refractor types, each with advantages and disadvantages. Refractor telescopes with high-quality glass lenses gave better images than reflectors, and their tube was more compact and stiffer. But reflectors could be made of a much larger diameter, and the images in them were not distorted by colored borders, as in refractors. Faint objects are better seen in the reflector, since there is no loss of light in the glasses. However, the speculum alloy, from which the mirrors were made, quickly faded and required frequent re-polishing (they did not know how to cover the surface with a thin mirror layer at that time).
Herschel. In the 1770s, the meticulous and persistent self-taught astronomer V. Herschel built several Newtonian telescopes, bringing the diameter to 46 cm and the focal length to 6 m. The high quality of his mirrors made it possible to apply very strong magnification. Using one of his telescopes, Herschel discovered the planet Uranus, as well as thousands of double stars and nebulae. Many telescopes were built in those years, but they were usually created and used by solo enthusiasts, without organizing an observatory in the modern sense.
(see also GERSHEL, WILLIAM). Herschel and other astronomers have tried to build larger reflectors. But the massive mirrors bent and lost their shape when the telescope changed position. The limit for metal mirrors was reached in Ireland by W. Parsons (Lord Ross), who created a reflector with a diameter of 1.8 m for his home observatory.
Construction of large telescopes. The industrial magnates and nouveau riche of the United States accumulated at the end of the 19th century. gigantic riches, and some of them were engaged in philanthropy. Thus, J. Lick (1796-1876), who made his fortune on the gold rush, bequeathed to establish an observatory on Mount Hamilton, 65 km from Santa Cruz (California). Its main instrument was the 91-cm refractor, then the largest in the world, manufactured by the well-known company "Alvan Clark and Sons" and installed in 1888. And in 1896, at the same place, at the Lick Observatory, the 36-inch Crossley reflector, then the largest in the United States, began to work. ... Astronomer J. Hale (1868-1938) persuaded Chicago tram tycoon Ch. Yerkes to finance the construction of an even larger observatory for the University of Chicago. It was founded in 1895 in Williams Bay, Wisconsin, equipped with a 40-inch refractor, still and probably forever the largest in the world (see also HALE George Ellery). With the establishment of the Yerkes Observatory, Hale has developed a vigorous effort to raise funds from various sources, including the steel tycoon A. Carnegie, to build an observatory in the best observing location in California. Equipped with several Hale solar telescopes and a 152-cm reflector, Mount Wilson Observatory in the San Gabriel Mountains north of Pasadena, California, soon became an astronomical mecca. With the necessary experience, Hale orchestrated the creation of a reflector of unprecedented size. Named after its main sponsor, the Hooker entered service in 1917; but before that, many engineering problems had to be overcome, which at first seemed insurmountable. The first was casting a glass disc of the correct size and cooling it slowly to obtain high quality glass. It took more than six years to grind and polish the mirror to give it the required shape and required the creation of unique machines. The final stage of mirror polishing and inspection was carried out in a special room with perfect cleanliness and temperature control. The mechanisms of the telescope, the building and the dome of its tower, erected on the top of Mount Wilson (Mount Wilson) with a height of 1700 m, were considered an engineering marvel of that time. Inspired by the excellent performance of the 100 "instrument, Hale devoted the rest of his life to building a giant 200" telescope. 10 years after his death and due to the delay caused by the Second World War, the telescope. Hale entered service in 1948 at the summit of the 1,700-meter Palomar Mountain (Mount Palomar), 64 km northeast of San Diego (pcs. California). It was a scientific and technical miracle of those days. For nearly 30 years, this telescope remained the largest in the world, and many astronomers and engineers believed that it would never be surpassed.

But the advent of computers further expanded the construction of telescopes. In 1976, the 6-meter BTA telescope (Large azimuth telescope) began operating on the 2100-meter Semirodniki mountain near the village of Zelenchukskaya (North Caucasus, Russia), demonstrating the practical limit of the "thick and durable" mirror technology.

