Astronomical observations on earth or in space. Structure and scales of the Universe. Observations of lunar eclipses

Astronomy is one of the oldest sciences. From time immemorial, people have followed the movement of the stars across the sky. Astronomical observations of that time helped to navigate the terrain, and were also necessary for the construction of philosophical and religious systems. A lot has changed since then. Astronomy finally freed itself from astrology, accumulated extensive knowledge and technical power. However, astronomical observations made on Earth or in space are still one of the main methods of obtaining data in this science. The methods of collecting information have changed, but the essence of the methodology has remained unchanged.

What are astronomical observations?

There is evidence to suggest that people possessed elementary knowledge about the movement of the Moon and the Sun even in the prehistoric era. The works of Hipparchus and Ptolemy testify that knowledge about the luminaries was also in demand in Antiquity, and much attention was paid to them. For that time and for a long period after, astronomical observations were the study of the night sky and the fixation of what was seen on paper, or, more simply, a sketch.

Until the Renaissance, only the simplest instruments were assistants to scientists in this matter. A significant amount of data became available after the invention of the telescope. As it improved, the accuracy of the information received increased. However, at whatever level of technological progress, astronomical observations are the main way to collect information about celestial objects. Interestingly, this is also one of the areas of scientific activity in which the methods used in the era before scientific progress, that is, observation with the naked eye or with the help of the simplest equipment, have not lost their relevance.

Classification

Today, astronomical observations are a fairly broad category of activities. They can be classified according to several criteria:

• qualifications of the participants;
• the nature of the recorded data;
• location.

In the first case, professional and amateur observations are distinguished. The data obtained in this case is most often the registration of visible light or other electromagnetic radiation, including infrared and ultraviolet. In this case, information can be obtained in some cases only from the surface of our planet or only from space outside the atmosphere: according to the third feature, astronomical observations made on Earth or in space are distinguished.

amateur astronomy

The beauty of the science of the stars and other celestial bodies is that it is one of the few that literally needs active and tireless admirers among non-professionals. A huge number of objects worthy of constant attention, there are a small number of scientists occupied with the most complex issues. Therefore, astronomical observations of the rest of the near space fall on the shoulders of amateurs.

The contribution of people who consider astronomy their hobby to this science is quite tangible. Until the middle of the last decade of the last century, more than half of the comets were discovered by amateurs. Their areas of interest also often include variable stars, observing novae, tracking the coverage of celestial bodies by asteroids. The latter is today the most promising and demanded work. As for New and Supernovae, as a rule, amateur astronomers are the first to notice them.

Options for non-professional observations

Amateur astronomy can be divided into closely related branches:

• Visual astronomy. This includes astronomical observations with binoculars, a telescope, or the naked eye. The main goal of such activities, as a rule, is to enjoy the opportunity to observe the movement of the stars, as well as from the process itself. An interesting branch of this direction is "sidewalk" astronomy: some amateurs take their telescopes out into the street and invite everyone to admire the stars, planets and the Moon.
• Astrophotography. The purpose of this direction is to obtain photographic images of celestial bodies and their elements.
• Telescope building. Sometimes the necessary optical instruments, telescopes and accessories for them, are made by amateurs almost from scratch. In most cases, however, telescope construction consists in supplementing existing equipment with new components.
• Research. Some amateur astronomers seek, in addition to aesthetic pleasure, to get something more material. They are engaged in the study of asteroids, variables, new and supernovae, comets and meteor showers. Periodically, in the process of constant and painstaking observations, discoveries are made. It is this activity of amateur astronomers that makes the greatest contribution to science.

Activities of professionals

Specialist astronomers around the world have more sophisticated equipment than amateurs. The tasks facing them require high accuracy in collecting information, a well-functioning mathematical apparatus for interpretation and forecasting. As a rule, quite complex, often distant objects and phenomena lie at the center of the work of professionals. Often, the study of the expanses of space makes it possible to shed light on certain laws of the universe, to clarify, supplement or refute theoretical constructions regarding its origin, structure and future.

Classification by type of information

Observations in astronomy, as already mentioned, can be associated with the fixation of various radiation. On this basis, the following directions are distinguished:

• optical astronomy studies radiation in the visible range;
• infrared astronomy;
• ultraviolet astronomy;
• radio astronomy;
• x-ray astronomy;
• gamma astronomy.

In addition, the directions of this science and the corresponding observations that are not related to electromagnetic radiation are highlighted. This includes neutrino, studying neutrino radiation from extraterrestrial sources, gravitational-wave and planetary astronomy.

From the surface

Some of the phenomena studied in astronomy are available for research in ground-based laboratories. Astronomical observations on Earth are associated with the study of the trajectories of the movement of celestial bodies, measuring the distance in space to stars, fixing certain types of radiation and radio waves, and so on. Until the beginning of the era of astronautics, astronomers could only be content with information obtained under the conditions of our planet. And this was enough to build a theory of the origin and development of the Universe, to discover many patterns that exist in space.

High above the earth

With the launch of the first satellite, a new era in astronomy began. The data collected by spacecraft is invaluable. They contributed to the deepening of scientists' understanding of the mysteries of the universe.

Astronomical observations in space make it possible to detect all types of radiation, from visible light to gamma and X-rays. Most of them are not available for research from the Earth, because the atmosphere of the planet absorbs them and does not allow them to the surface. An example of discoveries that became possible only after the start of the space age are X-ray pulsars.

Information miners

Astronomical observations in space are carried out using various equipment installed on spacecraft and orbiting satellites. Many studies of this nature are being carried out on the International Space Station. The contribution of optical telescopes launched several times in the last century is invaluable. The famous Hubble stands out among them. For the layman, it is primarily a source of stunningly beautiful photographic images of deep space. However, this is not all that he "can do". With its help, a large amount of information about the structure of many objects, the patterns of their "behavior" was obtained. Hubble and other telescopes are an invaluable source of data necessary for theoretical astronomy, working on the problems of the development of the universe.

Astronomical observations - both terrestrial and space - are the only ones for the science of celestial bodies and phenomena. Without them, scientists could only develop various theories without being able to compare them with reality.

Among the methods of astronomy, otherwise the methods of astronomical research, three main groups can be distinguished:

• observation,
• measurement,
• space experiment.

Let's take a look at these methods.

Astronomical observations

Remark 1

Astronomical observations are the main way to study celestial bodies and events. It is with their help that what is happening in near and far space is recorded. Astronomical observations are the main source of knowledge obtained experimentally

Astronomical observations and processing of their data, as a rule, are carried out in specialized research institutions (astronomical observatories).

The first Russian observatory was built at Pulkovo, near St. Petersburg. The compilation of star catalogs of stars with the highest accuracy is the merit of the Pulkovo Observatory. We can say that in the second half of the 19th century, behind the scenes, she was awarded the title of "astronomical capital of the world", and in 1884 Pulkovo claimed the zero meridian (Greenwich won).

Modern observatories are equipped with observation instruments (telescopes), light-receiving and analyzing equipment, various auxiliary devices, high-performance computers, and so on.

Let us dwell on the features of astronomical observations:

• Feature #1. Observations are very inert, therefore, as a rule, they require rather long periods of time. Active influence on space objects, with rare exceptions that are provided by manned and unmanned astronautics, is difficult. Basically, many phenomena, for example, the transformation of the angle of inclination of the Earth's axis to the orbital plane, can only be recorded through observations over several thousand years. Consequently, the astronomical heritage of Babylon and China of a thousand years ago, despite some inconsistencies with modern requirements, is still relevant.
• Feature #2. The process of observation, as a rule, takes place from the earth's surface, at the same time the earth carries out a complex movement, so the earthly observer sees only a certain part of the starry sky.
• Feature number 3. Angular measurements performed on the basis of observations are the basis for calculations that determine the linear dimensions of objects and the distances to them. And since the angular sizes of stars and planets, measured using optics, do not depend on the distance to them, the calculations can be quite inaccurate.

Remark 2

The main instrument of astronomical observations is an optical telescope.

An optical telescope has a principle of operation determined by its type. But regardless of the type, its main goal and task is to collect the maximum amount of light emitted by luminous objects (stars, planets, comets, etc.) to create their images.

Types of optical telescopes:

• refractors (lens),
• reflectors (mirror),
• as well as mirror lenses.

In a refractor (lens) telescope, the image is achieved by the refraction of light in the objective lens. The disadvantage of refractors is an error resulting from blurring the image.

A feature of reflectors is their use in astrophysics. In them, the main thing is not how light is refracted, but how it is reflected. They are more perfect than lenses, and more accurate.

Mirror-lens telescopes combine the functions of refractors and reflectors.

Figure 1. Small optical telescope. Author24 - online exchange of student papers

Astronomical measurements

Since measurements in astronomical research are carried out using various instruments and instruments, we will briefly review them.

Remark 3

The main astronomical measuring instruments are coordinate measuring machines.

