Observatory. What is an observatory and what is it for? How celestial bodies are studied at the observatory

OBSERVATORY
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 the 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 are trying to be built high in the mountains. Radio observatories are often located in deep valleys, which are 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;
NEUTRINO ASTRONOMY;
RADIOLOCATION 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;
THE 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' observations and his own, Ptolemy compiled a catalog of the positions and brightness of 1,022 stars. Following Aristotle, he placed the Earth in the center of the world and believed that all the luminaries revolve around it. Together with his colleagues, Ptolemy conducted systematic observations of moving stars (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 over 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 to the target and moved the sight along it, achieving an exact match of the hole with the size of the star. Ptolemy and his colleagues improved many of the astronomical instruments. Carrying out careful observations with them and using trigonometry converting the instrumental readings into positional angles, they brought the measurement accuracy to about 10 "
(see also the PTOLEEMY of 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 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 established 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 conducted observations of the Sun with unprecedented accuracy. He used several smaller instruments to observe stars, the moon, and planets.
Revival. When in 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 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 theoreticians. New principles of work were approved along with new technology: a telescope came 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. Soon, telescopes 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 are refracted in it (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 for viewing 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. At first, 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 GEWELY Jan). 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 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 objectives of which were placed at the top of the mast and turned with a long stick or ropes, and the eyepiece was simply held in his hands (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, 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 assumed 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. Largely in connection with the needs of European observatories, the production of small high-precision machine tools has developed
(see also MEASURING INSTRUMENTS).
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, academicians set about revising astronomical constants and tables from scratch, taking Kepler's work as a 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, starting 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 activities 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 ephemeris - tables of the pre-calculated positions of the Sun, Moon and planets, necessary for cartography, navigation and fundamental astronomical research.
Introduction of standard time. The 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 state observatories of that era was to determine the coordinates of ships. Geographic latitude can be easily found from 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 \u200b\u200breflector, 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, timekeeping, 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. At first, the observers themselves made reflectors 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 a better image 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 use very strong magnification. Using one of his telescopes, Herschel discovered the planet Uranus, as well as thousands of binary stars and nebulae. In those years, many telescopes were built, 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 1.8 m reflector 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 went into philanthropy. Thus, J. Lick (1796-1876), who made a 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 firm "Alvan Clark and Sons" and installed in 1888. And in 1896 there, at the Lick Observatory, the 36-inch Crossley reflector, then the largest in the United States, began to work. ... Astronomer J. Hale (1868-1938) convinced 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 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, the 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 slowly cooling it to obtain high quality glass. It took more than six years to grind and polish the mirror to give it the necessary 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 it would never be surpassed.

But the advent of computers further expanded telescope construction. In 1976, the 6-meter BTA telescope (Large azimuth telescope) began to operate 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 \u200b\u200ba composite mirror, the Smithsonian Astrophysical Observatory in 1979 built a telescope 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 made up of 36 hexagonal segments, 183 cm across, controlled by a computer to produce a single image. Although the image quality is still not high, 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 the high altitude and very dry clean air. At the bottom right, through the open slot 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 APPARATUS
The photo. In the middle of the 19th century. several enthusiasts have begun 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 recording 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 similar to the Milky Way. In addition, Hubble discovered that galaxies are rapidly scattering from each other. This completely changed the idea of \u200b\u200bastronomers 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 deal with spectroscopy and collected a huge collection of stellar spectra. Its employees have classified thousands of stellar spectra and created a base 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 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 Ionospheric 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.

Permanent employees of national observatories monitor the health of equipment, develop new instruments and conduct 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 poor institutions to use the most advanced equipment.
Observations of the southern sky. Much of the southern sky is not visible from most observatories in Europe and the United States, although the southern sky 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 complete 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 the astrophysical observatory began to grow. At the end of the 20th century, when the 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, the 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 communication 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 living in dormitories and working 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 that independently work according to the planned program. Observations with space telescopes have a certain specificity. In the beginning, many astronomers, accustomed to working with the instrument on their own, felt uncomfortable in space astronomy, separated from the telescope not only by space, but also by many engineers and complex instructions. However, in the 1980s, at many ground-based observatories, the control of the telescope was transferred 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 the object, looking through a small telescope-finder attached to it and pressing buttons on a small hand-held remote control, the astronomer now sits in front of the TV guide screen and manipulates the joystick. Often an astronomer simply sends a detailed program of observations to the observatory via the Internet and, when they are made, receives the results directly into his computer. Therefore, the style of work with ground-based and space telescopes is becoming more and more similar.
MODERN LAND OBSERVATORIES
Optical observatories. The site for the construction of the optical observatory is usually chosen far from cities with their bright night illumination and smog. Usually this is the top of a mountain, where there is a thinner layer of the atmosphere through which observations must 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 over 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 sky of the Northern Hemisphere is better studied. In recent decades, large observatories have begun to be built in the southern hemisphere and near the equator, from where both northern and southern skies can be observed. The ancient volcano Mauna Kea on the island. Over 4 km high, 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 with a flat sliding roof. The towers of large telescopes are usually made round with a hemispherical rotating dome, in which a narrow slit opens for observation. Such a dome protects the telescope from wind well during operation. This is important because the wind shakes the telescope and causes the image to shake. Vibration from the ground and tower building also negatively affects image quality. Therefore, the telescope is mounted on a separate foundation that is not connected to the tower foundation. Inside the tower or near it, a ventilation system for the dome space and an installation for vacuum deposition on the telescope mirror of a reflecting aluminum layer that dims over time is mounted.
Crowbar. To aim at a star, the telescope must rotate around one or two axes. The first type includes the meridian circle and the transit instrument - small telescopes that rotate around the horizontal axis in the plane of the celestial meridian. Moving from east to west, each star crosses this plane twice a day. With the help of the transit instrument, the moments of the passage of stars through the meridian are determined and thus the speed of rotation of the Earth is specified; this is necessary for accurate time service. The meridian circle allows you to measure not only the moments, but also the place where the star crosses the meridian; this is necessary to create accurate maps of the starry sky. Direct visual observation is practically not used in modern telescopes. They are mainly used to photograph celestial objects or to register their light with electronic detectors; in this case, the exposure sometimes reaches several hours. All this time, the telescope must be accurately aimed at the object. Therefore, with the help of a clock mechanism, it rotates at a constant speed around the clockwise 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 hourly axis, is called the declination axis; it serves to point the telescope in a north-south direction. This design is called the equatorial mount and is used for almost all telescopes, with the exception of the largest ones, for which the alt-azimuth mount turned out to be more compact and cheaper. On it, the telescope follows the luminary, rotating simultaneously with variable speed around two axes - vertical and horizontal. This greatly complicates the operation of the clockwork, requiring computer control.

Refractor telescope has a lens lens. Since rays of different colors are refracted in glass in different ways, a lens objective is designed to give a clear image in focus in rays of a single color. Older refractors were created for visual observation and therefore gave a clear image in yellow rays. With the advent of photography, they began to build photographic telescopes - astrographs, which give a clear image in blue rays, to which a photographic emulsion is sensitive. Later, emulsions appeared that were sensitive to yellow, red and even infrared light. They can be used for photographing with visual refractors. Image size depends on the focal length of the lens. The focal length of the 102-cm Yerkes refractor is 19 m, so the diameter of the lunar disk at its focus is about 17 cm. The size of the photographic plates of this telescope is 20ґ25 cm; the full moon fits easily on them. Astronomers use glass photographic plates because of their high rigidity: even after 100 years of storage, they do not deform and make it possible to measure the relative position of stellar images with an accuracy of 3 microns, which for large refractors like the Yerkes one corresponds to an arc of 0.03 "in the sky.
Telescope reflector has a concave mirror as a lens. Its advantage over a refractor is that rays of any color are reflected from the mirror equally, providing a clear image. In addition, a mirrored lens can be made much larger than a lenticular lens, since the glass blank for the mirror may not be transparent inside; it can be protected from deformation under its own weight by placing it in a special frame that supports the mirror from below. The larger the diameter of the objective, the more light the telescope collects and the fainter and more distant objects it is able to "see". For many years, the largest in the world were the 6th reflector of the BTA (Russia) and the 5th reflector of the Palomar Observatory (USA). But now at the Mauna Kea observatory on Hawaii, two telescopes with 10-meter composite mirrors are operating and several telescopes with monolithic mirrors 8-9 m in diameter are under construction. Table 1.
THE WORLD'S LARGEST TELESCOPES
___
__Diameter ______ Observatory ______ Location and year of object (m) ________________ construction / dismantling