The way to build large mirrors that can collect more light, and therefore see farther and better, lies through new technologies: in recent years, methods of making thin and prefabricated mirrors have been developing. Thin mirrors 8.2 m in diameter (with a thickness of about 20 cm) are already operating at the telescopes of the Southern Observatory in Chile. Their shape is controlled by a complex system of mechanical "fingers" controlled by a computer. The success of this technology has led to the development of several similar projects in different countries. To test the idea of ​​a composite mirror, the Smithsonian Astrophysical Observatory built a telescope in 1979 with a lens of six 183-cm mirrors, the area equivalent to one 4.5-meter mirror. This multi-mirror telescope, mounted on Mount Hopkins, 50 km south of Tucson, Arizona, has proven to be very effective, and this approach was used in the construction of two 10-meter telescopes. W. Keck at the Mauna Kea Observatory (Hawaii). Each giant mirror is composed of 36 hexagonal segments 183 cm across, controlled by a computer to produce a single image. Although the image quality is still low, it is possible to obtain spectra of very distant and faint objects inaccessible to other telescopes. Therefore, in the early 2000s, it is planned to commission several more multi-mirror telescopes with effective apertures of 9-25 m.

AT THE TOP OF MAUNA KEA, an ancient volcano in Hawaii, dozens of telescopes are located. Astronomers are attracted here by its high altitude and very dry, clean air. At the bottom right, through the open slit of the tower, the mirror of the "Kek I" telescope is clearly visible, and at the bottom left - the tower of the "Kek II" telescope under construction.

DEVELOPMENT OF EQUIPMENT
The photo. In the middle of the 19th century. several enthusiasts began to use photography to record images seen through a telescope. With the increase in the sensitivity of emulsions, glass photographic plates became the main means of recording astrophysical data. In addition to traditional handwritten observation journals, precious "glass libraries" have appeared in observatories. The photographic plate is capable of accumulating the weak light of distant objects and fixing details inaccessible to the eye. With the use of photography in astronomy, new types of telescopes were required, for example, wide-view cameras, capable of registering large areas of the sky at once to create photoatlases instead of drawn maps. In combination with large-diameter reflectors, photography and a spectrograph made it possible to study faint objects. In the 1920s, using the 100-inch telescope of the Mount Wilson Observatory, E. Hubble (1889-1953) classified faint nebulae and proved that many of them are giant galaxies like the Milky Way. In addition, Hubble discovered that galaxies are rapidly scattering from each other. This completely changed the idea of ​​astronomers about the structure and evolution of the Universe, but only a few observatories that had powerful telescopes for observing faint distant galaxies were able to carry out such studies.
see also
COSMOLOGY;
GALAXIES;
HUBBL Edwin Powell;
FOGS.
Spectroscopy. Appearing almost simultaneously with photography, spectroscopy allowed astronomers to determine their chemical composition from the analysis of light from stars, and from the Doppler shift of lines in the spectra to study the motion of stars and galaxies. The development of physics at the beginning of the 20th century. helped to decipher the spectrograms. For the first time, it became possible to study the composition of inaccessible celestial bodies. This task turned out to be within the power of modest university observatories, since a large telescope is not needed to obtain spectra of bright objects. Thus, the Harvard College Observatory was one of the first to take up spectroscopy and collected a huge collection of stellar spectra. Its employees have classified thousands of stellar spectra and created a basis for studying stellar evolution. By combining this data with quantum physics, theorists understood the nature of the source of stellar energy. In the 20th century. detectors were created for infrared radiation coming from cold stars, from the atmospheres and from the surface of planets. Visual observations as an insufficiently sensitive and objective measure of the brightness of stars were first supplanted by a photographic plate, and then by electronic devices (see also SPECTROSCOPY).
ASTRONOMY AFTER WORLD WAR II
Strengthening government support. After the war, scientists became available to new technologies that were born in army laboratories: radio and radar equipment, sensitive electronic light receivers, computers. The governments of industrialized countries realized the importance of scientific research for national security and began to allocate considerable funds for scientific work and education.
US National Observatories. In the early 1950s, the US National Science Foundation approached astronomers for proposals for a nationwide observatory that would be in the best location and accessible to all qualified scientists. By the 1960s, two groups of organizations emerged: the Association of Universities for Research in Astronomy (AURA), which created the concept of the National Optical Astronomy Observatories (NOAO) at the 2100-meter summit of Kitt Peak near Tucson, Arizona, and the Universities Association, which developed the project The National Radio Astronomy Observatory (NRAO) in Deer Creek Valley, near Green Bank, West Virginia.

