A lunar eclipse occurs when the Moon (in the full moon phase) enters the cone of the shadow cast by the Earth. The diameter of the spot of the Earth's shadow at a distance of 363,000 km (the minimum distance of the Moon from the Earth) is about 2.5 times the diameter of the Moon, so the entire Moon can be obscured. A lunar eclipse can be observed on half of the Earth's territory (where the Moon is above the horizon at the time of the eclipse). The view of the shadowed Moon from any vantage point is the same. The maximum theoretically possible duration of the total phase of a lunar eclipse is 108 minutes; such were, for example, the lunar eclipses of August 13, 1859, July 16, 2000.

At each moment of the eclipse, the degree of coverage of the Moon's disk by the Earth's shadow is expressed by the phase of the eclipse F. The phase value is determined by the distance 0 from the center of the Moon to the center of the shadow. In astronomical calendars, the values ​​\u200b\u200bof and 0 are given for different moments of the eclipse.

If the Moon falls into the total shadow of the Earth only partially, there is partial eclipse. With it, part of the Moon is dark, and part, even in the maximum phase, remains in partial shade and is illuminated by the sun's rays.

Around the cone of the Earth's shadow there is a penumbra - a region of space in which the Earth obscures the Sun only partially. If the Moon passes through the penumbra, but does not enter the shadow, penumbral eclipse. With it, the brightness of the Moon decreases, but only slightly: such a decrease is almost imperceptible to the naked eye and is recorded only by instruments. Only when the Moon in a penumbral eclipse passes near the cone of total shadow, in a clear sky, one can notice a slight darkening from one edge of the lunar disk.

An eclipsed moon flickers in the sky above the Monument to the Savior of the World in San Salvador, El Salvador, December 21, 2010.

(Jose CABEZAS/AFP/Getty Images)

During a total eclipse, the Moon takes on a reddish or brownish hue. The color of the eclipse depends on the state of the earth's upper atmosphere, since only the light that has passed through it illuminates the Moon during a total eclipse. If you compare pictures of total lunar eclipses from different years, it's easy to see the difference in color. For example, the eclipse of July 6, 1982 was reddish, while the eclipse of January 20, 2000 was brown. The Moon acquires such colors during eclipses due to the fact that the earth's atmosphere scatters more red rays, so you can never observe, say, a blue or green lunar eclipse. But total eclipses differ not only in color, but also in brightness. Yes, exactly, brightness, and there is a special scale for determining the brightness of a total eclipse, called the Danjon scale (in honor of the French astronomer André Danjon, 1890-1967).

The gradation of the Danjon scale has 5 points. 0 - the eclipse is very dark (the Moon is barely visible in the sky), 1 - the eclipse is dark gray (details are noticeable on the Moon), 2 - the eclipse is gray with a brown tint, 3 - the light red-brown eclipse, 4 - the very light copper-red eclipse (The moon is clearly visible, and all the main details of the surface are distinguishable).

If the plane of the lunar orbit lay in the plane of the ecliptic, then lunar (as well as solar) eclipses would occur monthly. But most of the time the Moon spends either above or below the plane of the Earth's orbit due to the fact that the plane of the lunar orbit has a five-degree inclination to the plane of the Earth's orbit. As a result, the natural satellite of the Earth falls into its shadow only twice a year, that is, at the time when the nodes of the lunar orbit (the points of its intersection with the ecliptic plane) are on the Sun-Earth line. Then a solar eclipse occurs on a new moon, and a lunar eclipse on a full moon.

Every year there are at least two lunar eclipses, however, due to the mismatch of the planes of the lunar and earth orbits, their phases differ. Eclipses repeat in the same order every 6585⅓ days (or 18 years 11 days and ~8 hours - a period called saros); knowing where and when a total lunar eclipse was observed, one can accurately determine the time of subsequent and previous eclipses that are clearly visible in this area. This cyclicity often helps to accurately date the events described in the historical annals. The history of lunar eclipses goes far into the past. The first total lunar eclipse is recorded in ancient Chinese chronicles. With the help of calculations, it was possible to calculate that it happened on January 29, 1136 BC. e. Three more total lunar eclipses are recorded in the Almagest by Claudius Ptolemy (March 19, 721 BC, March 8 and September 1, 720 BC). In history, lunar eclipses are often described, which is very helpful in establishing the exact date of a particular historical event. For example, the commander of the Athenian army Nikias was frightened by the beginning of a total lunar eclipse, a panic began in the army, which led to the death of the Athenians. Thanks to astronomical calculations, it was possible to establish that this happened on August 27, 413 BC. e.