REFLECTORS

10.0 Mauna Kea Hawaii (USA) 1996 10.0 Mauna Kea Hawaii (USA) 1993 9.2 McDonald Texas (USA) 1997 8.3 National Japan Hawaii (USA) 1999 8.2 European Southern Sierra Mountain -Paranal (Chile) 1998 8.2 European South Mountain Sierra Paranal (Chile) 1999 8.2 European South Mountain Sierra Paranal (Chile) 2000 8.1 Gemini-North Hawaii (USA) 1999 6.5 University of Arizona Mount Hopkins (Arizona) 1999 6.0 Special Astrophysical Academy of Sciences of Russia st. Zelenchukskaya (Russia) 1976 5.0 Palomar Mountain Palomar (California) 1949 1.8 * 6 \u003d 4.5 University of Arizona Mount Hopkins (Arizona) 1979/1998 4.2 Roca de los Muchachos Canary Islands (Spain) 1986 4.0 Sierra Tololo Inter-American (Chile) 1975 3.9 Anglo-Australian Siding Spring (Australia) 1975 3.8 Kitt Peak National Tucson (Arizona) 1974 3.8 Mauna Kea (IC) Hawaii ( USA) 1979 3.6 European South La Silla (Chile) 1976 3.6 Mauna Kea Hawaii (USA) 1979 3.5 Roca de los Muchachos Canary Islands (Spain) 1989 3.5 Interuniversity Sacramento Peak (pcs . New Mexico) 1991 3.5 German-Spanish Calar Alto (Spain) 1983

REFRACTORS

1.02 Yerkes Williams Bay (Wisconsin) 1897 0.91 Mount Lick Hamilton (California) 1888 0.83 Paris Meudon (France) 1893 0.81 Potsdam Potsdam (Germany) 1899 0.76 French South Nice ( France) 1880 0.76 Allegheny Pittsburgh (Pennsylvania) 1917 0.76 Pulkovo St. Petersburg 1885/1941

CHAMBER SCHMIDT *

1.3-2.0 K. Schwarzschild Tautenburg (Germany) 1960 1.2-1.8 Palomar Mountain Palomar (California) 1948 1.2-1.8 Anglo-Australian Siding Spring (Australia) 1973 1, 1-1.5 Astronomical Tokyo (Japan) 1975 1.0-1.6 European Southern Chile 1972

SOLAR

1.60 Kitt Peak National Tucson (Arizona) 1962 1.50 Sacramento Peak (B) * Sunspot (New Mexico) 1969 1.00 Astrophysical Crimea (Ukraine) 1975 0.90 Kitt Peak (2 add.) * Tucson (Arizona) 1962 0.70 Kitt Peak (V) * Tucson (Arizona) 1975 0.70 Institute of Physics of the Sun, Germany Fr. Tenerife (Spain) 1988 0.66 Mitaka Tokyo (Japan) 1920 0.64 Cambridge Cambridge (England) 1820

Note: For Schmidt cameras, the diameter of the correction plate and the mirror is indicated; for solar telescopes: (V) - vacuum; 2 add. - two additional telescopes in a common housing with a 1.6-m telescope.
Mirror-lens cameras. The disadvantage of reflectors is that they only give a clear image near the center of the field of view. This does not interfere if one is studying one object. But patrol work, for example, the search for new asteroids or comets, requires photographing large areas of the sky at once. An ordinary reflector is not suitable for this. In 1932 the German optician B. Schmidt created a combined telescope, in which the defects of the main mirror are corrected with the help of a thin lens of complex shape located in front of it - a correction plate. The Schmidt camera of the Palomar Observatory receives on a 35ґ35 cm photographic plate an image of the 6ґ6 ° sky region. Another design of a wide-angle camera was created by D.D. Maksutov in 1941 in Russia. It is simpler than a Schmidt camera, since the role of a correction plate in it is played by a simple thick lens - a meniscus.
Operation of optical observatories. Now more than 100 large observatories function in more than 30 countries of the world. Usually, each of them, independently or in cooperation with others, conducts several multi-year observation programs. Astrometric measurements. Large national observatories - the US Marine Observatory, the Royal Greenwich Observatory in Great Britain (closed in 1998), Pulkovskaya in Russia, etc. - regularly measure the positions of stars and planets in the sky. This is a very delicate job; it is in it that the highest "astronomical" accuracy of measurements is achieved, on the basis of which catalogs of the position and movement of luminaries are created, which are necessary for ground and space navigation, to determine the spatial position of stars, to clarify the laws of planetary motion. For example, by measuring the coordinates of stars at intervals of six months, one can notice that some of them experience oscillations associated with the movement of the Earth in its orbit (the parallax effect). The magnitude of this displacement determines the distance to the stars: the smaller the displacement, the greater the distance. From Earth, astronomers can measure a displacement of 0.01 "(the thickness of a match 40 km away!), Which corresponds to a distance of 100 parsecs.
Meteor patrol. Multiple wide-angle cameras spaced apart over great distances continuously photograph the night sky to determine the trajectories of meteors and the possible impact of the meteorites. For the first time, these observations from two stations began at the Harvard Observatory (USA) in 1936 and under the direction of F. Whipple were carried out regularly until 1951. In 1951-1977 the same work was carried out at the Ondrejovskoy Observatory (Czech Republic). Since 1938 in the USSR, photographic observations of meteors have been carried out in Dushanbe and Odessa. Observations of meteors make it possible to study not only the composition of cosmic dust grains, but also the structure of the earth's atmosphere at altitudes of 50-100 km, which are difficult to access for direct sounding. The meteor patrol received the greatest development in the form of three "fireball nets" - in the USA, Canada and Europe. For example, the Smithsonian Observatory Prairie Network (USA) used 2.5 cm automatic cameras at 16 stations located 260 km around Lincoln, Nebraska, to photograph bright meteors - fireballs. Since 1963, the Czech fireball network developed, which later turned into a European network of 43 stations in the Czech Republic, Slovakia, Germany, Belgium, the Netherlands, Austria and Switzerland. Today it is the only active fireball network. Its stations are equipped with fisheye cameras, which make it possible to photograph the entire hemisphere of the sky at once. With the help of fireball nets, it was possible several times to find meteorites that fell to the ground and restore their orbit before colliding with the Earth.
Observations of the Sun. Many observatories regularly photograph the Sun. The number of dark spots on its surface serves as an indicator of activity, which periodically increases on average every 11 years, leading to disruption of radio communications, intensification of auroras and other changes in the Earth's atmosphere. The most important instrument for studying the Sun is the spectrograph. By passing sunlight through a narrow slit in the focus of a telescope and then decomposing it into a spectrum using a prism or diffraction grating, you can find out the chemical composition of the solar atmosphere, the speed of gas movement in it, its temperature and magnetic field. With the help of a spectroheliograph, you can take photographs of the Sun in the emission line of one element, for example, hydrogen or calcium. They clearly show prominences - huge clouds of gas flying up over the surface of the Sun. Of great interest is the hot rarefied region of the solar atmosphere - the corona, which is usually visible only during total solar eclipses. However, at some high-altitude observatories, special telescopes have been created - extra-eclipse coronagraphs, in which a small shutter ("artificial moon") closes the bright disk of the Sun, making it possible to observe its corona at any time. Such observations are carried out on Capri Island (Italy), at the Sacramento Peak Observatory (New Mexico, USA), Pique du Midi (French Pyrenees) and others.