US NATIONAL OBSERVATORY KITT PEAK near Tucson, Arizona. Its largest instruments include the McMas Solar Telescope (bottom), the Mayol 4-meter telescope (top right) and the WIYN 3.5-meter telescope at the Joint Observatory of Wisconsin, Indiana, Yale and NOAO (far left).

By 1990, NOAO had 15 telescopes at Kitt Peak with a diameter of up to 4 m. AURA also established the Inter-American Observatory in the Sierra Tololo (Chilean Andes) at an altitude of 2200 m, where the southern sky has been studied since 1967. In addition to Green Bank, where the largest radio telescope (43 m in diameter) is installed on an equatorial mount, NRAO also has a 12-meter millimeter-wave telescope at Kitt Peak and a Very Large Array (VLA) system of 27 radio telescopes 25 m in diameter on the desert San Plain. -Augustin near Socorro, New Mexico. The National Radio and Ionosphere Center in Puerto Rico became a major American observatory. Its radio telescope with the world's largest spherical mirror 305 m in diameter lies motionless in a natural depression among the mountains and is used for radio and radar astronomy.

The permanent staff of the national observatories monitor the health of the equipment, develop new instruments and carry out their own research programs. However, any scientist can apply for observations and, if approved by the Research Coordination Committee, get time to work on the telescope. This allows scientists from poorer institutions to use the most sophisticated equipment.
Observations of the southern sky. Much of the southern sky is not visible from most observatories in Europe and the United States, although it is the southern sky that is considered particularly valuable for astronomy, as it contains the center of the Milky Way and many important galaxies, including the Magellanic Clouds, two small neighboring galaxies. The first maps of the southern sky were compiled by the English astronomer E. Galley, 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 Longitudes 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 various programs. In 1869, a 122 cm reflector was installed in Melbourne (Australia); later it was transported to Mount Stromlo, where, after 1905, an astrophysical observatory began to grow. At the end of the 20th century, when conditions for observations at old observatories in the Northern Hemisphere began to deteriorate due to strong urbanization, European countries began to actively build observatories with large telescopes in Chile, Australia, Central Asia, the Canary Islands and Hawaii.
Observatories over the Earth. Astronomers began using high-altitude balloons as observation platforms back in the 1930s and continue such studies to this day. In the 1950s, instruments were installed on high-altitude aircraft that became flying observatories. Extra-atmospheric observations began in 1946, when US scientists on captured German V-2 rockets raised detectors into the stratosphere to observe the ultraviolet radiation of the Sun. The first artificial satellite was launched in the USSR on October 4, 1957, and already in 1958 the Soviet station "Luna-3" photographed the far side of the moon. Then flights to the planets began to be carried out and specialized astronomical satellites appeared for observing 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 ranges of the spectrum.
Work at the observatory. In earlier times, the life and work of an astronomer was entirely dependent 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 strove to ensure that Mount Wilson had everything he needed to live and work, just as Tycho did on the island of Ven. Until now, some of the large observatories on the mountain peaks are closed communities of scientists and engineers who live in dormitories and work at night on 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

• - a scientific institution equipped with TELESCOPES and other equipment for astronomical observations ...

  Scientific and technical encyclopedic dictionary

• - an institution where scientists observe, study and analyze natural phenomena ...

  Collier's Encyclopedia

• - specialized scientific. institution equipped for astr., physical., meteorol. etc. research ...

Galileo's telescope revolutionized astronomy. In those days, nothing was known about the existence of galaxies, and scientists were arguing about whether the Earth is the center of the universe. And the majority believed that it is, and the Sun, planets and even stars - all space objects revolve around our planet.