These machines measure one or two rectangular coordinates from a photographic image or spectrum diagram. Coordinate measuring machines are equipped with a table on which photographs are placed and a microscope with measuring functions used to aim at a luminous body or its spectrum. Modern devices can have a readout accuracy of up to 1 micron.

Errors may occur during the measurement process:

• the instrument itself
• operator (human factor),
• arbitrary.

Instrument errors arise from its imperfection, therefore, its accuracy must be checked beforehand. In particular, the following are subject to verification: scales, micrometric screws, guides on the object table and the measuring microscope, reference micrometers.

Errors associated with the human factor and randomness are stopped by the multiplicity of measurements.

In astronomical measurements, there is a widespread introduction of automatic and semi-automatic measuring instruments.

Automatic devices work an order of magnitude faster than conventional ones, and have half the mean square error.

space experiment

Definition 1

A space experiment is a set of interconnected interactions and observations that make it possible to obtain the necessary information about the studied celestial body or phenomenon, carried out in a space flight (manned or unmanned) in order to confirm theories, hypotheses, as well as improve various technologies that can contribute to development of scientific knowledge.

The main trends of experiments in space:

1. The study of the course of physical and chemical processes and the behavior of materials in outer space.
2. The study of the properties and behavior of celestial bodies.
3. The influence of space on man.
4. Confirmation of theories of space biology and biotechnology.
5. Ways of space exploration.

Here it is appropriate to give examples of experiments carried out on the ISS by Russian cosmonauts.

Plant Growth Experiment (Veg-01).

The objective of the experiment is to study the behavior of plants in orbital conditions.

Experiment "Plasma Crystal"- study of plasma-dust crystals and liquid substances under microgravity parameters.

Four stages were carried out:

1. The plasma-dust structure in a gas-discharge plasma at a high-frequency capacitive discharge was studied.
2. The plasma-dust structure in a plasma was studied in a glow discharge with direct current.
3. It was investigated how the ultraviolet spectrum of cosmic radiation affects macroparticles, which can be charged with photoemission.
4. Plasma-dust structures were studied in open space under the action of solar ultraviolet and ionizing radiation.

Figure 2. Experiment "Plasma Crystal". Author24 - online exchange of student papers

In total, more than 100 space experiments were carried out by Russian cosmonauts on the ISS.

The main way to study celestial objects and phenomena. Observations can be made with the naked eye or with the help of optical instruments: telescopes equipped with various radiation receivers (spectrographs, photometers, etc.), astrographs, special instruments (in particular, binoculars). The purposes of observations are very diverse. Precise measurements of the positions of stars, planets, and other celestial bodies provide material for determining their distances (see Parallax), the proper motions of stars, and studying the laws of motion of planets and comets. The results of measurements of the visible brightness of the luminaries (visually or with the help of astrophotometers) make it possible to estimate the distances to stars, star clusters, galaxies, to study the processes occurring in variable stars, etc. Studies of the spectra of celestial bodies with the help of spectral instruments make it possible to measure the temperature of the luminaries, radial velocities, and provide invaluable material for a deep study of the physics of stars and other objects.

But the results of astronomical observations are of scientific significance only when the provisions of the instructions that determine the procedure for the observer, the requirements for instruments, the place of observation, and the form of registration of observation data are unconditionally fulfilled.

Observation methods available to young astronomers include visual without instruments, visual telescopic, photographic and photoelectric observation of celestial objects and phenomena. Depending on the instrumental base, the location of 1 observation points (city, town, village), 1 climatic conditions and the interests of an amateur, any (or several) of the proposed topics can be chosen for observations.

Observations of solar activity. When observing solar activity, sunspots are drawn daily and their coordinates are determined using a pre-prepared goniometric grid. It is best to make observations using a large school refractor telescope or a homemade telescope on a parallactic tripod (see Homemade telescope). You must always remember that you should never look at the Sun without a dark (protective) filter. It is convenient to observe the Sun by projecting its image onto a screen specially adapted to the telescope. On a paper template, outline the contours of groups of spots and individual spots, mark the pores. Then their coordinates are calculated, the number of sunspots in groups is counted, and at the time of observations, the index of solar activity, the Wolf number, is displayed. The observer also studies all the changes that occur within a group of spots, trying to convey their shape, size, and relative position of details as accurately as possible. The Sun can also be observed photographically with the use of additional optics in the telescope, which increases the equivalent focal length of the instrument and therefore makes it possible to photograph larger individual formations on its surface. Plates and films for photographing the Sun should have the lowest possible sensitivity.

Observations of Jupiter and its satellites. When observing planets, in particular Jupiter, a telescope with a lens or mirror diameter of at least 150 mm is used. The observer carefully sketches the details in Jupiter's bands and the bands themselves and determines their coordinates. By making observations over a number of nights, one can study the pattern of changes in the cloud cover of the planet. Interesting to observe on the disk of Jupiter is the Red Spot, the physical nature of which has not yet been fully studied. The observer draws the position of the Red Spot on the planet's disk, determines its coordinates, gives descriptions of the color, brightness of the spot, and registers the noticed features in the cloud layer surrounding it.

To observe the moons of Jupiter, a school refractor telescope is used. The observer determines the exact position of the satellites relative to the edge of the planet's disk using an ocular micrometer. In addition, it is of interest to observe phenomena in a system of satellites and to record the moments of these phenomena. These include the eclipse of the satellites, the entry and exit from the disk of the planet, the passage of the satellite between the Sun and the planet, between the Earth and the planet.

Search for comets and their observations. Searches for comets are carried out using high-aperture optical instruments with a large field of view (3-5 °). Field binoculars, AT-1 astronomical tube, TZK, BMT-110 binoculars, as well as comet detectors can be used for this purpose.

The observer systematically examines the western part of the sky after sunset, the northern and zenith regions of the sky at night, and the eastern part before sunrise. The observer must know very well the location in the sky of stationary nebulous objects - gaseous nebulae, galaxies, star clusters, which in appearance resemble a comet with a faint brightness. In this case, he will be assisted by atlases of the starry sky, in particular, A. D. Marlensky’s “Educational Star Atlas” and A. A. Mikhailov’s “Star Atlas”. About the appearance of a new comet, a telegram is immediately sent to the Astronomical Institute named after PK Sternberg in Moscow. It is necessary to report the time of detection of the comet, its approximate coordinates, the name and surname of the observer, his postal address.

The observer must draw the position of the comet among the stars, study the visible structure of the comet's head and tail (if any), and determine its brilliance. Photographing the region of the sky where the comet is located makes it possible to determine its coordinates more accurately than when sketching, and, consequently, to calculate the comet's orbit more accurately. When photographing a comet, the telescope must be equipped with a clock mechanism that leads it behind the stars moving due to the apparent rotation of the sky.

Observations of noctilucent clouds. Noctilucent clouds are the most interesting, but still little-studied phenomenon of nature. In the USSR they are observed in summer north of 50° latitude. They can be seen against the background of the twilight segment, when the angle of the Sun's immersion under the horizon is from 6 to 12°. At this time, the sun's rays illuminate only the upper layers of the atmosphere, where noctilucent clouds form at an altitude of 70-90 km. Unlike ordinary clouds, which appear dark at dusk, noctilucent clouds glow. They are observed in the northern side of the sky, not high above the horizon.

The observer every night examines the twilight segment at 15-minute intervals and, in the event of the appearance of noctilucent clouds, evaluates their brightness, registers changes in shape, and using a theodolite or other goniometric instrument measures the length of the cloud field in height and azimuth. In addition, it is advisable to photograph noctilucent clouds. If the lens aperture is 1:2 and the film sensitivity is 130-180 units according to GOST, then good pictures can be obtained with an exposure of 1-2 s. The image should show the main part of the cloud field and silhouettes of buildings or trees.

The purpose of patrolling the twilight segment and observing noctilucent clouds is to determine the frequency of occurrence of clouds, the prevailing forms, the dynamics of the field of noctilucent clouds, as well as individual formations within the cloud field.

Meteor observations. The tasks of visual observations are to count meteors and determine meteor radiants. In the first case, the observers are positioned under a circular frame that limits the field of view to 60° and register only those meteors that appear inside the frame. The observation log records the serial number of the meteor, the moment of passage with an accuracy of one second, the magnitude, angular velocity, direction of the meteor and its position relative to the frame. These observations make it possible to study the density of meteor showers and the brightness distribution of meteors.

When determining meteor radiants, the observer carefully marks each observed meteor on a copy of the starry sky map and notes the meteor's serial number, moment of passage, magnitude, meteor length in degrees, angular velocity and color. Weak meteors are observed with the help of field glasses, AT-1 tubes, TZK binoculars. Observations under this program make it possible to study the distribution of small radiants on the celestial sphere, determine the position and displacement of the studied small radiants, and lead to the discovery of new radiants.

Observations of variable stars. The main instruments for observing variable stars: field binoculars, AT-1 astronomical tubes, TZK binoculars, BMT-110, comet detectors that provide a large field of view. Observations of variable stars make it possible to study the laws of change in their brightness, to specify the periods and amplitudes of change in brightness, to determine their type, and so on.