Observations of the moon and planets. The surface of planets, satellites, asteroids and comets is studied using spectrographs and polarimeters, determining the chemical composition of the atmosphere and the features of the solid surface. The Lovell Observatory (Arizona), Medonskaya and Pique du Midi (France), and Crimean Observatory (Ukraine) are very active in these observations. Although in recent years many remarkable results have been obtained using spacecraft, ground-based observations have not lost their relevance and bring new discoveries every year.
Observing the stars. By measuring the intensity of lines in the spectrum of a star, astronomers determine the abundance of chemical elements and the temperature of the gas in its atmosphere. The position of the lines, based on the Doppler effect, determines the speed of the star as a whole, and the shape of the line profile determines the speed of gas flows in the atmosphere of the star and the speed of its rotation around the axis. Lines of rarefied interstellar matter located between the star and the terrestrial observer are often visible in the spectra of stars. By systematically observing the spectrum of one star, one can study the oscillations of its surface, establish the presence of satellites and flows of matter, sometimes flowing from one star to another. With a spectrograph placed at the focus of the telescope, a detailed spectrum of only one star can be obtained in tens of minutes of exposure. For the mass study of the spectra of stars, a large prism is placed in front of the lens of a wide-angle (Schmidt or Maksutov) camera. In this case, a section of the sky is obtained on a photographic plate, where each image of a star is represented by its spectrum, the quality of which is low, but sufficient for the mass study of stars. Such observations have been carried out for many years at the University of Michigan Observatory (USA) and at the Abastumani Observatory (Georgia). Fiber optic spectrographs have recently been created: optical fibers are placed in the focus of the telescope; each of them is placed with one end on the image of the star, and with the other on the slit of the spectrograph. So in one exposure, you can get detailed spectra of hundreds of stars. By passing light from a star through various filters and measuring its brightness, it is possible to determine the color of the star, which indicates the temperature of its surface (the bluer, the hotter) and the amount of interstellar dust lying between the star and the observer (the more dust, the redder the star). Many stars periodically or chaotically change their brightness - they are called variables. Variations in brightness associated with oscillations of the surface of a star or with mutual eclipses of the components of binary systems tell a lot about the internal structure of stars. When exploring variable stars, it is important to have long and dense observation series. Therefore, astronomers often involve amateurs in this work: even eye estimates of the brightness of stars through binoculars or a small telescope are of scientific value. Astronomy lovers often form clubs for joint observations. In addition to studying variable stars, they often discover comets and outbursts of new stars, which also make a significant contribution to astronomy. Faint stars are studied only with large telescopes with photometers. For example, a telescope with a diameter of 1 meter collects light 25,000 times more than the pupil of the human eye. The use of a photographic plate with a long exposure increases the sensitivity of the system thousands of times. Modern photometers with electronic light detectors, such as a photomultiplier tube, an image converter or a semiconductor CCD matrix, are ten times more sensitive than photographic plates and allow direct recording of measurement results into computer memory.
Observation of faint objects. Observations of distant stars and galaxies are carried out using the largest telescopes with a diameter of 4 to 10 m.The leading role in this belongs to the observatories Mauna Kea (Hawaii), Palomarskaya (California), La Silla and Sierra Tololo (Chile), Special Astrophysical ). Large Schmidt cameras at the Tonantzintla (Mexico), Mount Stromlo (Australia), Bloemfontein (South Africa), Byurakan (Armenia) observatories are used for the mass study of faint objects. These observations make it possible to penetrate the deepest into the Universe and study its structure and origin.
Joint observation programs. Many observational programs are carried out jointly by several observatories, the interaction of which is supported by the International Astronomical Union (IAU). It unites about 8 thousand astronomers from all over the world, has 50 commissions in various fields of science, once every three years, gathers large Assemblies and annually organizes several large symposia and colloquia. Each IAS commission coordinates observations of objects of a certain class: planets, comets, variable stars, etc. The IAU coordinates the work of many observatories in the compilation of star maps, atlases and catalogs. At the Smithsonian Astrophysical Observatory (USA), the Central Bureau of Astronomical Telegrams operates, which quickly notifies all astronomers about unexpected events - outbursts of new stars and supernovae, the discovery of new comets, etc.
RADIO OBSERVATORIES
The development of radio communication technology in the 1930-1940s made it possible to begin radio observation of space bodies. This new "window" into the universe has brought many amazing discoveries. Of the entire spectrum of electromagnetic radiation, only optical and radio waves pass through the atmosphere to the Earth's surface. Moreover, the "radio window" is much wider than the optical one: it extends from millimeter waves to tens of meters. In addition to the objects known in optical astronomy - the Sun, planets and hot nebulae - previously unknown objects turned out to be sources of radio waves: cold clouds of interstellar gas, galactic nuclei and exploding stars.
Types of radio telescopes. Radio emission from space objects is very weak. To notice it against the background of natural and artificial interference, narrow directional antennas are needed that receive a signal from only one point in the sky. These antennas are of two types. For short-wave radiation, they are made of metal in the form of a concave parabolic mirror (like in an optical telescope), which concentrates the incident radiation in focus. Such reflectors up to 100 m in diameter - full-turn - are capable of looking into any part of the sky (like an optical telescope). Larger antennas are made in the form of a parabolic cylinder that can rotate only in the meridian plane (like an optical meridian circle). Rotation around the second axis provides rotation of the Earth. The largest paraboloids are made stationary using natural hollows in the ground. They can only observe a limited area of \u200b\u200bthe sky. Table 2.
LARGEST RADIO TELESCOPES
________________________________________________
Largest __ Observatory _____ Location and year _ Size ____________________ of construction / dismantling
antennas (m)
________________________________________________
1000 1 Lebedev Physical Institute, RAS Serpukhov (Russia) 1963 600 1 Special Astrophysical Academy of Sciences of Russia North Caucasus (Russia) 1975 305 2 Ionospheric Arecibo Arecibo (Puerto Rico) 1963 305 1 Meudon Meudon (France) 1964 183 University of Illinois Danville (Illinois) 1962 122 University of California Hat Creek (CA) 1960 110 1 University of Ohio Delaware (Ohio) 1962 107 Stanford Radio Laboratory Stanford (California) 1959 100 Max Planck Bonn (Germany) 1971 76 Jodrell-Bank Macclesfield (England) 1957 ________________________________________________
Notes:
1 unfilled aperture antenna;
2 fixed antenna. ________________________________________________
Antennas for long-wave radiation are assembled from a large number of simple metal dipoles, placed over an area of \u200b\u200bseveral square kilometers and interconnected so that the signals they receive amplify each other only if they come from a certain direction. The larger the antenna, the narrower the area in the sky it examines, while giving a clearer picture of the object. An example of such a tool is the UTR-2 (Ukrainian T-shaped radio telescope) of the Kharkov Institute of Radiophysics and Electronics of the Academy of Sciences of Ukraine. The length of its two arms is 1860 and 900 m; it is the most advanced instrument in the world for studying decameter radiation in the 12-30 m range.The principle of combining several antennas into a system is also used for parabolic radio telescopes: by combining signals received from one object by several antennas, they receive, as it were, one signal from an equivalent in size. giant antenna. This significantly improves the quality of the received radio images. Such systems are called radio interferometers, since signals from different antennas add up and interfere with each other. The quality of images from radio interferometers is not worse than optical ones: the smallest details are about 1 "in size, and if you combine signals from antennas located on different continents, then the size of the smallest details in the image of an object can be reduced thousands of times. The signal collected by the antenna is detected and amplified. a special receiver - a radiometer, which is usually tuned to one fixed frequency or changes tuning in a narrow frequency band. To reduce intrinsic noise, radiometers are often cooled to very low temperatures. The amplified signal is recorded on a tape recorder or computer. The received signal strength is usually expressed in terms of "antenna temperature ", as if an absolutely black body of a given temperature was in place of the antenna, emitting the same power. By measuring the signal power at different frequencies, a radio spectrum is constructed, the shape of which makes it possible to judge the mechanism of radiation and the physical nature of the object. Radio astronomy observations can be carried out but whose and during the day, if no interference from industrial facilities interferes: sparking electric motors, broadcast radio stations, radars. For this reason, radio observatories are usually set up far from cities. Radio astronomers have no special requirements for the quality of the atmosphere, but when observing at wavelengths shorter than 3 cm, the atmosphere becomes a hindrance, so they prefer to place short-wave antennas high in the mountains. Some radio telescopes are used as radars, sending a powerful signal and receiving a pulse reflected from an object. This allows you to accurately determine the distance to planets and asteroids, measure their speed and even build a surface map. This is how the maps of the surface of Venus were obtained, which is not visible in optics through its dense atmosphere.
see also
RADIOASTRONOMY;
RADIOLOCATION ASTRONOMY.
Radio astronomical observations. Depending on the antenna parameters and the available equipment, each radio observatory specializes in a certain class of observation objects. The sun, due to its proximity to the earth, is a powerful source of radio waves. The radio emission coming from its atmosphere is constantly recorded - this makes it possible to predict solar activity. Active processes take place in the magnetospheres of Jupiter and Saturn, radio pulses from which are regularly observed at the observatories of Florida, Santiago and Yale University. The largest antennas in England, USA and Russia are used for planetary radar. A remarkable discovery was the radiation of interstellar hydrogen at a wavelength of 21 cm discovered at the Leiden Observatory (Netherlands). Then, dozens of other atoms and complex molecules, including organic ones, were found by radio lines in the interstellar medium. Molecules emit especially intensely at millimeter waves, for the reception of which special parabolic antennas with a high-precision surface are created. First at the Cambridge Radio Observatory (England), and then at others, since the early 1950s, systematic all-sky surveys have been carried out to identify radio sources. Some of them coincide with the known optical objects, but many have no analogues in other radiation ranges and, apparently, are very distant objects. In the early 1960s, after discovering faint stellar objects that coincided with radio sources, astronomers discovered quasars - very distant galaxies with incredibly active nuclei. From time to time, on some radio telescopes, attempts are made to search for signals from extraterrestrial civilizations. The first project of this kind was the US National Radio Astronomy Observatory's project in 1960 to search for signals from the planets of nearby stars. Like all subsequent searches, he returned a negative result.
EXTRA ATMOSPHERIC ASTRONOMY
Since the Earth's atmosphere does not transmit X-rays, infrared, ultraviolet and some types of radio radiation to the planet's surface, instruments for their study are installed on artificial Earth satellites, space stations or interplanetary vehicles. These devices require low weight and high reliability. Usually, specialized astronomical satellites are launched to observe in a certain range of the spectrum. Even optical observations are preferable to be carried out outside the atmosphere, which significantly distorts the images of objects. Unfortunately, space technology is very expensive, so extra-atmospheric observatories are created either by the richest countries, or by several countries in cooperation with each other. Initially, certain groups of scientists were involved in the development of instruments for astronomical satellites and the analysis of the data obtained. But as the productivity of space telescopes grew, a system of cooperation was formed, similar to that adopted at national observatories. For example, the Hubble Space Telescope (USA) is available to any astronomer in the world: applications for observations are accepted and evaluated, the most worthy of them are carried out and the results are transmitted to the scientist for analysis. These activities are organized by the Space Telescope Science Institute.
- (new lat. observatorium, from observare to observe). Building for physical and astronomical observations. Dictionary of foreign words included in the Russian language. Chudinov AN, 1910. OBSERVATORY building, serving for astronomical, ... ... Dictionary of foreign words of the Russian language