Galileo Galilei telescope

Using a telescope, Galileo made a number of discoveries that expanded the horizons of knowledge. First, he became convinced that the Milky Way is a countless cluster of incredibly distant stars. And then astronomers realized that the universe is much more complicated than they imagined.

Secondly, Galileo discovered a complex relief on the lunar surface: mountains, hollows, circuses and other irregularities. This spoke of the great similarity between the Earth and other celestial bodies. The Earth is not the center of the Universe, it is similar in appearance to other cosmic objects: there are also rocks, plains and ravines on celestial bodies.

Third, Galileo discovered four giant moons of Jupiter, later named Io, Ganymede, Europa, and Callisto (see Chapter 3). The scientist observed their orbital motion and came to the conclusion that this is exactly what the solar system looks like from the side. The Jupiter family served as a reduced model of the universe: the "king of the planets" played the role of the Sun, and his satellites - the planets, including the Earth.

After this historical discovery, astronomy gradually abandoned the theory of the Earth as the center of the Universe. And after about half a century, the French physicist Blaise Pascal (1623-1662) declared the infinity of the Universe and the absence of its center.

People who are not involved in astronomy believe that the telescope "brings" distant objects closer to observers. What does he really do? It turns out that an optical telescope does not zoom in or even magnify anything. Its main purpose is to collect as much radiant energy as possible - just like in the human eye.

The possibilities of the eye are limited by its modest size. For example, our pupil diameter is at most 7 mm. It is clear that with such a size, the eye is not able to accommodate a lot of light. Distant and dim luminaries become invisible to us. But what if you enlarge the eye up to a meter across and make its pupil about 20 cm in diameter? But these are the dimensions that small telescopes have. Even Galileo's relatively primitive telescope collected 144 times more light than the human eye.

The telescope collects much more light and therefore increases brightness(shine) dim objects. Correctly measured brightness helps to accurately establish the luminosity and color of celestial bodies. In addition, a powerful telescope makes it possible to obtain detailed spectra of luminaries and to carry out other important measurements by which scientists judge the nature of stars, planets and small objects.

Another advantage of the telescope over the eye is that it has a high resolution, which is incorrectly called "magnification". In fact, resolution is the ability to distinguish between two distant objects located close to each other. The discovery of binary stars is a typical example of the superiority of telescopic observation. In binary systems, the components are indistinguishable to the naked eye. The telescope does not "bring closer" the double star, but it allows you to clearly see each of its components separately.

A modern optical telescope is a complex technical structure of enormous size and colossal mass. Let's say the weight of the Zelenchuk telescope is 850 tons. The huge structure is set in motion by a clock mechanism, the motors of which turn the telescope. Naturally, it is impossible to keep such a structure in the open air on any props. This is why special buildings are built to house telescopes - astronomical observatories .

Word observatory means in translation from the Latin language "a place for observation". Apart from astronomical observatories, there are other observatories, for example, geophysical ones, where the "pulse" of the planet is monitored for many years: its gravity, magnetic field, tremors, etc.

Pulkovo Astronomical Observatory

There are more than 20 large astronomical observatories in our country. The main one is Pulkovskaya, located near St. Petersburg.

Since observations require a clean, dust-free sky, quite often they try to build observatories in mountainous areas located at altitudes of 500 m above sea level and above. In our country, eight observatories have been erected in the mountains. Most of the high-altitude observation points are concentrated in the Caucasus, and there are also two observatories that are higher than all the others in Russia. Firstly, this is the Special Astrophysical (or Zelenchukskaya) Observatory, located on Mount Semirodniki in Karachay-Cherkessia. Secondly, this is the Caucasian Mountain Observatory on the Shatdzhatmaz plateau in the same Karachay-Cherkessia. Both are located at 2100 m above sea level.

In addition to the Caucasus, there are high-altitude observatories in the mountains of Southern Siberia, and the Sayan observatory of the Academy of Sciences in the village of Mondy (elevation 2000 m) is located above all of these observation points.

Earlier, it was about ground-based observatories, but with the beginning of the space age, people did not abandon their attempts to put scientific equipment into space in order to conduct research without interference with the earth's atmosphere. Over the past 40 years, a lot of people have worked and are still working outside the Earth. orbital observatories equipped with specially designed space telescopes. The most famous orbiting observatory is the Hubble Space Telescope.