Initially, variable stars are observed - Cepheids, which have regular brightness fluctuations with a sufficiently large amplitude, and only after that one should proceed to observations of semi-regular and irregular variable stars, stars with a small brightness amplitude, as well as investigate stars suspected of variability, and patrol flaring stars.

With the help of cameras, you can photograph the starry sky in order to observe long-term variable stars and search for new variable stars.

Observations of solar eclipses

The program of amateur observations of a total solar eclipse may include: visual registration of the moments of contact between the edge of the Moon's disk and the edge of the Sun's disk (four contacts); sketches of the appearance of the solar corona - its shape, structure, size, color; telescopic observations of phenomena when the edge of the lunar disk covers sunspots and flares; meteorological observations - registration of the course of temperature, pressure, air humidity, changes in direction and strength of the wind; observing the behavior of animals and birds; photographing partial phases of the eclipse through a telescope with a focal length of 60 cm or more; photographing the solar corona using a camera with a lens having a focal length of 20-30 cm; photographing the so-called Bailey's rosary, which appears before the outbreak of the solar corona; registration of changes in the brightness of the sky as the phase of the eclipse increases with a homemade photometer.

Observations of lunar eclipses

Like solar eclipses, lunar eclipses occur relatively rarely, and at the same time, each eclipse is characterized by its own characteristics. Observations of lunar eclipses make it possible to refine the orbit of the moon and provide information about the upper layers of the earth's atmosphere. A lunar eclipse observation program may consist of the following elements: determination of the brightness of the shadowed parts of the lunar disk from the visibility of the details of the lunar surface when observed through 6x recognized binoculars or a telescope with low magnification; visual estimates of the brightness of the Moon and its color both with the naked eye and with binoculars (telescope); observations through a telescope with a lens diameter of at least 10 cm at 90x magnification throughout the eclipse of the craters Herodotus, Aristarchus, Grimaldi, Atlas and Riccioli, in the area of ​​which color and light phenomena can occur; registration with a telescope of the moments of covering by the earth's shadow of some formations on the lunar surface (the list of these objects is given in the book "Astronomical calendar. Permanent part"); determination using a photometer of the brightness of the surface of the moon at various phases of the eclipse.

Observations of artificial Earth satellites

When observing artificial satellites of the Earth, the path of the satellite on the star map and the time of its passage around noticeable bright stars are noted. Time must be recorded to the nearest 0.2 s using a stopwatch. Bright satellites can be photographed.

Astronomy is based on observations made from the Earth and only since the 60s of our century, carried out from space - from automatic and other space stations, and even from the Moon. The devices made it possible to obtain samples of lunar soil, deliver various instruments, and even land people on the moon. But for the time being, only the celestial bodies closest to the Earth can be explored. Playing the same role as experiments in physics and chemistry, observations in astronomy have a number of features.

First Feature consists in the fact that astronomical observations are in most cases passive in relation to the objects under study. We cannot actively influence celestial bodies, perform experiments (with the exception of rare cases), as is done in physics, biology, and chemistry. Only the use of spacecraft has provided some opportunities in this respect.

In addition, many celestial phenomena proceed so slowly that their observation requires enormous periods; for example, a change in the inclination of the earth's axis to the plane of its orbit becomes noticeable only after hundreds of years. Therefore, for us, some observations made in Babylon and in China thousands of years ago have not lost their significance, and they were, according to modern concepts, very inaccurate.

Second feature astronomical observations is as follows. We observe the position of celestial bodies and their movement from the Earth, which itself is in motion. Therefore, the view of the sky for an earthly observer depends not only on where he is on the Earth, but also on what time of day and year he observes. For example, when we have a winter day, in South America it is a summer night, and vice versa. There are stars visible only in summer or winter.

Third feature astronomical observations is due to the fact that all the luminaries are very far from us, so far away that neither by eye nor through a telescope can one decide which of them is closer, which is farther. They all seem equally distant to us. Therefore, during observations, angular measurements are usually performed, and already from them conclusions are often drawn about the linear distances and sizes of bodies.

The distance between objects in the sky (for example, stars) is measured by the angle formed by the rays going to the objects from the point of observation. This distance is called angular and is expressed in degrees and its fractions. In this case, it is considered that two stars are not far from each other in the sky, if the directions in which we see them are close to each other (Fig. 1, stars A and B). It is possible that the third star C, in the sky more distant from L, in space to BUT closer than a star AT.

Measurements of the height, the angular distance of an object from the horizon, are performed with special goniometric optical instruments, such as a theodolite. Theodolite is an instrument, the main part of which is a telescope rotating about the vertical and horizontal axes (Fig. 2). Attached to the axes are circles divided into degrees and minutes of arc. In these circles, the direction of the telescope is counted. On ships and airplanes, angular measurements are made with an instrument called a sextant (sextan).

The apparent dimensions of celestial objects can also be expressed in angular units. The diameters of the Sun and the Moon in angular measure are approximately the same - about 0.5 °, and in linear units the Sun is larger than the Moon in diameter by about 400 times, but it is the same number of times farther from the Earth. Therefore, their angular diameters are almost equal for us.

Your observations

For a better assimilation of astronomy, you should start observing celestial phenomena and luminaries as early as possible. Guidelines for observations with the naked eye are given in Appendix VI. Finding the constellations, orienting yourself on the ground using the Polar Star, familiar to you from the course of physical geography, and observing the daily rotation of the sky is conveniently performed using the moving star map attached to the textbook. For an approximate estimate of the angular distances in the sky, it is useful to know that the angular distance between the two stars of the "dipper" Ursa Major is approximately 5 °.

First of all, you need to get acquainted with the view of the starry sky, find planets on it and make sure that they move relative to the stars or the Sun within 1-2 months. (The conditions for the visibility of planets and some celestial phenomena are discussed in the school astronomical calendar for a given year.) Along with this, one should familiarize oneself with the relief of the Moon, with sunspots, and then with other luminaries and phenomena, which are mentioned in Appendix VI . To do this, an introduction to the telescope is given below.

1. Astronomy is a new discipline in the course, although you are familiar with some of the topics in a nutshell.
2. What do you need:

1. Textbook: . Astronomy. Basic level.11 grade: textbook / B.A. Vorontsov-Velyaminov, E.K. Strout - 5th ed., revised .- M .: Bustard, 2018.-238s, with: ill., 8 sheets. col. incl. - (Russian textbook).;
2. general notebook - 48 sheets.

1. How to work with the textbook.

• work through (rather than read) a paragraph
• to delve into the essence, to deal with each phenomenon and process
• work through all the questions and tasks after the paragraph, briefly in notebooks
• check your knowledge on the list of questions at the end of the topic
• see additional material on the Internet

Topic 1.1 The subject of astronomy. Observations are the basis of astronomy.

1.1.1 What does astronomy study. Its significance and connection with other sciences

Astronomy is one of the oldest sciences, the origins of which date back to the Stone Age (VI-III millennium BC).

Astronomy it is a science that studies the movement, structure, origin and development of celestial bodies and their systems.

Astronomy[Greek Astron (astron) - star, nomos (nomos) - law] - a science that studies the movement of celestial bodies (section "celestial mechanics"), their nature (section "astrophysics"), origin and development (section "cosmogony")

Astronomy, one of the most fascinating and ancient sciences of nature, explores not only the present, but also the distant past of the macroworld around us, and also allows us to draw a scientific picture of the future of the Universe. Man has always been interested in the question of how the world around him works and what place he occupies in it. At the dawn of civilization, most peoples had special cosmological myths that tell how space (order) gradually arises from the initial chaos, everything that surrounds a person appears: heaven and earth, mountains, seas and rivers, plants and animals, as well as the person himself. For thousands of years there has been a gradual accumulation of information about the phenomena that took place in the sky.

The need for astronomical knowledge was dictated by vital necessity (demonstration of films: " All the secrets of space #21 - Discovery - the history of astronomy" and Astronomy (2⁄15). The oldest science.)

It turned out that periodic changes in terrestrial nature are accompanied by changes in the appearance of the starry sky and the apparent movement of the Sun. It was necessary to calculate the onset of a certain time of the year in order to carry out certain agricultural work on time: sowing, watering, harvesting. But this could only be done using a calendar compiled from long-term observations of the position and movement of the Sun and Moon. So the need for regular observations of celestial bodies was due to the practical needs of counting time. The strict periodicity inherent in the movement of heavenly bodies underlies the basic units of time counting that are still used today - day, month, year.

Simple contemplation of occurring phenomena and their naive interpretation were gradually replaced by attempts to scientifically explain the causes of observed phenomena. When in Ancient Greece (VI century BC) the rapid development of philosophy as a science of nature began, astronomical knowledge became an integral part of human culture. Astronomy is the only science that has received its patron muse - Urania.