OBSERVATORY, an institution for the production of astronomical or geophysical (magnetometric, meteorological and seismic) observations; hence the division of observatories into astronomical, magnetometric, meteorological and seismic.

Astronomical observatory

According to their purpose, astronomical observatories can be divided into two main types: astrometric and astrophysical observatories. Astrometric observatories are engaged in determining the exact positions of stars and other luminaries for different purposes and, depending on this, using different tools and methods. Astrophysical observatories study various physical properties of celestial bodies, for example, temperature, brightness, density, as well as other properties that require physical methods of research, for example, the movement of stars along the line of sight, the diameters of stars determined by the interference method, etc. Many large observatories pursue mixed purposes, but there are observatories for a narrower purpose, for example, for observing the variability of geographical latitude, for searching for minor planets, observing variable stars, etc.

Location of the observatory must meet a number of requirements, which include: 1) complete absence of shaking caused by the proximity of railways, traffic or factories, 2) the greatest purity and transparency of the air - no dust, smoke, fog, 3) no illumination of the sky caused by the proximity of the city , factories, railway stations, etc., 4) calm air at night, 5) a fairly open horizon. Conditions 1, 2, 3, and partly 5 force the observatories to be moved out of town, often even to considerable heights above sea level, creating mountain observatories. Condition 4 depends on a number of reasons, partly of a general climatic (winds, humidity), partly of a local character. In any case, it forces you to avoid places with strong air currents, for example, arising from strong heating of the soil by the sun, sharp fluctuations in temperature and humidity. The most favorable are areas covered with a uniform vegetation cover, with a dry climate, at a sufficient height above sea level. Modern observatories usually consist of separate pavilions, located in the middle of a park or scattered over a meadow, in which instruments are installed (Fig. 1).

To the side are laboratories - rooms for measuring and computing work, for studying photographic plates and for performing various experiments (for example, for studying the radiation of an absolutely black body, as a standard for determining the temperature of stars), a mechanical workshop, a library and living quarters. One of the buildings has a basement for a clock. If the observatory is not connected to the electric main, then its own power plant is set up.

Instrumental equipment of observatories can be very diverse depending on the purpose. To determine the right ascensions and declinations of the luminaries, the meridian circle is used, giving both coordinates at the same time. At some observatories, following the example of the Pulkovo Observatory, two different instruments are used for this purpose: a passage instrument and a vertical circle, which allow the above coordinates to be determined separately. The most observations are divided into fundamental and relative. The first consists in the independent derivation of an independent system of right ascensions and declinations with the determination of the position of the vernal equinox and the equator. The second consists in linking the observed stars, usually located in a narrow zone in declination (hence the term: zone observations), to the reference stars, the position of which is known from fundamental observations. For relative observations, photography is now more and more used, and this area of \u200b\u200bthe sky is taken with special tubes with a camera (astrographs) with a sufficiently large focal length (usually 2-3.4 m). The relative determination of the position of objects close to each other, for example, double stars, minor planets and comets, in relation to nearby stars, planetary satellites relative to the planet itself, the determination of annual parallaxes - is performed using the equatorials both visually - using an eyepiece micrometer, and photographic, in which the eyepiece is replaced by a photographic plate. For this purpose, the largest instruments are used, with lenses from 0 to 1 m. The variability of latitude is studied mainly with the help of zenith telescopes.

The main observations of an astrophysical nature are photometric, including colorimetry, that is, the determination of the color of stars, and spectroscopic. The former are made using photometers installed as independent instruments or, more often, attached to a refractor or reflector. Spectrographs with a slit are used for spectral observations, which are attached to the largest reflectors (with a mirror from 0 to 2.5 m) or, in obsolete cases, to large refractors. The resulting photographs of the spectra are used for various purposes, such as: determination of radial velocities, spectroscopic parallaxes, and temperature. For a general classification of stellar spectra, more modest instruments can be used - the so-called. prism cameras, consisting of a high-aperture short-focus photographic camera with a prism in front of the lens, giving spectra of many stars on one plate, but with low dispersion. For spectral studies of the sun, as well as stars, at some observatories the so-called. tower telescopespresenting known advantages. They consist of a tower (up to 45 m high), at the top of which a cellostat is installed, which sends the rays of the sun vertically downward; a lens is placed slightly below the whole, through which the rays pass, gathering in focus at ground level, where they enter a vertical or horizontal spectrograph under constant temperature conditions.

The aforementioned tools are mounted on solid stone pillars with deep and large foundations, isolated from the rest of the building so that no shock is transmitted. Refractors and reflectors are placed in round towers (Fig. 2) covered with a hemispherical rotating dome with a drop-down hatch through which observation takes place.

For refractors, the floor in the tower is made lifting, so that the observer can comfortably reach the eyepiece end of the telescope at any inclinations of the latter to the horizon. In reflector towers, ladders and small lifting platforms are usually used instead of a lifting floor. Large reflector towers should be designed so that they provide good thermal insulation during the day against heating and adequate ventilation at night when the dome is open. Instruments intended for observation in one definite vertical — the meridian circle, the passage instrument, and partly the vertical circle — are installed in corrugated iron pavilions (Fig. 3) in the form of a lying half-cylinder. By opening wide hatches or rolling back walls, a wide gap is formed in the plane of the meridian or the first vertical, depending on the installation of the instrument, which allows observation.

The design of the pavilion should provide for good ventilation, since when observing, the air temperature inside the pavilion should be equal to the external temperature, which eliminates the incorrect refraction of the line of sight, called hall refraction (Saalrefraktion). With transit instruments and meridian circles, worlds are often arranged, which are solid marks set in the plane of the meridian at some distance from the instrument.