Hubble Orbital Telescope

Despite the variety of ground-based and space telescopes, all of them are divided into two main classes in terms of their design: refractors and reflectors - depending on whether lenses or mirrors are used to collect light. Galileo's first optical telescope was a typical refractor. Subsequently, Galileo's invention was improved by the German astronomer Johannes Kepler, which is why all modern refractors (and at the same time telescopes and binoculars) are variants of the "Kepler tube".

Refractor called a telescope in which the collection of radiation from space sources is carried out using several lenses. The name of the telescope means "refractive" because the action of lenses is to refract light rays. Today, refractors are made using not two, but a much larger number of glasses. Nevertheless, such a telescope invariably has two components - a lens and an eyepiece.

Lens Is a group of lenses designed to receive light. That is, it is the part of the telescope aimed at the object (hence its name).

Eyepiece(from latin oculus- "eye") is a system of lenses that transfer an image to the observer's eye. The astronomer looks through the eyepiece while working, and the lens aims at a pre-designated area of ​​the sky.

Lenses differ in visual and photographic. Visual consist of lenses that collect mainly yellow and green rays. These rays are best perceived by the human eye, so the task of a visual telescope is to create a highly visible image. Lenses photographic lens are designed to collect mainly blue and violet rays, to which the photographic plate is sensitive. Such a lens makes it possible to obtain high-quality photographs of space bodies.

How the refractor works

Visual lenses are currently almost never used; they are installed mainly on school and amateur telescopes. Refractors for professional scientific work are equipped with photographic lenses so that scientists can take pictures of the starry sky.

The most important parameter of the lens is its diameter... The larger the diameter of the largest objective lens, the more light the instrument can capture. The world's largest refractor, built in 1897 at the Yerkes Observatory (USA), has a lens with a diameter of 102 cm.

According to the degree of brightness, celestial bodies are characterized by the so-called apparent magnitude... Apparent stellar magnitude (or simply stellar magnitude) is the eye-distinguishable difference in the brightness of point lights in the sky. The first to measure the brightness of the stars was the ancient Greek astronomer Hipparchus, who lived in the II century BC. NS.

Yerkes Observatory Refractor

Hipparchus allocated six magnitudes for his catalog. In this case, the brightness of a star of the first magnitude (the brightest) is about 2.5 times brighter than the brightness of a star of the second magnitude. And the brightness of a second-magnitude star is 2.5 times brighter than the brightness of a third-magnitude star, etc. Today, astronomers have improved the way to measure visible magnitudes, and zero magnitude is taken as the starting point, which corresponds to the brightness of such bright stars as Vega and Arcturus.

Table 5

The brilliance of some stars with exoplanets

More than 400 years have passed since the great Italian Galileo Galilei assembled his first telescope. The telescope of those days was a small refractor with a lens diameter of only 4 centimeters, which did not prevent him from making many major discoveries.

Chinese 500-meter telescope FAST

A century and a half ago, most of the observatories were built right in cities, mainly at large universities. With the advent of electric lighting, the problem arose of illuminating the night sky, in connection with which we had to look for deserted places.

Today, much has changed and now astronomical observations require not only large instruments, but also solid funding. This is not just a costly business; it requires the developer to use high technologies that are not available in every country. The period from design work to completion of construction takes over 10 years, and the total cost of the costs often exceeds hundreds of millions of dollars.

But even this huge amount is far from the limit. Astronomers' appetite is growing by leaps and bounds! The Hubble Space Observatory, launched in 1992, cost US taxpayers $ 3 billion. We have to admit that it exceeded all expectations in many ways!

James Webb Space Telescope

Next in line is the launch of another monster. If the project does not die out due to a deficit of budgetary funding, then the 6-meter space telescope James Webb promises to make a solid contribution to the series of the brightest discoveries and achievements.