On the initial significance of the development of astronomical knowledge can be judged in connection with the practical needs of people. They can be divided into several groups:

• agricultural needs(the need for counting time is days, months, years. For example, in ancient Egypt, the time of sowing and harvesting was determined by the appearance before sunrise from behind the edge of the horizon of the bright star Sothis, a harbinger of the Nile flood);
• trade expansion needs, including marine (seafaring, searching for trade routes, navigation. So, the Phoenician sailors were guided by the North Star, which the Greeks called the Phoenician Star);
• aesthetic and cognitive needs, the need for a holistic worldview(man sought to explain the periodicity of natural phenomena and processes, the emergence of the surrounding world).

The origin of astronomy in astrological ideas is characteristic of the mythological worldview of ancient civilizations.

I-th Antique world(BC). Philosophy →astronomy → elements of mathematics (geometry). Ancient Egypt, Ancient Assyria, Ancient Maya, Ancient China, Sumerians, Babylonia, Ancient Greece.

Scientists who have made a significant contribution to the development of astronomy: Thales of Miletus(625-547, Dr. Greece), Eudox of Knidos(408-355, Other Greece), ARISTOTLE(384-322, Macedonia, Other Greece), Aristarchus of Samos(310-230, Alexandria, Egypt), ERATOSPHENES(276-194, Egypt), Hipparchus of Rhodes(190-125, Ancient Greece).

Archaeologists have established that man possessed basic astronomical knowledge already 20 thousand years ago in the Stone Age.

• Prehistoric stage from 25 thousand years BC to 4 thousand BC (rock paintings, natural observatories, etc.).
• The ancient stage can conditionally be considered from 4,000 years BC-1000 BC:
  • about 4 thousand BC astronomical monuments of the ancient Maya, Stonehenge stone observatory (England);
  • about 3000 BC orientation of the pyramids, the first astronomical records in Egypt, Babylon, China;
  • around 2500 BC establishment of the Egyptian solar calendar;
  • around 2000 BC creation of the 1st sky map (China);
  • about 1100 BC determination of the inclination of the ecliptic to the equator;
• antique stage
  • ideas about the sphericity of the Earth (Pythagoras, 535 BC);
  • the prediction of a solar eclipse by Thales of Miletus (585 BC);
  • the establishment of a 19-year cycle of lunar phases (Metonic cycle, 433 BC);
  • ideas about the rotation of the Earth around its axis (Heraclitus of Pontus, 4th century BC);
  • the idea of ​​concentric circles (Eudoxus), the treatise "On the Sky" Aristotle (proof of the sphericity of the Earth and planets) compilation of the first catalog of stars 800 stars, China (4th century BC);
  • the beginning of systematic determinations of the positions of stars by Greek astronomers, the development of the theory of the system of the world (3rd century BC);
  • discovery of precession, the first tables of the motion of the Sun and Moon, a star catalog of 850 stars (Hipparachus, (2nd century BC);
  • the idea of ​​the movement of the Earth around the Sun and determining the size of the Earth (Aristarchus of Samos, Eratosthenes 3-2 centuries BC);
  • the introduction of the Julian calendar into the Roman Empire (46 BC);
  • Claudius Ptolemy - "Syntax" (Almogest) - encyclopedia of ancient astronomy, theory of motion, planetary tables (140 AD).

The poems of Homer and Hesiod give an idea of ​​the astronomical knowledge of the Greeks of this period: a number of stars and constellations are mentioned there, practical advice is given on the use of celestial bodies for navigation and for determining the seasons of the year. The cosmological ideas of this period were entirely borrowed from myths: the Earth is considered flat, and the sky is a solid bowl based on the Earth. The main characters of this period are philosophers, intuitively groping for what will later be called the scientific method of cognition. At the same time, the first specialized astronomical observations are being made, the theory and practice of the calendar is being developed; for the first time, geometry is taken as the basis of astronomy, a number of abstract concepts of mathematical astronomy are introduced; attempts are being made to find physical patterns in the movement of the luminaries. A number of astronomical phenomena were scientifically explained, the sphericity of the Earth was proved.

II Pre-telescopic period. (our era before 1610). The decline of science and astronomy. The collapse of the Roman Empire, the raids of the barbarians, the birth of Christianity. The rapid development of Arabic science. The revival of science in Europe. Modern heliocentric system of world structure.

Claudius Ptolemy (Claudius Ptolomeus)(87-165, Dr. Rome), BIROUNI, Abu Reyhan Mohammed ibn Ahmed al-Biruni(973-1048, modern Uzbekistan), Mirza Mohammed ibn Shahrukh ibn Timur (Taragay) ULUGBEK(1394-1449, modern Uzbekistan), Nicolaus COPERNICK(1473-1543, Poland), Tycho (Tige) BRAGE(1546-1601, Denmark).

• Arabic period. After the fall of the ancient states in Europe, ancient scientific traditions (including astronomy) continued to develop in the Arab caliphate, as well as in India and China.
  • 813 Establishment of an astronomical school (house of wisdom) in Baghdad;
  • 827 determination of the size of the globe by degree measurements between the Tigris and the Euphrates;
  • 829 foundation of the Baghdad Observatory;
  • 10th century the discovery of the lunar inequality (Abu-l-Wafa, Baghdad);
  • catalog of 1029 stars, clarification of the inclination of the ecliptic to the equator, determination of the length of 1° meridian (1031g, Al-Biruni);
  • numerous works on astronomy until the end of the 15th century (calendar of Omar Khayyam, "Ilkhan tables" of the movement of the Sun and planets (Nasiraddin Tussi, Azerbaijan), works of Ulugbek);
• European revival. At the end of the 15th century, a revival of astronomical knowledge began in Europe, which led to the first revolution in astronomy. This revolution in astronomy was caused by the requirements of practice - the era of great geographical discoveries began.
  • Long-distance voyages required precise methods for determining coordinates. The Ptolemaic system could not meet the increased needs. The countries that were the first to pay attention to the development of astronomical research achieved the greatest success in discovering and developing new lands.
  • In Portugal, back in the 14th century, Prince Henry founded an observatory to meet the needs of navigation, and Portugal was the first European country to begin capturing and exploiting new territories.
  • The most important achievements of European astronomy of the XV-XVI centuries are planetary tables (Regiomontanus from Nuremberg, 1474),
  • the works of N. Copernicus, who made the first revolution in Astronomy (1515-1540),
  • observations by the Danish astronomer Tycho Brahe at the Uraniborg observatory on the island of Van (the most accurate in the pre-telescopic era).

III Telescopic before the advent of spectroscopy (1610-1814). The invention of the telescope and observation with it. The laws of planetary motion. Discovery of the planet Uranus. The first theories of the formation of the solar system.

Scientists who made a significant contribution to the development of astronomy in this period: Galileo Galilei(1564-1642, Italy), Johannes KEPLER(1571-1630, Germany), Jan GAVEL (GAVELIUS) (1611-1687, Poland), Hans Christian HUYGENS(1629-1695, Netherlands), Giovanni Domenico (Jean Dominic) CASINI>(1625-1712, Italy-France), Isaac Newton(1643-1727, England), Edmund GALLEY (HALLEY, 1656-1742, England), William (William) Wilhelm Friedrich HERSHEL(1738-1822, England), Pierre Simon Laplace(1749-1827, France).

• At the beginning of the 17th century (Lippershey, Galileo, 1608) an optical telescope was created, which greatly expanded the horizon of mankind's knowledge of the world.
  • the parallax of the Sun is determined (1671), which made it possible to determine the astronomical unit with high accuracy and determine the speed of light,
  • the subtle movements of the Earth's axis, the proper movements of the stars, the laws of the motion of the Moon,
  • in 1609-1618 Kepler, based on these observations of the planet Mars, discovered three laws of planetary motion,
  • in 1687 Newton published the law of universal gravitation, which explains the causes of the motion of the planets.
  • celestial mechanics is created;
  • the masses of the planets are determined;
  • at the beginning of the 19th century (January 1, 1801), Piazzi discovers the first minor planet (asteroid) Ceres;
  • Pallas and Juno were discovered in 1802 and 1804.

IV Spectroscopy and photography. (1814-1900). Spectroscopic observations. The first determination of the distance to the stars. Discovery of the planet Neptune.

Scientists who made a significant contribution to the development of astronomy in this period: Joseph von Fraunhofer(1787-1826, Germany), Vasily Yakovlevich (Friedrich Wilhelm Georg) STRUVE(1793-1864, Germany-Russia), George Biddell ERI(AIRIE, 1801-1892, England), Friedrich Wilhelm BESSEL(1784-1846, Germany), Johann Gottfried HALLE(1812-1910, Germany), William HEGGINS (Huggins, 1824-1910, England), Angelo SECCHI(1818-1878, Italy), Fedor Alexandrovich BREDIKHIN(1831-1904, Russia), Edward Charles Pickering(1846-1919, USA).