In the Middle Ages, a total lunar eclipse did Christopher Columbus a great favor. His next expedition to the island of Jamaica was in a difficult situation, food and drinking water were running out, and people were threatened with starvation. Columbus's attempts to get food from the local Indians ended in vain. But Columbus knew that on March 1, 1504, a total lunar eclipse would occur, and in the evening he warned the leaders of the tribes living on the island that he would steal the Moon from them if they did not deliver food and water to the ship. The Indians just laughed and left. But, as soon as the eclipse began, the Indians were seized with indescribable horror. Food and water were immediately delivered, and the leaders on their knees begged Columbus to return the Moon to them. Columbus, of course, could not "refuse" this request, and soon the moon, to the delight of the Indians, shone again in the sky. As you can see, an ordinary astronomical phenomenon can be very useful, and knowledge of astronomy is simply necessary for travelers.

Observations of lunar eclipses can bring some scientific benefit, as they provide material for studying the structure of the earth's shadow and the state of the upper layers of the earth's atmosphere. Amateur observations of partial lunar eclipses come down to accurate recording of the moments of contact, photographing, sketching and describing changes in the brightness of the Moon and lunar objects in the eclipsed part of the Moon. The moments of contact of the lunar disk with the Earth's shadow and the descent from it are fixed (with the greatest possible accuracy) by the clock, adjusted according to the exact time signals. It is also necessary to note the contacts of the earth's shadow with large objects on the moon. Observations can be made with the naked eye, binoculars or a telescope. The accuracy of observations naturally increases when observing through a telescope. To register eclipse contacts, it is necessary to set the telescope to the maximum magnification for it and direct it to the corresponding points of contact of the Moon's disk with the Earth's shadow several minutes before the predicted moment. All entries are recorded in a notebook (an eclipse observation journal).

If an amateur astronomer has at his disposal a photoexposure meter (a device that measures the brightness of an object), then with its help you can plot the change in the brightness of the lunar disk during an eclipse. To do this, you need to set the exposure meter so that its sensitive element is directed exactly at the disk of the moon. The readings of the device are taken every 2-5 minutes, and are recorded in the table in three columns: the brightness measurement number, the time and the brightness of the moon. At the end of the eclipse, using the data in the table, it will be possible to display a graph of the change in the brightness of the Moon during this astronomical phenomenon. As a light meter, you can use any camera that has an automatic exposure system with an exposure scale.

Photographing the phenomenon can be done with any camera that has a removable lens. When shooting an eclipse, the lens is removed from the camera, and the body of the apparatus is attached to the eyepiece part of the telescope using an adapter. It will be shooting with ocular magnification. If the lens of your camera is non-removable, then you can simply attach the device to the eyepiece of the telescope, but the quality of such an image will be worse. If your camera or camcorder has the Zoom function, there is usually no need for additional magnifying tools, because. the dimensions of the moon at the maximum magnification of such a camera are sufficient for filming.

However, the best image quality is obtained when photographing the Moon in the direct focus of the telescope. In such an optical system, the telescope lens automatically becomes a camera lens, only with a longer focal length.

Organization of a network of observation points for surface water bodies

To monitor land waters, the following organizations are organized:

Stationary network of observation points for the natural composition and pollution of surface waters;

Specialized network of points for solving research problems;

Temporary expeditionary network of points.