In addition to money, its location plays an important role in the operation of the observatory. The ideal option is a launch into space, where there is no atmospheric distortion. But, since it is too expensive, accommodation in high-mountainous places is considered an acceptable solution. The higher the telescope is placed, the smaller the thickness of the interfering atmosphere. It always contains air inhomogeneities and turbulences.

When taking fine spectral analyzes, it is simply impossible to obtain reliable results while on the bottom of the air ocean. Therefore, all large observatories are built only high in the mountains. For example, the 8-meter telescope of the Japanese National Subaru Observatory is located on the top of a mountain, at an altitude of 4200 meters above sea level. Thanks to excellent atmospheric conditions, it was possible to achieve excellent quality of the resulting images.

In a modern city, getting good pictures is completely impossible. This is due to the presence of dust in the ambient air and a high level of illumination of the night sky. It should be said that the lights of a big city are able to cause a light background at a distance of over 50 km. Proceeding from this, single islands or sparsely populated high-mountain areas are chosen to accommodate large telescopes.

If you have ever visited the optical observatory, or just looked at its photographs, you might have noticed that it is always painted in bright white. This was done for a reason. In the daytime, the sun's rays noticeably heat any objects and structures. As a result, the dome of the observatory heats up so much that hot air begins to actively flow from its surface.

This effect is easy to notice yourself, observing distant objects on a hot day. On a hot day, hot air rushes upward, and you can see how the image seems to sway. This leads to the fact that it becomes impossible to carry out astronomical observations. To minimize the harmful effect, a reflective coating is applied to the observatory building, plus powerful cooling and ventilation systems are installed.

In most cases, the astronomical dome is spherical, rotating in all directions of the horizon. This is done so that you can direct the telescope lens to any point in the starry sky, just by turning the tower in the desired direction. From the top to the bottom, the dome is cut with a longitudinal cut and equipped with sliding doors. Thus, you can aim the telescope at any point in the sky - from the horizon to the vertical zenith line.

Observatory in Karachay-Cherkessia

In our country, the largest telescope is installed in a special astrophysical observatory in the Republic of Karachay-Cherkessia in the North Caucasus. Due to the fact that it is mounted at an altitude of just over 2000 meters above sea level, high quality of the resulting images is achieved. The main reflector mirror is 6 meters in diameter, bringing the ultimate magnitude for this instrument to an impressive + 25m! Until 1993, it remained the largest in the world, until the Keck Observatory was built. Today, the telescope is undergoing a deep modernization - the main mirror has been dismantled and sent to the manufacturer's plant for re-polishing. In addition, new electronic equipment for the tracking and guidance system will be installed.

An observatory is a scientific institution in which employees - scientists of various specialties - observe natural phenomena, analyze observations, and continue to study what happens in nature on their basis.


Astronomical observatories are especially widespread: we usually imagine them when we hear this word. They study 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 registration 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 being built in those areas that provide scientists with a maximum of material for research.


Meteorological - all over the world; astronomical - in the mountains (there the air 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 observatory. Astronomers in ancient times were priests, they kept a calendar, studied the movement of the Sun in the sky, were engaged in predictions of events, the fate of people, depending on the alignment of celestial bodies. They were astrologers - people who were feared even by the most ferocious rulers.

Ancient observatories were usually located in the upper rooms of the towers. A straight bar equipped with a sliding sight served as the tools.

The great astronomer of antiquity was Ptolemy, who collected in the Library of Alexandria a huge number of astronomical evidence, records, formed a catalog of positions and brightness for 1022 stars; invented the mathematical theory of planetary displacement and compiled tables of motion - scientists have 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 - monitored the movement of the Sun, describing it with unprecedented accuracy. The observatory with a radius of 40 m looked like a sextant-trench with a south orientation and marble trim.

The greatest astronomer of the European Middle Ages, who almost literally turned the world upside down, 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 the Sky Castle, owned by Tycho Brahe, the Danish court astronomer. The observatory was equipped with the best, most accurate instrument at that time, had its own workshop for the manufacture of instruments, a chemical laboratory, storage of books and documents, and even a printing press for their own needs and a paper mill for paper production - a royal luxury at that time!