Observatories serving time, as well as making fundamental determinations of right ascension, require a large clock installation. The clock is placed in a basement, in a constant temperature environment. In a special room, distribution boards and chronographs are placed to compare watches. A receiving radio station is also installed here. If the observatory itself gives the time signals, then another installation is required for the automatic sending of signals; the transmission is made through one of the powerful transmitting radio stations.

In addition to permanently functioning observatories, temporary observatories and stations are sometimes set up, intended either for observing short-term phenomena, mainly solar eclipses (before also the transit of Venus across the disk of the sun), or for performing certain work, after which such an observatory is closed again. So, some European and especially North American observatories opened temporary - for several years - offices in the southern hemisphere for observing the southern sky in order to compile positional, photometric or spectroscopic catalogs of southern stars with the same methods and instruments that were used for the same purpose at the main observatory in the northern hemisphere. The total number of currently operating astronomical observatories reaches 300. Some data, namely: location, main instruments and basic work on the main modern observatories are given in the table.

Magnetic observatory

The Magnetic Observatory is a station that regularly monitors geomagnetic elements. It is a reference point for geomagnetic survey of the adjacent area. The material provided by the magnetic observatory is fundamental in the study of the magnetic life of the earth. The work of the magnetic observatory can be divided into the following cycles: 1) the study of temporal variations in the elements of terrestrial magnetism, 2) their regular measurements in an absolute measure, 3) the study and study of geomagnetic instruments used in magnetic surveys, 4) special research work in areas of geomagnetic phenomena.

To carry out these works, the magnetic observatory has a set of normal geomagnetic instruments for measuring the elements of terrestrial magnetism in an absolute measure: magnetic theodolite and an inclinator, usually of the induction type, as more advanced. These devices d. B. are compared with standard instruments available in each country (in the USSR they are stored in the Slutsk Magnetic Observatory), in turn compared with the international standard in Washington. To study temporal variations of the earth's magnetic field, the observatory has at its disposal one or two sets of variometers - variometers D, H and Z - that provide continuous recording of changes in the elements of earth's magnetism over time. The principle of operation of the above devices - see Terrestrial magnetism. The most common designs are described below.

A magnetic theodolite for absolute H measurements is shown in FIG. 4 and 5. Here A is a horizontal circle, readings along which are taken using microscopes B; I - tube for observations by the autocollimation method; C - a house for a magnet m, D - an arrester fixed at the base of a tube, inside which a thread runs to support a magnet m. At the top of this tube there is a head F, to which the thread is attached. Deflection (auxiliary) magnets are placed on lagers M 1 and M 2; the orientation of the magnet on them is determined by special circles with readings using microscopes a and b. Observations of declination are carried out using the same theodolite, or a special declinator is installed, the design of which is in general the same as that of the described device, but without devices for deviations. To determine the place of true north on the azimuth circle, a specially set measure is used, the true azimuth of which is determined using astronomical or geodetic measurements.

An earth inductor (inclinator) for determining inclination is shown in FIG. 6 and 7. The double coil S can rotate about an axis lying on bearings mounted in the ring R. The position of the axis of rotation of the coil is determined along the vertical circle V using microscopes M, M. H is a horizontal circle serving to set the axis of the coil in the plane of the magnetic meridian, K - a switch for converting an alternating current obtained by rotating the coil into a direct current. From the terminals of this commutator, the current is fed to a sensitive galvanometer with a satazed magnetic system.

Variometer H is shown in FIG. 8. Inside a small chamber, a magnet M is suspended on a quartz thread or on a bifilar. The upper attachment point of the thread is located at the top of the suspension tube and is connected with a head T that can rotate about a vertical axis.

A mirror S is inseparably attached to the magnet, onto which a beam of light falls from the illuminator of the recording apparatus. A fixed mirror B is fixed next to the mirror, the purpose of which is to draw a base line on the magnetogram. L is a lens that gives an image of the illuminator slit on the drum of the recording apparatus. A cylindrical lens is installed in front of the drum, reducing this image to a point. T. about. Recording on photographic paper wound on the drum is made by moving the light spot along the generatrix of the drum from the light beam reflected from the mirror S. The construction of the variometer B is the same in detail as the described device, except for the orientation of the magnet M in relation to the mirror S.

The variometer Z (Fig. 9) essentially consists of a magnetic system oscillating about a horizontal axis. The system is enclosed inside the chamber 1, which has an opening in its front part, closed by a lens 2. The oscillations of the magnetic system are recorded by the recorder thanks to a mirror that is attached to the system. A stationary mirror located next to a movable one serves to build a base line. The general arrangement of the variometers during observations is shown in Fig. ten.

Here R is a recording apparatus, U is its clockwork, which rotates a drum W with light-sensitive paper, l is a cylindrical lens, S is an illuminator, H, D, Z are variometers for the corresponding elements of terrestrial magnetism. In variometer Z, the letters L, M and t denote, respectively, a lens, a mirror connected to the magnetic system, and a mirror attached to a device for recording temperatures. Depending on those special tasks, in the solution of which the observatory takes part, its further equipment has a special character. Reliable operation of geomagnetic devices requires special conditions in the sense of the absence of disturbing magnetic fields, constant temperature, etc .; therefore magnetic observatories are carried far beyond the city with its electrical installations and are so arranged to guarantee the desired degree of temperature constancy. For this, pavilions where magnetic measurements are made are usually built with double walls and the heating system is located along a corridor formed by the outer and inner walls of the building. In order to exclude the mutual influence of variational devices on normal ones, both are usually installed in different pavilions, somewhat distant from each other. When constructing such buildings, d. B. special attention is paid to the fact that there are no iron masses, especially moving ones, inside and nearby. With regard to wiring, d. B. the conditions are met, guaranteeing the absence of magnetic fields of electric current (bifilar wiring). The proximity of structures that create mechanical shocks is unacceptable.

Since the magnetic observatory is the main point for studying magnetic life: the earth, it is quite natural to require b. or m. their even distribution over the entire surface of the globe. At the moment this requirement has been met only approximately. The table below, presenting a list of magnetic observatories, gives an idea of \u200b\u200bthe extent to which this requirement has been met. In the table, italics indicate the average annual change in the element of terrestrial magnetism, due to the secular course.

The richest material collected by magnetic observatories is the study of temporal variations in geomagnetic elements. This includes the diurnal, annual and secular variations, as well as those sudden changes in the earth's magnetic field, which are called magnetic storms. As a result of the study of diurnal variations, it became possible to isolate in them the influence of the position of the sun and moon in relation to the place of observation and to establish the role of these two cosmic bodies in diurnal changes in geomagnetic elements. The main cause of variation is the sun; the influence of the moon does not exceed 1/15 of the action of the first star. The amplitude of daily fluctuations on average has a value of the order of 50 γ (γ \u003d 0.00001 gauss, see Earth magnetism), that is, about 1/1000 of the total stress; it varies depending on the geographical latitude of the observation site and depends to a large extent on the season. As a rule, the amplitude of diurnal variations in summer is greater than in winter. The study of the distribution of magnetic storms in time led to the establishment of their connection with the activity of the sun. The number of storms and their intensity coincide in time with the number of sunspots. This circumstance allowed Stormer to create a theory explaining the occurrence of magnetic storms by the penetration into the upper layers of our atmosphere of electric charges ejected by the sun during the periods of its greatest activity, and the parallel formation of a ring of moving electrons at a considerable height, almost beyond the atmosphere, in the plane of the earth's equator.

Meteorological observatory

Meteorological observatory, the highest scientific institution for the study of issues related to the physical life of the earth in the broadest sense. At present these observatories are engaged not only in purely meteorological and climatological questions and in the weather service, but also include in their range of tasks questions of terrestrial magnetism, atmospheric electricity and atmospheric optics; some observatories even carry out seismic observations. Therefore, such observatories bear a broader name - geophysical observatories or institutes.