• In 1806 - 1817, I. Fraunthofer (Germany) created the foundations of spectral analysis, measured the wavelengths of the solar spectrum and absorption lines, thus laying the foundations of astrophysics.
• In 1845, I. Fizeau and J. Foucault (France) obtained the first photographs of the Sun.
• In 1845 - 1850, Lord Ross (Ireland) discovered the spiral structure of some nebulae.
• in 1846, I. Galle (Germany), according to the calculations of W. Le Verrier (France), discovered the planet Neptune, which was a triumph of celestial mechanics
• The introduction of photography into astronomy made it possible to obtain photographs of the solar corona and the surface of the Moon, and to begin studying the spectra of stars, nebulae, and planets.
• Progress in optics and telescope construction made it possible to discover the satellites of Mars, to describe the surface of Mars by observing it in opposition (D. Schiaparelli)
• Increasing the accuracy of astrometric observations made it possible to measure the annual parallax of stars (Struve, Bessel, 1838), and to discover the movement of the earth's poles.

V-th Modern period (1900-present). Development of the application of photography and spectroscopic observations in astronomy. Solving the problem of the energy source of stars. Discovery of galaxies. The emergence and development of radio astronomy. Space research.

• At the beginning of the 20th century, K.E. Tsiolkovsky published the first scientific essay on astronautics - “The study of world spaces with jet devices”.
• In 1905, A. Einstein creates the special theory of relativity
• in 1907 - 1916, the general theory of relativity, which made it possible to explain the existing contradictions between the existing physical theory and practice, gave impetus to unravel the mystery of the energy of stars, stimulated the development of cosmological theories
• In 1923, E. Hubble proved the existence of other star systems - galaxies
• in 1929, E. Hubble discovered the law of "red shift" in the spectra of galaxies.
• in 1918, a 2.5-meter reflector was installed at the Mount Wilson Observatory, and in 1947 a 5-meter reflector was put into operation there)
• Radio astronomy emerged in the 1930s with the advent of the first radio telescopes.
• In 1933 Karl Jansky of Bell Labs discovered radio waves coming from the center of the galaxy.
• Grote Reber built the first parabolic radio telescope in 1937.
• In 1948, rocket launches into the high layers of the atmosphere (USA) made it possible to detect X-ray radiation from the solar corona.
• Aronomists began to study the physical nature of celestial bodies and significantly expanded the boundaries of the space under study.
• Astrophysics has become the leading branch of astronomy; it has received especially great development in the 20th century. and continues to grow rapidly today.
• In 1957, the foundation was laid for qualitatively new research methods based on the use of artificial celestial bodies, which subsequently led to the emergence of new branches of astrophysics.
• In 1957, the USSR launched the first artificial Earth satellite, which marked the beginning of the space age for mankind.
• Spacecraft made it possible to bring infrared, X-ray and gamma-ray telescopes out of the earth's atmosphere).
• The first manned space flights (1961, USSR), the first landing of people on the moon (1969, USA) are epoch-making events for all mankind.
• Delivery of lunar soil to Earth (Luna-16, USSR, 1970),
• Landing of descent vehicles on the surface of Venus and Mars,
• Sending automatic interplanetary stations to the more distant planets of the solar system.

(For more details see Timeline of space exploration and Timeline of space exploration.)

1.1.2 Connection of astronomy with other sciences.

Growing out of a once single science of nature - philosophy - astronomy, mathematics and physics have never lost a close connection with each other. Astronomy has played such a leading role in the history of science that many scientists have taken tasks from it and created methods for solving these problems. Astronomy, mathematics and physics have never lost their relationship, which is reflected in the activities of many scientists.

The connection of astronomy with other sciences- Interpenetration and mutual influence of scientific fields:

1.1.3 Structure and scale of the universe

You already know that our Earth with its satellite Moon, other planets and their satellites, comets and minor planets revolve around the Sun, that all these bodies make up solar system. In turn, the Sun and all other stars visible in the sky are part of a huge star system - ours. Galaxy. The closest star to the solar system is so far away that light, which travels at a speed of 300,000 km/s, travels from it to Earth for more than four years. Stars are the most common type of celestial bodies, with hundreds of billions of them in our galaxy alone. The volume occupied by this star system is so large that light can only cross it in 100,000 years.

In Universe There are many other galaxies like ours. It is the location and movement of galaxies that determines the structure and structure of the universe as a whole. The galaxies are so far apart that with the naked eye you can see only the next three: two in the Southern Hemisphere, and from the territory of Russia only one - the Andromeda Nebula. From the most distant galaxies, light reaches the Earth in 10 billion years. A significant part of the matter of stars and galaxies is in such conditions that it is impossible to create in terrestrial laboratories. All outer space is filled with electromagnetic radiation, gravitational and magnetic fields, between stars in galaxies and between galaxies there is a very rarefied substance in the form of gas, dust, individual molecules, atoms and ions, atomic nuclei and elementary particles.

All bodies in the Universe form systems of varying complexity:

1. solar system - The Sun and celestial bodies moving around it (planets, comets, satellites of planets, asteroids), the Sun is a self-luminous body, other bodies, like the Earth, shine with reflected light. The age of the SS is ~5 billion years. There are a huge number of such star systems with planets and other bodies in the Universe.
2. Stars visible in the sky , including Milky Way is a tiny fraction of the stars that make up galaxies (or call our galaxy the Milky Way) - systems of stars, their clusters and the interstellar medium. There are many such galaxies, the light from the nearest ones travels to us for millions of years. The age of the Galaxies is 10-15 billion years.
3. galaxies unite in a kind of clusters (systems)

All bodies are in constant motion, change, development. Planets, stars, galaxies have their own history, often counted in billions of years.

As you know, the distance to the closest celestial body to the Earth - the Moon is approximately 400,000 km. The most distant objects are located from us at a distance that exceeds the distance to the moon by more than 10 times.

Let's try to imagine the sizes of celestial bodies and the distances between them in the Universe, using a well-known model - the school globe of the Earth, which is 50 million times smaller than our planet. In this case, we must depict the Moon as a ball with a diameter of 7 cm, located at a distance of about 7.5 m from the globe. The model of the Sun will have a diameter of 28 m and be at a distance of 3 km, and the model of Pluto - the most distant planet in the solar system - will be removed from us for 120 km. The nearest star to us at this scale of the model will be located at a distance of about 800,000 km, i.e., 2 times farther than the Moon. Our galaxy will shrink to about the size of the solar system, but the most distant stars will still be outside it.

The diagram shows the system and distances:

1 astronomical unit = 149.6 million km(mean distance from the Earth to the Sun).

1pc (parsec) = 206265 AU = 3, 26 St. years

1 light year(St. year) is the distance that a beam of light travels at a speed of almost 300,000 km / s in 1 year. 1 light year is equal to 9.46 million million kilometers!

1.1.4 Features of astronomy and its methods

For thousands of years, astronomers have studied the position of celestial objects in the starry sky and their mutual movement over time. That is why, for a long time, or rather from the III century BC, dominated geocentric system of the world order of Claudius Ptolemy. Recall that according to it, the planet Earth was at the center of the entire universe, and all other celestial bodies, including the Sun, revolved around it.

And only in the middle of the 16th century, or rather in 1543, did the great work of Nicolaus Copernicus “On the Revolution of the Celestial Spheres” come out, in which he argued that the center of our system is not the Earth, but the Sun. That's how it came about heliocentric doctrine, which gave the key to the knowledge of the universe.

Astronomical observations serve as the main method of studying celestial objects and phenomena.

Astronomical observations are purposeful and active registration of information about the processes and phenomena occurring in the Universe.

Astronomy studies the structure of the Universe, movement, physical nature, origin and evolution of celestial bodies and the systems formed by them. Astronomy also explores the fundamental properties of the universe around us. Huge spatio-temporal scales of the studied objects and phenomena determine distinctive features of astronomy.

Information about what is happening outside the Earth in outer space, scientists receive mainly on the basis of the light and other types of radiation coming from these objects. Observations are the main source of information in astronomy. This first feature astronomy distinguishes it from other natural sciences (for example, physics or chemistry), where experiments play a significant role. Opportunities for experiments outside the Earth appeared only thanks to astronautics. But even in these cases, we are talking about conducting experimental studies on a small scale, such as, for example, studying the chemical composition of lunar or Martian rocks. It is difficult to imagine experiments on a planet as a whole, a star or a galaxy.

Second feature due to the significant duration of a number of phenomena studied in astronomy (from hundreds to millions and billions of years). Therefore, it is impossible to directly observe the changes taking place. Even the changes that occur on the Sun are recorded on Earth only after 8 minutes and 19 seconds (this is how long it takes for light to travel the distance from the Sun to the Earth). As for distant galaxies, here we are already talking about billions of years. That is, by studying distant star systems, we are studying their past. When the changes are especially slow, one has to observe many related objects, such as stars. Basic information about the evolution of stars is obtained in this way.