In 1609, the first telescope appeared - the main instrument of any astronomical observatory. Galileo became its creator. It was a reflector telescope: the rays in it were refracted, passing through a series of glass lenses.

He improved the Kepler telescope: in his device the image was inverted, but of higher quality. This feature eventually became standard for telescopic instruments.

In the 17th century, with the development of navigation, state observatories began to appear - the Royal Parisian, the Royal Greenwich, observatories in Poland, Denmark, and 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, radio.

In 1839, the Pulkovo Observatory (St. Petersburg) was opened, which became one of the most famous in the world. Today in Russia there are more than 60 observatories. One of the largest on an international scale is the Pushchino Radio Astronomy Observatory, created in 1956.

The Zvenigorod Observatory (12 km from Zvenigorod) has the world's only WAU camera 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 "desert of telescopes" Atacama.


Yerkes Observatory in the United States - "the birthplace of astrophysics."

ORM Observatory(Canary Islands) - has an optical telescope with the largest aperture (the ability to collect light).

Arecibo- 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 Chinantor.

- You currently live and work in Chile. Which organization do you work for?

- I work at the Cerro Tololo Inter-American Observatory. This is a division of another organization that is not in Chile, but in the United States, the National Optical Astronomy Observatory (NOAO). This observatory was established in the late 1950s and serves the interests of the United States public observatory.

In all countries there is one science, but in America there are two: private and public.

Public astronomy, including us NOAO, is funded by taxpayers. The private sector operates on its own budgets and donations, and is generally more extensive and wealthy. Therefore, the entire history of our observatory is to some extent the history of the struggle between the personal and the public. Although, of course, we are one community. Our observatory was founded around the same time as the European Southern Observatory (ESO) in Chile. Behind this was the same man, Jürgen Stock, who researched places in Chile for better astroclimate. At one time we were the owners of the largest telescope in the Southern Hemisphere, when we installed the 4-meter Blanco telescope. This was in 1974, and until the end of the 1990s, our observatory occupied one of the leading positions in the world. By the way, in the mid-70s, a 6-meter telescope was also commissioned in the North Caucasus.

You can look back and see which telescope was more productive in terms of the number of discoveries. The answer, I hope you can guess for yourself.

Here is such an observatory. We have a four meter telescope in the Northern Hemisphere, Arizona. And there is this "four-meter" in the south, in Chile.

- That is, you get an overview of the whole sky? Is this some kind of prototype of the GEMINI project - two 8-meter telescopes, one of which is in the Northern Hemisphere in Hawaii and the other in the Southern Hemisphere, in Chile?

- Yes exactly. The actual idea for GEMINI originated in the late 1980s at NOAO, when a group of talented astronomers decided to make the largest telescope with a mirror 8 meters in diameter. This project was stopped, but then from its ashes, like Phoenix, GEMINI arose. Our observatory played a very important role in the development of GEMINI. We have provided qualified personnel. Many of the GEMINI employees in Chile are our people who once worked for us. We supported GEMINI, hoped they would be a sequel to NOAO. Although this is an international project, but its American part exists on taxpayers' money and, just like us, gives access to any researchers.

By the way, we have an open skies policy, and from Russia they can apply to us. There were such cases.

- And who from Russia came to you?

- Igor Antokhin worked here, Leonid Berdnikov came more than once. In general, people come to us from all over the world. Koreans often come, the French ... We have an open skies policy, that is, if a scientific project is interesting, we give time. We don’t give money, that is, we don’t pay for travel and stay. But people come for their money and watch, get data.

- Where is the best astroclimate in Chile? At Paranal, at Cerro Tololo, at the American observatory Las Campanas?

- The question is subtle. “Every sandpiper praises his swamp,” is a very accurate proverb in this case. Optical astronomy in Chile began with Cerro Tololo, ESO's La Silla Observatory and American Las Campanas. Then ESO made the bold decision to build an observatory on Paranal because of the good astroclimate. The decision was very bold, as it increased the cost of the project. The entire infrastructure had to be rebuilt there. But Paranal is a clear-weather pole across Latin America, with excellent image quality. Of course, there are places where there is more clear weather, for example, the Sahara Desert, but the astroclimate there is bad. The astroclimate in Paranal was excellent, but deteriorated in 1998 when the VLT entered service. Now it became clear that then it was not the astroclimate that worsened, but the readings of the instruments worsened, because they were distorted due to the design of the telescope. The telescope still produces excellent images.