Observatories' own observations in the field of meteorology have in mind to provide strictly scientific material of observations made on meteorological elements, necessary for climatology, weather services and to satisfy a number of practical requests based on recordings of recorders with continuous registration of all changes in the course of meteorological elements. Direct observations at certain urgent hours are made over such elements as air pressure (see Barometer), its temperature and humidity (see Hygrometer), over the direction and speed of wind, sunshine, precipitation and evaporation, snow cover, soil temperature and other atmospheric phenomena under the program of privates of meteorology, stations of the 2nd category. In addition to these programmed observations, control observations are carried out at meteorological observatories, as well as studies of a methodological nature are carried out, expressed in the establishment and testing of new methods of observation over phenomena that have already been partially studied; never studied at all. Observations of observatories should be long-term in order to be able to draw a number of conclusions from them to obtain average "normal" values \u200b\u200bwith sufficient accuracy, to determine the magnitude of non-periodic fluctuations inherent in a given place of observation, and to determine patterns in the course of these phenomena over time.

In addition to making their own meteorological observations, one of the major tasks of observatories is to study the entire country as a whole or its individual areas in physical relations and Ch. arr. in terms of climate. The observational material coming from the network of meteorological stations to the observatory is subjected here to detailed study, control and thorough verification in order to select the most benign observations that can already go for further study. Initial conclusions from this tested material are published in the observatory publications. Such publications on the network of stations of the former. Russia and the USSR cover observations starting in 1849. In these editions Ch. arr. conclusions from observations, and only for a small number of observation stations are printed in full.

The rest of the processed and verified material is kept in the archives of the observatory. As a result of a deep and thorough study of these materials, from time to time, various monographs appear, either characterizing the processing technique or concerning the development of individual meteorological elements.

One of the specific features of the observatories' activities is a special weather forecast and notification service. At present, this service is separated from the Main Geophysical Observatory in the form of an independent institute - the Central Weather Bureau. To show the development and achievements of our weather service, below are data on the number of telegrams received by the Weather Bureau per day, starting from 1917.

At present, the Central Weather Bureau receives up to 700 internal telegrams alone in addition to reports. In addition, major work is being done here to improve weather forecasting methods. As for the degree of success of short-term predictions, it is determined at 80-85%. In addition to short-term forecasts, methods have now been developed and long-term predictions of the general nature of the weather for the coming season or for short periods, or detailed predictions on specific issues (opening and freezing of rivers, floods, thunderstorms, snowstorms, hail, etc.) are being given.

In order for the observations made at the stations of the meteorological network to be comparable with each other, it is necessary that the instruments used for these observations are compared with the "normal" standards adopted at international congresses. The task of checking the instruments is resolved by a special department of the observatory; at all stations of the network, only instruments tested at the observatory and provided with special certificates that give either corrections or permanent ones for the corresponding instruments under given observation conditions are used. In addition, for the same purposes of comparability of the results of direct meteorological observations at stations and observatories, these observations must be made in strictly defined terms and according to a certain program. In view of this, the observatory issues special instructions for making observations, revised from time to time on the basis of experiments, scientific progress and in accordance with the decisions of international congresses and conferences. The observatory calculates and publishes special tables for processing meteorological observations made at the stations.

In addition to meteorological, a number of observatories also conduct actinometric studies and systematic observations of the intensity of solar radiation, over diffuse radiation and over the earth's own radiation. In this respect, the observatory in Slutsk (former Pavlovsk) is well-known, where a large number of instruments have been designed both for direct measurements and for continuous automatic recording of changes in various radiation elements (actinographs), and these instruments were installed here to operate earlier than at observatories in other countries. In some cases, studies are underway to study the energy in individual parts of the spectrum, in addition to integral radiation. Questions related to the polarization of light are also the subject of a special study of observatories.

Scientific flights on balloons and free balloons, carried out repeatedly for direct observations of the state of meteorological elements in a free atmosphere, although they provided a number of very valuable data for understanding the life of the atmosphere and the laws governing it, nevertheless, these flights had only very limited application in everyday life due to the significant costs associated with them, as well as the difficulty of reaching great heights. The successes of aviation made persistent requirements for clarifying the state of meteorological elements and Ch. arr. wind directions and speeds at different heights in a free atmosphere, etc. put forward the importance of aerological research. Special institutes were organized, special methods were developed for lifting recorders of various designs, which are raised to a height on kites or with the help of special rubber balloons filled with hydrogen. Recordings of these recorders provide information on the state of pressure, temperature and humidity, as well as on the speed and direction of air at various altitudes in the atmosphere. In the case when information is required only about the wind in different layers, observations are made over small pilot balloons freely released from the observation point. In view of the enormous importance of such observations for the purposes of air transport, the observatory organizes a whole network of aerological points; the processing of the results of the observations, as well as the solution of a number of problems of theoretical and practical importance, concerning the movement of the atmosphere, are carried out at observatories. Systematic observations at high-altitude observatories also provide material for understanding the laws of atmospheric circulation. In addition, such high-altitude observatories are important in issues related to the feeding of rivers originating from glaciers and related issues of irrigation, which is important in semi-desert climates, for example, in Central Asia.

Turning to observations of the elements of atmospheric electricity carried out at observatories, it is necessary to point out that they have a direct connection with radioactivity and, in addition, have a certain significance in the development of agricultural science. cultures. The purpose of these observations is to measure the radioactivity and the degree of ionization of the air, as well as to determine the electrical state of precipitation falling on the ground. Any disturbances that occur in the earth's electric field cause disturbances in wireless and sometimes even wire communication. Observatories located at coastal points include in their program of work and research the study of sea hydrology, observations and forecasts of the state of the sea, which is of direct importance for the purposes of maritime transport.

In addition to obtaining observational data, processing it and possible conclusions, in many cases it seems necessary to subject the phenomena observed in nature to experimental and theoretical study. Hence the tasks of laboratory and mathematical research carried out by observatories. Under the conditions of laboratory experiments, it is sometimes possible to reproduce this or that atmospheric phenomenon, to comprehensively study the conditions of its occurrence and its causes. In this regard, one can point to the work carried out at the Main Geophysical Observatory, for example, to study the phenomenon of bottom ice and determine measures to combat this phenomenon. In the same way, the observatory laboratory studied the question of the rate of cooling of a heated body in an air stream, which is directly related to the solution of the problem of heat transfer in the atmosphere. Finally, mathematical analysis finds wide application in solving a number of problems related to processes and various phenomena occurring in atmospheric conditions, for example, circulation, turbulent motion, etc. In conclusion, we give a list of observatories located in the USSR. In the first place should be put the Main Geophysical Observatory (Leningrad), founded in 1849; next to her as her suburban branch is the observatory in Slutsk. These institutions perform tasks throughout the Union. In addition to them, a number of observatories with functions of republican, regional or regional significance: the Geophysical Institute in Moscow, the Middle Asian Meteorological Institute in Tashkent, the Geophysical Observatory in Tiflis, Kharkov, Kiev, Sverdlovsk, Irkutsk and Vladivostok, organized by the Geophysical Institutes in Saratov for Nizhne- Volga region and Novosibirsk for Western Siberia. There are a number of observatories on the seas - in Arkhangelsk and a newly organized observatory in Aleksandrovsk for the northern basin, in Kronstadt for the Baltic Sea, in Sevastopol and Feodosia for the Black and Azov Seas, in Baku for the Caspian Sea and in Vladivostok for the Pacific Ocean. A number of former universities also have observatories with major works in the field of meteorology and geophysics in general - Kazan, Odessa, Kiev, Tomsk. All these observatories not only conduct observations at one point, but also organize expeditionary research, either of an independent or complex nature, on various issues and departments of geophysics, which greatly contribute to the study of the productive forces of the USSR.