Third feature astronomy is due to the need to indicate the position of celestial bodies in space (their coordinates) and the inability to distinguish which of them is closer and which is farther from us. At first glance, all the observed luminaries seem equally distant to us. It seems to us, as to people in antiquity, that all the stars are equally distant from us and are located on a certain spherical surface of the sky - the celestial sphere - which, as a whole, revolves around the Earth.

So, as a science, astronomy is based primarily on observations. Unlike physicists, astronomers are deprived of the opportunity to experiment. Almost all information about celestial bodies is brought to us by electromagnetic radiation. Only in the last forty years have individual worlds been studied directly: to probe the atmospheres of planets, to study the lunar and Martian soil, to study directly the atmosphere of Titan.

In the 19th century, physical research methods penetrated into astronomy, and a symbiotic science arose - astrophysics, which studies the physical properties of cosmic bodies. Astrophysics divided into: a) practical astrophysics, which develops and applies practical methods of astrophysical research and related tools and instruments that can obtain the most complete and objective information about cosmic bodies; b) theoretical astrophysics, in which, on the basis of the laws of physics, explanations are given for the observed physical phenomena.

Modern astronomy – fundamental physical and mathematical science, the development of which is directly related to scientific and technological progress (STP). To study and explain processes, the entire modern arsenal of various, newly emerged branches of mathematics and physics is used. There is also astronomer's profession. Astronomers in our country are trained in the physics or physics and mathematics faculties of Moscow, St. Petersburg, Kazan, Yekaterinburg and some other universities. About 100 specialists are trained per year. About 2,000 astronomers worked on the territory of the former USSR (now in Russia there are about 1,000, and about 100 are actively working), and there are about 10,000 professional astronomers in the world. A real astronomer is a person of broad outlook. To work as an astronomer, one must know physics, chemistry, biology, not to mention the obligatory mathematics. Russian scientists made the most important fundamental discoveries in astronomy. Georgy Gamow predicted the expansion of the universe. Alexander Friedman created the theory of a non-stationary universe, although Einstein argued that it was stationary. Zel'dovich foresaw accretion, that is, the fallout of matter into black holes. Shklovsky predicted the radio lines of neutral hydrogen. Synchrotron radiation was described by Ginzburg. But the experimental verification of these theoretical works was carried out by the Americans, for which they received Nobel Prizes. We have never had such equipment, such telescopes as in the USA.

The main habitats of astronomers:

• State Institute. P.K. Sternberg (GAISH MSU)
• Space Research Institute
• Institute of Astronomy and Physical Institute of the Russian Academy of Sciences
• Main (Pulkovo) Astronomical Observatory
• Special Astrophysical Observatory of the Russian Academy of Sciences (Northern Caucasus)

The main sections of astronomy:

1.1.5 Telescopes

For research to be accurate, special tools and devices are needed.

one). It is established that Thales of Miletus in 595 BC first used gnomon(an ancient astronomical instrument, a vertical object (an obelisk rod, a column, a pole), which makes it possible to determine the angular height of the Sun by the shortest length of its shadow (at noon). This made it possible to use this instrument as a sundial, and to determine the stages of the solstice, equinox, the length of the year , latitude of the observer and much more.

2). Hipparchus (180-125 AD, Ancient Greece) used an astrolabe, which allowed him to measure the parallax of the Moon, in 129 BC, set the length of the year at 365.25 days, determine the procession and compile in 130 BC. star catalog for 1008 stars, etc.

At various times, there were also an astronomical staff and an astrolabon (this is the first type of theodolite), a quadrant and many other devices and instruments. Observations of celestial bodies and objects are carried out in special institutions - observatories, which arose at the very beginning of the development of astronomy BC. e.

Astronomical observatories were created for possible research and observations in different countries. In our country, there are about two dozen of them: the Main Pulkovo Astronomical Observatory of the Russian Academy of Sciences (GAO RAS), the State Astronomical Institute. P.K. Sternberg (GAISh), Caucasian Mountain Observatory (KGO SAISH), etc.

Real astronomical research began when, in 1609, they invented telescope.

A revolution in astronomy occurred in 1608, after Dutch spectacle maker John Lippershey discovered that two lenses placed in a straight line could magnify objects. Thus the spotting scope was invented.

This idea was immediately taken advantage of by Galileo. In 1609, he built his first 3x telescope and pointed it into the sky. So the telescope turned into a telescope.

The telescope has become the main instrument used in astronomy to observe celestial bodies, receive and analyze the radiation coming from them. . This word comes from two Greek words: tele - far and skopeo - I look.

Telescope - an optical instrument that increases the angle of view at which celestial bodies are visible ( resolution), and collects many times more light than the observer's eye ( penetrating power).

The telescope is used, firstly, in order to collect as much light as possible coming from the object under study, and secondly, to provide an opportunity to study its small details that are inaccessible to the naked eye. The fainter objects the telescope makes it possible to see, the more penetrating power. The ability to distinguish fine details characterizes resolution telescope. Both of these characteristics of a telescope depend on the diameter of its objective.

The amount of light collected by the lens increases in proportion to its area (square of diameter). The pupil diameter of the human eye, even in complete darkness, does not exceed 8 mm. The lens of a telescope can exceed the diameter of the pupil of the eye by tens and hundreds of times. This allows the telescope to detect stars and other objects that are 100 million times fainter than objects visible to the naked eye.

How the telescope works:

Parallel rays of light (for example, from a star) fall on the lens. The lens builds an image in the focal plane. Rays of light parallel to the main optical axis are collected at a focus F lying on this axis. Other beams of light are collected near the focus - above or below. This image is viewed by an observer using an eyepiece.

As you know, if the object is farther than twice the focal length, it gives a reduced, inverted and real image of it. This image is located between the focus and dual focus points of the lens. The distances to the Moon, planets, and even more stars are so great that the rays coming from them can be considered parallel. Consequently, the image of the object will be located in the focal plane.

The diameters of the input and output beams are very different (the input has the diameter of the objective, and the output has the diameter of the image of the objective built by the eyepiece). In a properly adjusted telescope, all the light collected by the lens enters the observer's pupil. In this case, the gain is proportional to the square of the ratio of the lens and pupil diameters. For large telescopes, this value is tens of thousands of times. This is how one of the main tasks of the telescope is solved - to collect more light from the observed objects. If we are talking about a photographic telescope - an astrograph, then the illumination of the photographic plate increases in it.

Main characteristics of telescopes.

1) Telescope aperture(D)- is the diameter of the main mirror of the telescope or its converging lens.

The more aperture, the more light the lens will collect and the fainter objects you will see.

2) F focal length of the telescope - This is the distance at which a mirror or objective lens constructs an image of an infinitely distant object.

Usually this refers to the focal length of the lens (F), since the eyepieces are interchangeable, and each of them has its own focal length.

From focal length depends not only on the magnification, but also on the quality of the image. The more focal length, the better the image quality. The length of a telescope, especially Newton's reflectors and refractors, also depends on the focal length of the telescope.

3) Magnification (or magnification) of the telescope(W) shows how many times the telescope can magnify an object orthe angle at which an observer sees an object. It is equal to the ratio of the focal lengths of the objective F and the eyepiece f.

The telescope increases the visible angular dimensions of the Sun, the Moon, the planets and details on them, but the stars, due to their colossal distance, are still visible through the telescope as luminous dots.

F you most often cannot change, but having eyepieces with different f, you can change magnification or magnification of the telescope D. Having interchangeable eyepieces, it is possible to obtain different magnifications with the same lens. That's why the capabilities of a telescope in astronomy are usually characterized not by the increase, but by the diameter of its lens. In astronomy, as a rule, magnifications of less than 500 times are used. The use of large magnifications is hindered by the Earth's atmosphere. The movement of air, imperceptible to the naked eye (or at low magnifications), leads to the fact that small details of the image become blurry, blurred. Astronomical observatories, which use large telescopes with a mirror diameter of 2–3 m, try to locate in areas with a good astroclimate: a large number of clear days and nights, with high atmospheric transparency.

4) Resolution – minimum angle between two stars seen separately. Simply put, resolution can be understood as the "clarity" of an image.

Resolution can be calculated using the formula:

where δ is the angular resolution in seconds, D

The distance between objects in the sky in astronomy is measured corner, which is formed by rays drawn from the point at which the observer is located to objects. This distance is called corner, and expressed in degrees and fractions of a degree:

degrees - 5 o, minutes - 13 "seconds - 21"

The human eye, without special instruments, distinguishes 2 stars separately from each other if their angular distance is at least 1-2. shares.

The angle at which we see the diameter of the Sun and the Moon ~ 0.5 o = 30".

The limitation on the maximum magnification is imposed by the phenomenon of diffraction - the bending of light waves around the edges of the lens. Due to diffraction, instead of the image of a point, rings are obtained. The angular size of the central spot ( theoretical angular resolution):

where δ is the angular resolution in seconds, λ - radiation wavelength , D is the lens diameter in millimeters.