The organization and conduct of surface water quality observations are based on the following principles: comprehensiveness and systematic nature of observations, consistency of their timing with typical hydrological situations, determination of water quality indicators using common methods. Compliance with these principles is achieved by establishing control programs (for physical, chemical, hydrobiological and hydrological indicators) and the frequency of control, performing water sample analysis according to unified methods or those providing the required accuracy (Vildyaev, 1999).

The network of hydrochemical observations should cover

in space:

If possible, all water bodies located on the territory of the study basin;

The entire length of the watercourse with the determination of the influence of its largest tributaries and the discharge of wastewater into it;

The entire water area of ​​the reservoir with the determination of the impact on it of the largest tributaries and the discharge of wastewater into it;

in time:

All phases of the hydrological regime (spring flood, summer low water, summer and autumn rain floods, freezing, winter low water);

Years of different water content (high-water, medium-water and low-water);

Daily changes in the chemical composition of water;

Catastrophic wastewater discharges into water bodies (Vildyaev, 1999).

Types of surface water quality observations OGSNK

Within the framework of the OGCOS, the following is carried out:

Observations of the level of pollution of surface waters in terms of physical, chemical, hydrological and hydrobiological indicators in sensitive points;

Observations designed to solve special problems.

Each of these types of observations is carried out as a result of:

Preliminary (reconnaissance) observations and studies on water bodies or their sections;

Systematic observations on water bodies at selected points (Vildyaev, 1999).

25. Observation points for surface water pollution, rules for their installation. Categories of observation points for the quality of water bodies.

The main principle of organizing observations of the quality of water bodies is their complexity. It provides for a coherent program of work in hydrology, hydrochemistry and hydrobiology, providing observations of water quality in terms of physical, chemical and hydrobiological indicators. A necessary condition is the synchronism of all observation systems and the consistency of the timing of their implementation. Water quality observations are carried out according to special programs, the choice of which depends on the category of the observation point. The frequency of work on hydrochemical and hydrobiological parameters is also determined by the category of the observation point. The choice of a water quality control program is related to the use of the watercourse or body of water, the chemical composition of the wastewater, and the information that the water user requires. Observation points for water quality of streams and reservoirs are divided into 4 categories. The location of control points is regulated by special rules for monitoring water quality. Items of the first category are installed on medium and large watercourses and reservoirs of great economic importance:

In cities and industrial zones with a population of more than 1 million inhabitants;

In places of wintering and spawning of valuable species of commercial fish;

In places of organized wastewater discharge, where a high degree of water pollution is constantly observed;

In areas where accidental discharges of pollutants are repeated;

In cities with a population of 0.5 to 1 million inhabitants;

On pre-dam sections of rivers important for fisheries;

In places where drainage water is discharged from irrigated areas and industrial waste water;

When rivers cross the state border of the Russian Federation;

In areas with moderate water pollution.

In cities with a population of less than 0.5 million inhabitants;

On the closing sections of large and medium-sized rivers;

In the mouths of polluted tributaries of large rivers and reservoirs;

In places where wastewater is discharged with low water pollution.

In uncontaminated areas of watercourses and reservoirs;

At water bodies located in the territories of national parks and state reserves.

In fact, a solar eclipse is the shadow of the moon that falls on the earth's surface. In diameter, it is about 200 km, that is, many, many times smaller than the diameter of our planet. That is why the phenomenon is observed only in a specific band, along which the lunar shadow passes.

If a person is in the shadow zone, he observes a total solar eclipse when the Moon completely hides the Sun. The sky darkens and stars appear in it. As in the evening, it becomes cooler, and animals and birds become silent, frightened by the sudden darkness. Some plants even fold their leaves.

If observers stay near the band of such an eclipse, they can see a partial solar eclipse. In this case, the Moon does not completely cover the solar disk, but only part of it. The sky is no longer so dark, the stars are not visible. Usually a partial eclipse is observed at a distance of about two thousand km from the zone of a total eclipse.

solar eclipse time

This phenomenon occurs on the new moon. The satellite is not visible, because that side of it, which "looks" at the Earth, is not illuminated by the Sun. Because of this, it seems as if a fireball covers a black spot that has arisen from nowhere.