Seismic observatory

Seismic observatory serves for registration and study of earthquakes. The main instrument in the measuring practice of earthquakes is a seismograph, which automatically records every shock that occurs in a certain plane. Therefore, a series of three devices, two of which are horizontal pendulums that capture and record those components of motion or velocity that are performed in the direction of the meridian (NS) and parallel (EW), and the third, a vertical pendulum for recording vertical displacements, is necessary and sufficient. to resolve the issue of the location of the epicentral area and the nature of the earthquake that occurred. Unfortunately, most seismic stations are only supplied with instruments to measure horizontal components. The general organizational structure of the seismic service in the USSR is as follows. At the head of the whole business is the Seismic Institute, which is part of the USSR Academy of Sciences in Leningrad. The latter directs the scientific and practical activities of observation points - seismic observatories and various stations located in certain regions of the country and making observations according to a specific program. The Central Seismic Observatory in Pulkovo, on the one hand, is engaged in the production of regular and continuous observations of all three components of the movement of the earth's crust by means of several series of recorders, on the other hand, it carries out a comparative study of devices and methods for processing seismograms. In addition, on the basis of our own study and experience, other stations of the seismic network are instructed here. In accordance with such an important role that this observatory plays in studying the country in seismic terms, it has a specially arranged underground pavilion so that all external effects - temperature changes, fluctuations of the building under the influence of wind blows, etc. - are eliminated. One of the halls of this pavilion is isolated from the walls and floor of the common building and the most important series of devices of very high sensitivity are located in it. In the practice of modern seismometry, instruments designed by academician B. B. Golitsyn are of great importance. In these devices, the movement of the pendulums can be registered not mechanically, but with the help of the so-called galvanometric registration, at which there is a change in the electrical state in the coil moving with the seismograph pendulum in the magnetic field of a strong magnet. Each coil is connected by wires to a galvanometer, the needle of which oscillates with the movement of the pendulum. A mirror, attached to the galvanometer needle, allows you to follow the changes in the device, either directly or by means of photographic registration. T. about. there is no need to enter a room with devices and thus disturb the balance in the devices by air currents. With this setup, the instruments can be very sensitive. In addition to those indicated, seismographs with mechanical registration... Their design is rougher, the sensitivity is much lower, and with the help of these devices it is possible to control, and most importantly, restore records of high-sensitivity devices in case of various kinds of failures. At the central observatory, in addition to ongoing work, numerous special studies of scientific and applied significance are also carried out.

Observatories or stations of the 1st category are intended for recording distant earthquakes. They are equipped with devices of sufficiently high sensitivity, and in most cases one set of devices is installed on them for the three components of the earth's motion. Synchronous recording of the readings of these instruments makes it possible to determine the angle of exit of seismic rays, and from the records of the vertical pendulum, it is possible to solve the question of the nature of the wave, that is, to determine when a compression or rarefaction wave is approaching. Some of these stations still have instruments for mechanical recording, that is, less sensitive. A number of stations, in addition to general ones, are engaged in solving local issues of significant practical importance, for example, in Makeyevka (Donbass), according to instrument records, one can find a connection between seismic events and firedamp emissions; installations in Baku make it possible to determine the effect of seismic phenomena on the regime of oil sources, etc. All these observatories publish independent bulletins, in which, in addition to general information about the position of the station and about instruments, information about earthquakes is given, indicating the times of the onset of waves of various orders, successive maxima in the main phase, secondary maxima, etc. In addition, data on the soil's own displacements during earthquakes are reported.

Finally seismic observation points of the 2nd category are intended to record earthquakes not particularly distant or even local. In view of this station, these are located Ch. arr. in seismic areas, such as the Caucasus, Turkestan, Altai, Baikal, the Kamchatka Peninsula and Sakhalin Island in our Union. These stations are equipped with heavy pendulums with mechanical registration, have special semi-underground type pavilions for installations; they determine the moments of onset of primary, secondary and long waves, as well as the distance to the epicenter. All these seismic observatories also serve as a time service, since instrument observations are evaluated with an accuracy of a few seconds.

Of the other questions that special observatories are concerned with, let us point out the study of lunisolar attraction, i.e., the tidal movements of the earth's crust, analogous to the phenomena of ebb and flow observed in the sea. For these observations, among other things, a special observatory was built inside the hill near Tomsk, and there are 4 horizontal pendulums of the Zellner system in 4 different azimuths. With the help of special seismic installations, observations were made over the vibrations of the walls of buildings under the influence of diesel engines, observations of the vibrations of the abutments of bridges, especially railway ones, while trains were moving along them, observations of the regime of mineral springs, etc. Recently, seismic observatories have been undertaking special expeditionary observations in in order to study the location and distribution of underground layers, which is of great importance in prospecting for minerals, especially if these observations are accompanied by gravimetric work. Finally, an important expeditionary work of seismic observatories is the production of high-precision leveling in areas subject to significant seismic events, because repeated work in these areas makes it possible to accurately determine the magnitude of horizontal and vertical displacements that occurred as a result of one or another earthquake, and to predict further displacements and earthquake phenomena.

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 polar lights;

- 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 maximum material for research.


Meteorological - all over the world; astronomical - in the mountains (where 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 amount 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 instrument making workshops, a chemical laboratory, a storage of books and documents, and even a printing press for its 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 Parisian Royal, 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, 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 (ability to collect light).

Arecibo - located in Puerto Rico and owns a radio telescope (305 m) with one of the world's largest apertures.

Tokyo University Observatory (Atacama) - the highest on Earth, located at the top of Mount Cerro Chinantor.

Astronomical observatories (in astronomy). Description of observatories in antiquity and in the modern world.

The Astronomical Observatory is a scientific institution designed to observe celestial bodies. It is built on a high place from which you can look anywhere. All observatories are necessarily equipped with telescopes and similar equipment for astronomical and geophysical observations.

1. Astronomical "observatories" in antiquity.
Since ancient times, people have settled down on hills or high terrain for astronomical observations. The pyramids were also used for observation.

Not far from the Karnak fortress, which is located in the city of Luxor, there is the Ra - Gorakhte sanctuary. On the day of the winter solstice, the sunrise was observed from there.
The most ancient prototype of the astronomical observatory is the famous Stonehenge. There is an assumption that in a number of parameters it corresponded to the rising of the Sun on the days of the summer solstice.
2. The first astronomical observatories.
Already in 1425, near Samarkand, the construction of one of the first observatories was completed. It was unique, since it had never been found anywhere else.
Later, the Danish king took an island near Sweden to create an astronomical observatory. Two observatories were built. And for 21 years, the king's activities continued on the island, during which people learned more and more about what the universe is.
3. Observatories of Europe and Russia.
Observatories soon began to be created in Europe. One of the first was the observatory in Copenhagen.
One of the most magnificent observatories of the time was built in Paris. The best scientists work there.
The Royal Greenwich Observatory owes its popularity to the fact that the "Greenwich meridian" passes through the axis of the transit instrument. It was founded by order of the ruler Charles II. The construction was justified by the need to measure the longitude of a place during navigation.
After the construction of the Paris and Greenwich observatories, state observatories began to be created in many other European countries. More than 100 observatories began to operate. They operate in almost every educational institution, and the number of private observatories is growing.
The observatory of the Petersburg Academy of Sciences was among the first to be built. In 1690 on the Northern Dvina, near Arkhangelsk, the fundamental astronomical observatory in Russia was created. In 1839, another observatory was opened - Pulkovo. The Pulkovo Observatory was and is of the greatest importance in comparison with others. The Astronomical Observatory of the St. Petersburg Academy of Sciences was closed, and its numerous instruments and instruments were transported to Pulkovo.
The beginning of a new stage in the development of astronomical science refers to the establishment of the Academy of Sciences.
With the collapse of the USSR, the cost of research development decreases. Because of this, observatories not connected with the state, equipped with professional equipment, are beginning to appear in the country.

Details Category: The work of astronomers Published on 11.10.2012 17:13 Hits: 8741

The Astronomical Observatory is a research institution in which systematic observations of celestial bodies and phenomena are conducted.

Usually the observatory is erected on an elevated area, where a good horizon opens up. The observatory is equipped with observation instruments: optical and radio telescopes, instruments for processing observation results: astrographs, spectrographs, astrophotometers and other devices for characterizing celestial bodies.

From the history of the observatory

It is difficult even to name the time when the first observatories appeared. Of course, these were primitive structures, but nevertheless, observations of the heavenly bodies were carried out in them. The most ancient observatories are located in Assyria, Babylon, China, Egypt, Persia, India, Mexico, Peru and other states. The ancient priests, in fact, were the first astronomers, because they observed the starry sky.
- an observatory created in the Stone Age. It is located near London. This structure was both a temple and a place for astronomical observations - the interpretation of Stonehenge as a grand observatory of the Stone Age belongs to J. Hawkins and J. White. Assumptions that this is the oldest observatory is based on the fact that its stone slabs are installed in a specific order. It is generally known that Stonehenge was the sacred place of the Druids - representatives of the priestly caste among the ancient Celts. Druids were very well versed in astronomy, for example, in the structure and movement of stars, the size of the Earth and planets, and various astronomical phenomena. Science does not know where they got this knowledge. It is believed that they inherited them from the true builders of Stonehenge and, thanks to this, possessed great power and influence.