The smaller the size of the image of a luminous point (star) that a telescope lens gives, the better its resolution. If the distance between the images of two stars is less than the size of the image itself, then they merge into one. The minimum size of a star image (in arcseconds) can be calculated using the formula:

Where λ is the wavelength of light, a D is the lens diameter. A school telescope with a 60 mm objective lens would have a theoretical resolution of about 2 Ѕ . Recall that this exceeds the resolution of the naked eye (2") by 60 times. The actual resolution of the telescope will be less, since the quality of the image is significantly affected by the state of the atmosphere, air movement.

For visible wavelengths at λ = 550 nm on a telescope with a diameter D= 1 m, the theoretical angular resolution will be δ = 0.1". In practice, the angular resolution of large telescopes is limited by atmospheric tremor. In photographic observations, the resolution is always limited by the Earth's atmosphere and guiding errors and cannot be better than 0.3". When observing with the eye, due to the fact that one can try to catch the moment when the atmosphere is relatively calm (a few seconds are enough), the resolution of telescopes with a diameter D, large 2 m, may be close to theoretical. A telescope is considered good if it collects more than 50% of the radiation in a 0.5" circle.

Ways to increase the resolution of the telescope:

1) increasing the diameter of the telescope

2) decrease in the wavelength of the studied radiation

5) Penetrating power telescopea characterized by the limiting magnitude m of the faintest star that can be seen with this instrument under the best observing conditions. For such conditions, the penetrating force can be determined by the formula:

m= 2.1 + 5 lg D

where D is the lens diameter in millimeters, m is the limiting magnitude.

6) Relative hole – diameter ratioDto focal length F:

Telescopes for visual observations typically have aperture ratios of 1/10 or less. For modern telescopes, it is 1/4 or more.

7) Often, instead of a relative hole, the concept is used luminosity equal to ( D/F) 2 . Aperture characterizes the illumination created by the lens in the focal plane.

8) Relative focal length of the telescope(denoted by the inverted letter A) is the reciprocal of the relative hole:

In photography, this quantity is often called diaphragm .

Relative aperture and relative focal length are important characteristics of a telescope objective. These are the opposite of each other. The larger the relative aperture, the smaller the relative focal length and the greater the illumination in the focal plane of the telescope lens, which is beneficial for photography (allows you to reduce shutter speed while maintaining exposure). But at the same time, a smaller image scale is obtained on the photodetector frame.

Let's build the image of the Moon, which gives the lens with focal length F(Fig. 1.6). It can be seen from the figure that the lens does not change the angular dimensions of the observed object - the angle α. Let us now use one more lens - eyepiece 2, placing it from the image of the Moon (point F1) at a distance equal to the focal length of this lens - f, exactly F2. The focal length of the eyepiece must be less than the focal length of the objective. Having built the image that the eyepiece gives, we will make sure that it increases the angular dimensions of the Moon: the angle β is noticeably larger than the angle α.

Types of telescopes:

1. Optical telescopes
   1. Refractor.
   2. Reflector.
   3. Mirror lens.

If a lens is used as the objective of a telescope, then it is called refractor(from the Latin word refracto - I refract), and if a concave mirror, then reflector(reflecto - I reflect). Mirror-lens telescopes use a combination of a mirror and lenses.

Telescope - refractor uses light refraction. The rays that come from the heavenly bodies are collected by a lens or lens system.

The main part of the protozoan refractor – lens - a biconvex lens mounted in front of the telescope. The lens collects radiation. The larger the lens D, the more radiation the telescope collects, the weaker sources can be detected by it. To avoid chromatic aberration, lenses are made composite. However, in cases where it is required to minimize scattering in the system, a single lens must also be used. The distance from the lens to the main focus is called main focal length F.

Telescope - reflector uses light reflection. They use a concave mirror capable of focusing reflected rays.

main element reflector is a mirror - a reflective surface of a spherical, parabolic or hyperbolic shape. It is usually made from a round piece of glass or quartz and then coated with a reflective coating (a thin layer of silver or aluminum). The manufacturing accuracy of the mirror surface, i.e. the maximum allowable deviations from a given shape depends on the wavelength of light at which the mirror will operate. Accuracy should be better than λ/8. For example, a mirror operating in visible light (wavelength λ = 0.5 microns) must be manufactured with an accuracy of 0.06 microns (0.00006 mm).

The optical system facing the observer's eye is called eyepiece . In the simplest case, the eyepiece can consist of only one positive lens (in this case, we will get an image highly distorted by chromatic aberration).

In addition to refractors and reflectors, various types are currently in use. mirror-lens telescopes.

School telescopes are mostly refractors, usually with a biconvex converging lens as their objective.

In the current observatories we can see large optical telescopes. The largest reflecting telescope in Russia, which has a mirror with a diameter of 6 m, was designed and built by the Leningrad Optical and Mechanical Association. It is called the "Large Azimuth Telescope" (abbreviated as BTA).

Its huge concave mirror, which has a mass of about 40 tons, is ground to within fractions of a micrometer. The focal length of the mirror is 24 m. The mass of the entire telescope installation is more than 850 tons, and the height is 42 m. The telescope is controlled by a computer, which allows you to accurately point the telescope at the object under study and keep it in the field of view for a long time, smoothly turning the telescope following the rotation of the Earth . The telescope is part of the Special Astrophysical Observatory of the Russian Academy of Sciences and is installed in the North Caucasus (near the village of Zelenchukskaya in the Karachay-Cherkess Republic) at an altitude of 2100 m above sea level.

At present, it has become possible to use in ground-based telescopes not monolithic mirrors, but mirrors consisting of separate fragments. Two telescopes have already been built and are operating, each of which has a lens diameter 10 m, consisting of 36 separate hexagonal mirrors. By controlling these mirrors with a computer, you can always arrange them so that they all collect light from the observed object in a single focus. It is planned to create a telescope with a composite mirror with a diameter of 32 m, operating on the same principle.

Telescopes are very different - optical (general astrophysical purpose, coronographs, telescopes for observing satellites), radio telescopes, infrared, neutrino, x-ray. For all their diversity, all telescopes that receive electromagnetic radiation decide two main tasks:

• create the sharpest possible image and, in case of visual observations, increase the angular distances between objects (stars, galaxies, etc.);
• collect as much radiation energy as possible, increase the illumination of the image of objects.

Modern telescopes are often used to photograph the image that a lens gives. This is how those photographs of the Sun, galaxies and other objects that you will see on the pages of the textbook, in popular books and magazines, and on sites on the Internet were obtained. Telescopes adapted for photographing celestial objects are called astrographs. Photographic observations have a number of advantages over visual ones. The main benefits include:

1. documentation - the ability to record the occurring phenomena and processes, and for a long time to save the information received;
2. immediacy - the ability to register short-term phenomena occurring at the moment;
3. panorama - the ability to capture several objects on a photographic plate at the same time and their relative position;
4. integrality - the ability to accumulate light from weak sources; the detail of the resulting image.

With the help of telescopes, not only visual and photographic observations are made, but mainly high-frequency photoelectric and spectral observations. Information about the temperature, chemical composition, magnetic fields of celestial bodies, as well as their movement is obtained from spectral observations. In addition to light, celestial bodies emit electromagnetic waves that are longer than light (infrared, radio waves) or shorter than light (UV, X-rays, and gamma rays).

The study of the Universe began and continues for several millennia, but until the middle of the last century, research was exclusively in optical range electromagnetic waves. Therefore, the available radiation region was the range from 400 to 700 nm. The first astronomical scientific observations were astrometric, only the location of the planets, stars and their apparent movement in the celestial sphere were studied.

But celestial bodies give different radiation: visible light, infrared, ultraviolet, radio waves, x-rays, gamma radiation. In the 20th century, astronomy became all-wave. Astronomy is called all-wave, since observations of objects are carried out not only in the optical range. Currently, radiation from space objects is recorded in the entire range of the electromagnetic spectrum from long-wave radio emission (frequency 10 7 , wavelength l = 30 m) to gamma radiation (frequency 10 27 Hz, wavelength l = 3∙10 –19 ×m = 3∙10 –10 nm). For this purpose, various devices are used, each of which is capable of receiving radiation in a certain range of electromagnetic waves: infrared, ultraviolet, x-ray, gamma and radio radiation.

To receive and analyze optical and other types of radiation in modern astronomy, the entire arsenal of achievements in physics and technology is used - photomultipliers, electron-optical converters, etc. At present, the most sensitive light receivers are charge-coupled devices (CCDs), which allow recording individual light quanta . They are a complex system of semiconductors (semiconductor arrays) that use an internal photoelectric effect. In this and other cases, the data obtained can be reproduced on a computer display or presented for processing and analysis in digital form.

Observations in other spectral ranges made it possible to make important discoveries. First invented radio telescopes. Radio emission from space reaches the Earth's surface without significant absorption. To receive it, the largest astronomical instruments, radio telescopes, were built.

Their metal antenna mirrors, which reach a diameter of several tens of meters, reflect radio waves and collect them like an optical reflecting telescope. To register radio emission, special sensitive radio receivers are used. Any radio telescope it is similar to optical in principle of operation: it collects radiation and focuses it on a detector tuned to a selected wavelength, and then converts this signal, showing a conventionally colored image of the sky or object.