The shadow cast by the Moon towards our planet looks like a converging cone. Its tip is located a little further than the Earth. And when the shadow falls on the surface of the planet, it is a black spot with a diameter of 150–270 km, and not a point. Following the satellite, this spot moves along the surface of the planet, moving at a speed of one kilometer per second.

Due to its high speed, the shadow cannot cover any place on the globe for a long time. With a total eclipse, the maximum possible duration of darkness is 7.5 minutes. With a partial eclipse - about two hours.

Frequency of solar eclipses

On Earth, from 2 to 5 eclipses occur annually, while only two of them are total or annular. In a hundred years, 237 solar eclipses occur, 160 of them are partial, 63 are total, and 14 are annular. At some points on the earth's surface, solar eclipses in a large phase occur very rarely, and total eclipses are a complete rarity. For example, on the territory of Moscow in the period from the 11th to the 18th centuries. only 159 solar eclipses were observed, of which only 3 were total. This is for 700 years!

Usually total solar eclipses are observed in Western countries, but it is known exactly when the Moon will completely cover the disk in Russia. This will happen only after 13 years in 2026 on August 12, and after this date after another 7 years - in 2033. Recall that the nearest past eclipse took place on August 1, 2008.

You can watch the solar eclipse on video and photo frames on the Internet.

In order for an eclipse to occur, it doesn’t matter if it’s lunar or solar, and the Moon, the Sun, and the Earth must be on the same line. So, during a solar eclipse, the Moon passes between the Earth and the Sun, and it, as it were, hides the Sun from view, closes it. But during a lunar eclipse, the Moon is already covered by the shadow of the Earth, which is cast from the planet illuminated by the Sun.

There are total, partial and penumbral lunar eclipses. With a total lunar eclipse, the Moon is completely “closed” by the earth’s shadow, with a partial one, the Moon plunges into the shadow only by half, while the maximum possible dimming is half the moon’s disk. During a penumbral eclipse, the Moon only passes through the Earth's penumbra. Lunar eclipses only occur when the moon is full. But the full moon happens every month, however, for some reason, we do not notice such frequent lunar eclipses. What is it connected with? But with this: in order for such a friendly company in the face of the Sun, Moon and Earth to delight us with lunar eclipses every night with the participation of the full Moon, they must “be friends” in a completely different way. And this is what this “friendship” should look like: the Moon should revolve around the Earth in the same plane in which the Earth revolves around the Sun. But this does not happen, because the plane of the lunar orbit is slightly, quite a bit, inclined with respect to the plane of the Earth's revolution around the Sun (in scientific terms, this plane is called the plane of the ecliptic). Thus, it turns out that the eclipse occurs only when the Moon is located near the nodes of its own orbit. The phase length of a lunar eclipse is determined by how close the eclipse is to the lunar node. So, the closer it is to it, the longer the phase will be. Since during an eclipse, the Moon is covered by the shadow of the Earth, then, logically, it should completely disappear from view. However, as we know, this never happens. And all because the earth's atmosphere, quite simply, scatters the rays of the sun, and they, in turn, fall on the moon darkened by the earth's shadow. Most often, the darkened Moon has a reddish color. This is due to the fact that red and orange rays pass best through the atmosphere of our planet.

It was a brief digression into the basics of astronomy and lunar eclipse. But after all, we have not answered how often such a phenomenon as a lunar eclipse happens. More precisely answered, but covered some part of this phenomenon. That is, now we know that a lunar eclipse is possible only with a full moon. But it is still not clear how many times, for example, there are lunar eclipses a year? But even ancient astronomers calculated the frequency of lunar eclipses per year. So, they brought out such a thing as "saros". Saros lasts exactly 18 years, 11 days and 8 hours. And during this time period there are 43 solar and 28 lunar eclipses. Thus, at least two lunar eclipses are possible per year, sometimes the number of eclipses increases by one more, and there are also years without eclipses at all. But this frequency of lunar eclipses is calculated for the entire Earth. And if we consider individual regions of the globe, then their frequency will be different. In certain places, eclipses will be seen more often than in others.