One more ancient observatory was found on the territory of Armenia, built about 5 thousand years ago.
In the 15th century in Samarkand, the great astronomer Ulugbek built an observatory, outstanding for its time, in which the main instrument was a huge quadrant for measuring the angular distances of stars and other luminaries (read about this on our website: http: //site/index.php/earth/rabota-astrnom/10-etapi- astronimii / 12-sredneverovaya-astronomiya).
The first observatory in the modern sense of the word was the famous museum in Alexandriahosted by Ptolemy II Philadelphus. Aristille, Timocharis, Hipparchus, Aristarchus, Eratosthenes, Geminus, Ptolemy and others have achieved unprecedented results here. This is where the use of tools with split circles began for the first time. Aristarchus established a copper circle in the equatorial plane and with its help observed directly the times of the passage of the Sun through the equinox points. Hipparchus invented the astrolabe (an astronomical instrument based on the principle of stereographic projection) with two mutually perpendicular circles and diopters for observation. Ptolemy introduced the quadrants and set them up with a plumb line. The transition from full circles to quadrants was, in essence, a step back, but the authority of Ptolemy kept the quadrants at observatories until the time of Röhmer, who proved that observations were made more accurately in full circles; however, the quadrants were completely abandoned only at the beginning of the 19th century.

The first observatories of a modern type began to be built in Europe after the telescope was invented - in the 17th century. The first large state observatory - parisian... It was built in 1667. Along with the quadrants and other instruments of ancient astronomy, large refractor telescopes were already used here. In 1675 opened Greenwich Royal Observatory in England, on the outskirts of London.
More than 500 observatories work in the world.

Russian observatories

The first observatory in Russia was the private observatory of A.A. Lyubimov in Kholmogory, Arkhangelsk region, opened in 1692. In 1701, by decree of Peter I, an observatory was created at the Navigation School in Moscow. In 1839, the Pulkovo Observatory near St. Petersburg was founded, equipped with the most sophisticated instruments that made it possible to obtain high-precision results. For this, the Pulkovo Observatory was named the astronomical capital of the world. Now in Russia there are more than 20 astronomical observatories, among them the leading one is the Main (Pulkovo) Astronomical Observatory of the Academy of Sciences.

Observatories of the world

Among foreign observatories, the largest are Greenwich (Great Britain), Harvard and Mount Palomar (USA), Potsdam (Germany), Krakow (Poland), Byurakan (Armenia), Vienna (Austria), Crimean (Ukraine), etc. Observatories of various countries exchange the results of observations and research, often work according to the same program to generate the most accurate data.

Arrangement of observatories

For modern observatories, a typical view is a cylindrical or multifaceted building. These are the towers in which the telescopes are installed. Modern observatories are equipped with optical telescopes housed in closed domed buildings, or radio telescopes. The light radiation collected by telescopes is recorded by photographic or photoelectric methods and analyzed to obtain information on distant astronomical objects. Observatories are usually located far from cities, in climatic zones with low cloud cover and, if possible, on high plateaus, where atmospheric turbulence is negligible and infrared radiation absorbed by the lower atmosphere can be studied.

Observatory types

There are specialized observatories that work according to a narrow scientific program: radio astronomy, mountain stations for observing the Sun; some observatories are associated with observations made by astronauts from spacecraft and orbital stations.
Most of the infrared and ultraviolet range, as well as X-rays and gamma rays of cosmic origin, are inaccessible to observations from the Earth's surface. In order to study the Universe in these rays, it is necessary to take out the observing instruments into space. Until recently, extra-atmospheric astronomy was not available. Now it has become a rapidly growing branch of science. The results obtained with space telescopes, without the slightest exaggeration, turned over many of our ideas about the Universe.
The modern space telescope is a unique set of instruments developed and operated by several countries for many years. Thousands of astronomers from all over the world take part in observations at modern orbiting observatories.

The picture shows the project of the largest infrared optical telescope at the European Southern Observatory with a height of 40 m.

The successful operation of a space observatory requires the joint efforts of various specialists. Space engineers prepare the telescope for launch, put it into orbit, and monitor the power supply of all instruments and their normal functioning. Each object can be observed for several hours, so it is especially important to keep the orientation of the satellite orbiting the Earth in the same direction so that the axis of the telescope remains strictly aimed at the object.

Infrared Observatories

To carry out infrared observations, a rather large load has to be sent into space: the telescope itself, devices for processing and transmitting information, a cooler, which should protect the IR receiver from background radiation - infrared quanta emitted by the telescope itself. Therefore, in the entire history of space flights, very few infrared telescopes have operated in space. The first infrared observatory was launched in January 1983 as part of the joint US-European IRAS project. In November 1995, the European Space Agency launched the ISO infrared observatory into low-earth orbit. It has a telescope with the same mirror diameter as on the IRAS, but more sensitive detectors are used to register the radiation. A wider infrared spectrum is available for ISO observations. Several more space infrared telescope projects are under development and will be launched in the coming years.
Interplanetary stations cannot do without IR equipment.

Ultraviolet observatories

Ultraviolet radiation from the Sun and stars is almost completely absorbed by the ozone layer of our atmosphere, so UV quanta can be recorded only in the upper atmosphere and beyond.
For the first time, an ultraviolet reflector telescope with a mirror diameter (SO cm and a special ultraviolet spectrometer were launched into space on the joint American-European satellite Copernicus, launched in August 1972. Observations were carried out on it until 1981.
Currently, work is underway in Russia to prepare for the launch of a new ultraviolet telescope Spectr-UF with a mirror diameter of 170 cm. The large international project Spectr-UF - World Space Observatory (WCO-UF) is aimed at exploring the Universe inaccessible to observations with ground-based instruments in the ultraviolet (UV) section of the electromagnetic spectrum: 100-320 nm.
The project is led by Russia and is included in the Federal Space Program for 2006-2015. Currently, Russia, Spain, Germany and Ukraine are participating in the project. Kazakhstan and India are also showing interest in participating in the project. The Institute of Astronomy of the Russian Academy of Sciences is the head scientific organization of the project. The lead organization for the rocket and space complex is NPO named after S.A. Lavochkin.
The main instrument of the observatory is being created in Russia - a space telescope with a main mirror 170 cm in diameter. The telescope will be equipped with high and low resolution spectrographs, a spectrograph with a long slit, as well as cameras for creating high-quality images in the UV and optical spectral regions.
In terms of capabilities, the VKO-UV project is comparable to the American Hubble Space Telescope (KTKh) and even surpasses it in spectroscopy.
EKO-UV will open up new possibilities for planetary research, stellar, extragalactic astrophysics and cosmology. The launch of the observatory is scheduled for 2016.

X-ray observatories

X-rays bring us information about powerful cosmic processes associated with extreme physical conditions. The high energy of X-ray and gamma quanta makes it possible to register them "by the piece", with an accurate indication of the registration time. X-ray detectors are relatively easy to manufacture and light in weight. Therefore, they were used for observations in the upper atmosphere and beyond using high-altitude rockets even before the first launches of artificial earth satellites. X-ray telescopes have been installed on many orbital stations and interplanetary spacecraft. In total, about a hundred of these telescopes have visited near-earth space.

Gamma Observatory

Gamma radiation is closely adjacent to X-ray radiation, so similar methods are used to register it. Very often, on telescopes launched into near-earth orbits, both X-ray and gamma sources are studied simultaneously. Gamma rays bring to us information about the processes taking place inside atomic nuclei, and about the transformations of elementary particles in space.
The first observations of cosmic gamma sources were classified. In the late 60s - early 70s. The United States has launched four Vela-series military satellites. The equipment of these satellites was developed to detect bursts of hard X-ray and gamma radiation that occur during nuclear explosions. However, it turned out that most of the recorded bursts are not related to military tests, and their sources are not located on Earth, but in space. This is how one of the most mysterious phenomena in the Universe was discovered - gamma-ray bursts, which are single powerful bursts of hard radiation. Although the first cosmic gamma-ray bursts were recorded back in 1969, information about them was published only four years later.