So, radio waves brought information about the presence of large molecules in cold molecular clouds, about active galaxies, about the structure of the nuclei of galaxies, including our Galaxy, while optical radiation from the center of the Galaxy is completely delayed by cosmic dust.

To significantly improve the angular resolution, radio astronomy uses radio interferometers. The simplest radio interferometer consists of two radio telescopes separated by a distance called interferometer base. Radio telescopes located in different countries and even on different continents can also be connected into a single observing system. Such systems are called ultra-long baseline radio interferometers(RSDB). Such systems provide the highest possible angular resolution, several thousand times better than any optical telescope.

Our Earth is reliably protected by the atmosphere from penetrating hard electromagnetic radiation, from infrared radiation. Since the atmosphere prevents the penetration of rays to the earth c λ< λ света (ультрафиолетовые, рентгеновские, γ - излучения), то последнее время на орбиту Земли выводятся телескопы и целые орбитальные обсерватории: (т.е развиваются внеатмосферные наблюдения). Т.е. современные инфракрасные, рентгеновские и гамма обсерватории вынесены за пределы земной атмосферы.

Instruments for studying other types of radiation are also usually called telescopes, although in their design they sometimes differ significantly from optical telescopes. As a rule, they are installed on artificial satellites, orbital stations and other spacecraft, since these radiations practically do not penetrate through the earth's atmosphere. She disperses and absorbs them.

Even optical telescopes in orbit have certain advantages over those on the ground. Most big of them space telescope. Hubble created in the USA with mirror diameter 2.4 m objects are available that are 10–15 times fainter than the same telescope on Earth. Its resolution is 0.1S, which is unattainable even for larger ground-based telescopes. Images of nebulae and other distant objects show fine details that are indistinguishable when observed from Earth.

1.1.6 Let's consider telescopes by their types in more detail.

1) Refractor(refracto - I refract) - the refraction of light in the lens is used (refractive).

The first telescope was a refractor telescope with a single lens as an objective. "Spotting scope" made in Holland [H. Lippershey]. According to a rough description, Galileo Galilei made it in 1609 and first sent it to the sky in November 1609, and in January 1610 discovered 4 satellites of Jupiter.

Nowadays, refractors with a single lens are used, perhaps, only in coronographs and some spectral instruments. All modern refractors are equipped with achromatic objectives. The largest refractor in the world is the telescope of the Yerk Observatory (USA) with a 1m lens. Manufactured by Alvan Clark (US Optician). Its lens is 102 cm (40 inches) and was installed in 1897 at the Yerk Observatory (near Chicago). It was built at the end of the last century, and since then, professionals have not built giant refractors. Clark made another 30 inch refractor, which was installed in 1885 at the Pulkovo Observatory and destroyed during the Second World War.

40-inch refractor telescope at the Yerkes Observatory. Snapshot 2006 (Wikipedia)

b) Reflector(reflecto - reflect) - a concave mirror is used to focus the rays.

Newton reflector.

In 1667, the first mirror telescope was invented by I. Newton (1643-1727, England) with a mirror diameter of 2.5 cm at 41 x magnification. Here, a flat diagonal mirror located near the focus deflects the beam of light outside the tube, where the image is viewed through the eyepiece or photographed. The main mirror is parabolic, but if the relative aperture is not too large, it can be spherical. In those days, mirrors were made from metal alloys and quickly dimmed.

The largest telescope in the world W. Keka installed in 1996 a mirror diameter of 10 m (the first of two, but the mirror is not monolithic, but consists of 36 hexagonal mirrors) at the Maun Kea Observatory (California, USA).

Keck Observatory

Segmented primary mirror of the Keck II telescope

In 1995, the first of four telescopes (mirror diameter 8m) was commissioned (ESO Observatory, Chile).

Prior to this, the largest was in the USSR, the mirror diameter was 6m, installed in the Stavropol Territory (Mount Pastukhov, h = 2070m) at the Special Astrophysical Observatory of the USSR Academy of Sciences (monolithic mirror 42t, 600t telescope, you can see stars 24 m). The Special Astrophysical Observatory of the USSR Academy of Sciences was founded in 1966, 6 years after the decision of the Government to establish the country's largest observatory for fundamental space research. The observatory was created as a center for collective use to ensure the operation of the optical telescope BTA (Large Azimuthal Telescope) with a mirror diameter of 6 meters and the RATAN-600 radio telescope with a ring antenna diameter of 600 meters, then the world's largest astronomical instruments. They were put into operation in 1975-1977 and are designed to study objects of near and far space using ground-based astronomy methods.

BTA tower

c) Mirror-lens.(Schmidt chamber) - a combination of both types.

Schmidt-Cassegrain telescope. Large aperture, free from coma (coma aberration) and with a large field of view.

The first one was built in 1930. B.V. Schmidt (1879-1935, Estonia) with a lens diameter of 44 cm Estonian optician, employee of the Hamburg Observatory Barnhard Schmidt installed a diaphragm in the center of the curvature of a spherical mirror, immediately eliminating both coma (comatic aberration) and astigmatism. To eliminate spherical aberration, he placed a specially shaped lens in the diaphragm. The result is a photographic camera with the only aberration - the curvature of the field and amazing qualities: the larger the aperture of the camera, the better the images it gives, and the larger the field of view!

In 1946 James Baker installed a convex secondary mirror in the Schmidt chamber and got a flat field. Somewhat later, this system was modified and became one of the most advanced systems: Schmidt-Cassegrain, which on a field with a diameter of 2 degrees gives a diffractive image quality.

Schmidt-Cassegrain telescope

In 1941 D.D. Maksutov(USSR) made a meniscus telescope, which is advantageous with a short tube. Used by amateur astronomers.

Telescope Maksutov-Cassegrain.

In 1941 D. D. Maksutov found that the spherical aberration of a spherical mirror can be compensated for by a meniscus of high curvature. Having found a good distance between the meniscus and the mirror, Maksutov managed to get rid of coma and astigmatism. The curvature of the field, as in the Schmidt camera, can be eliminated by installing a plano-convex lens near the focal plane - the so-called Piazzi-Smith lens. Having aluminized the central part of the meniscus, Maksutov obtained meniscus analogues of the Cassegrain and Gregory telescopes. Meniscus analogues of almost all telescopes of interest to astronomers have been proposed.

Telescope Maksutov - Cassegrain with a diameter of 150 mm

In 1995, for an optical interferometer, the first telescope with an 8-m mirror (out of 4) with a base of 100m was put into operation (ATACAMA desert, Chile; ESO).

In 1996, the first telescope with a diameter of 10 m (out of two with a base of 85 m) named after. W. Keka introduced at the Maun Kea Observatory (California, Hawaii, USA)

2. - Benefits: in any weather and time of day, you can observe objects that are inaccessible to optical ones. They represent a bowl (like a locator).

Radio astronomy developed after the war. The largest radio telescopes now are the fixed RATAN-600, Russia (commissioned in 1967, 40 km from the optical telescope, consists of 895 individual mirrors 2.1x7.4m in size and has a closed ring with a diameter of 588m), Arecibo (Puerto Rico, 305m- concrete bowl of an extinct volcano, introduced in 1963). Of the mobile ones, they have two radio telescopes with a 100 m bowl.

Of particular importance in our space age is given to orbital observatories. The most famous of them is space telescope. Hubble- launched in April 1990 and has a diameter of 2.4 m. After installing the corrective block in 1993, the telescope registers objects up to the 30th magnitude, and its angular magnification is better than 0.1 "(at this angle a pea is visible from a distance several tens of kilometers).

Schematic diagram of the telescope. Hubble

l. Fixing the material.

1. What astronomical information did you study in courses of other subjects? (natural science, physics, history, etc.)
2. What have you learned?
3. What is astronomy? Features of astronomy, etc.
4. What is the specificity of astronomy compared to other natural sciences?
5. What types of celestial bodies do you know?
6. What are the objects of knowledge in astronomy?
7. What methods and tools of knowledge in astronomy do you know?
8. The purpose of the telescope and its types
9. What is the importance of astronomy in the national economy today?

Values ​​in the national economy:

• - Orientation by stars to determine the sides of the horizon
• - Navigation (navigation, aviation, astronautics) - the art of navigating the stars
• - Exploration of the universe to understand the past and predict the future
• - Astronautics:
• - Exploration of the Earth in order to preserve its unique nature
• - Obtaining materials that are impossible to obtain in terrestrial conditions
• - Weather forecast and natural disaster prediction
• - Rescue of ships in distress
• - Exploration of other planets to predict the development of the Earth

1. View the Observer's Calendar, an example of an astronomical journal (electronic, such as the Sky).
2. On the Internet, go to, find lectures on astronomy, see Astrotop astrolinks, portal: Astronomy in Wikipedia, - using which you can get information on the issue of interest or find it.