Paranal's record is 0.2 arcsec image quality in the visible range.

This will not work anywhere, in any observatory in the world, only if as an exception. In principle, the astroclimate in Paranal is good. Las Campanas is also good, it is no coincidence that a 20-meter GMT telescope will be built there. But on the neighboring mountain, La Silla, the climate is not very good. And this is surprising, because these two mountains are close, literally in the same place, within the line of sight - and yet such a difference! The astroclimate in Cerro Tololo is somewhat worse, but it, by the way, is improving, because over the past 10 years, global processes have taken place in the Earth's atmosphere.

Astronomers have settled in Chile thanks to a stable anticyclone over the Atacama Desert, which provides downdrafts and, as a result, an excellent astroclimate. In the summer period, the anticyclone shifts to the south, and from the north it presses the tropical zone with clouds and precipitation. This phenomenon is called "Bolivian winter" and it partially affects Paranal as well. In the last decade, the anticyclone has been gradually migrating to the south. In our central zone, it is getting drier (astronomers rejoice, agriculture is crying), and in the north it rains in the summer. In February this year, a severe “Bolivian winter” caused flooding in northern Chile.

Well, in general, one cannot say which is better and which is worse, since it can be better in one parameter, and worse in another. Here the Americans were recently looking for a place for a 30-meter telescope. They surveyed 4-5 sites in Chile and several sites in other parts of the world. As a result, we chose Mauna Kea, although the quality of the images there is not better than ours.

But other parameters of the atmosphere turned out to be better for adaptive optics. Therefore, I can perfectly understand their choice.

- Can you compare the astroclimate in Chile with the astroclimate in the Special Astrophysical Observatory (SAO) in the North Caucasus and, say, in Uzbekistan?

- There is nothing to compare with CAO. SAO loses both in the amount of clear weather and in the quality of images. It's not even serious to talk about it.

SAO as an astronomical place should not be considered. The same can be said about Shatjatmas near Kislovodsk, where the GAISh MSU is building an educational observatory with a telescope with a diameter of 2.5 meters.

There the place was researched very well, very thoroughly, using the same methodology as in the whole world. The astroclimate there is quite decent, but it is not comparable to the best places in the world. This may be the best place in Russia, but not in the world. As for Uzbekistan, there are places with good image quality, for example, Mount Maidanak. Numerous studies were carried out there, including with ESO equipment. But in terms of clear weather and transparency of the atmosphere, Uzbekistan loses. Maidanak is a good place, maybe a hundred times (if all factors are multiplied and conditionally expressed in the price of a telescope) better than the North Caucasus. But if you compare it with Chile, the Canary Islands or Mauna Kea, then Maidanak will lose.

- Why did you decide to leave Russia?

- I didn’t leave Russia.

- But you live in Chile ...

- Yes, I live in Chile and work here. But I am still a Russian citizen, and I work here simply because it’s more interesting at the moment. I have only one motive to be here and work. Because I am here in the thick of things. I have the opportunity to build new equipment and use it. In Russia, I did not have such an opportunity. All my life I have been creating devices and I know very well how it is done in Russia and how it is done here. Here I can express myself more and more deeply, bring more benefit to science.

- The last question: do you think Russia needs to join ESO?

- It is difficult for me to formulate my opinion, I have been working not in Russian astronomy for ten years, so it would be tactless on my part to advise something. Of course, I am aware of these conversations, I communicate with colleagues. There are people who are strongly in favor and who are strongly against. In Brazil, for example, regarding the issue of joining ESO, there is also a party for and a party against.

The question is certainly controversial. I know the arguments of both those who are shouting for, and the position of those who are against.

But I would rather be with those who are for - this is my personal opinion. And many of my friends, whose opinion I respect, are also in favor.