In the end, I would like to note that both lunar and solar eclipses are the most beautiful phenomena that nature has endowed us with. And this is a fairly common occurrence, but it may well seem to us that they happen no more than once a decade, that's when the media tells us about the next major eclipse.

Imagine a clear sunny day, a brightly shining solar disk in the sky, nature lives its usual life. But here, on the right edge of the Sun, a small damage first gradually appears, then it slowly increases, and as a result, until recently, the former round disk takes the form of a sickle. Sunlight gradually weakens, it becomes cooler. The resulting crescent becomes very small, and eventually the last flashes of light disappear behind the black disk. A clear day instantly turns into night, stars appear in the darkened sky, a lemon-orange dawn flashes from all sides, and a black circle shines in place of the Sun, surrounded by an indistinct silvery glow. Frightened by the onset of darkness, animals and birds abruptly fall silent, and almost all plants roll up their leaves. But a few minutes will pass, and the Sun will again reveal its triumphant face to the world and nature will come to life. For thousands of years, the phenomenon of a solar eclipse inspired people with both fear and awe.

Why doesn't the Sun get eclipsed every new moon, and why doesn't the moon happen every full moon through the earth's shadow? If the orbits of the Moon and the Earth lay in the same plane, then during each new moon and full moon, the Moon would be exactly on a straight line connecting the Earth and the Sun, which means that either a solar or lunar eclipse would occur. However, the plane of the Moon's orbit is inclined to the plane of the Earth's orbit at an angle of 5.9 ° and intersects it at two opposite points (the nodes of the lunar orbit), and therefore eclipses occur only when the Moon passes through one of its nodes at the time of a new moon or a full moon, and that's when the sun, earth and moon "line up" in one line. When at such moments the Moon is in a new moon, a solar eclipse occurs, and when in a full moon - a lunar eclipse.

Solar eclipses are by no means visible from all areas of the Earth's daytime hemisphere, since, due to its small size, the Moon cannot hide the Sun from the entire Earth's hemisphere. Its diameter is less than the diameter of the Sun by about 400 times, but at the same time, the Moon is almost 400 times closer to the Earth compared to the Sun, so the apparent sizes of the Moon and the Sun are almost the same, so the Moon, albeit in a very limited area, can cover us from Sun. The nature of the eclipse depends on the distance of the Moon from the Earth, and, since the Moon's orbit is not circular, but elliptical, this distance changes, and depending on this, the apparent size of the Moon also changes slightly. If at the time of a solar eclipse the Moon is closer to the Earth, then the lunar disk, being slightly larger than the sun, will completely cover the Sun, which means that the eclipse will be total. If - further, then its visible disk will be smaller than the solar one and the Moon will not be able to close the entire Sun - a light rim will remain around it. Such an eclipse is called an annular eclipse. Illuminated by the Sun, the Moon casts into space a converging cone of shadow and penumbra surrounding it. When these cones intersect with the Earth, the lunar shadow and penumbra fall on it. A spot of the lunar shadow with a diameter of about 300 km runs along the earth's surface, leaving a trail 10-12 thousand km long, and where it passes, a total solar eclipse occurs, in the area captured by penumbra, a partial eclipse, when only part of the solar disk. It often happens that the lunar shadow passes the Earth, and the penumbra partially captures it, then only partial eclipses occur.

Since the speed of the shadow moving along the Earth's surface, depending on the geographic latitude, ranges from 2000 km/h (near the equator) to 8000 km/h (near the poles), a total solar eclipse observed at one point lasts no more than 7.5 minutes, moreover, the maximum value is reached in very rare cases (the next eclipse of 7 minutes 29 seconds will occur only in 2186). A solar eclipse begins in the western regions of the earth's surface at sunrise and ends in the eastern regions at sunset. The total duration of all phases of a solar eclipse on Earth can reach 6 hours. The degree of coverage of the Sun by the Moon is called the phase of the eclipse. It is defined as the ratio of the closed part of the diameter of the solar disk to its entire diameter. With partial eclipses, the attenuation of sunlight is not noticeable (with the exception of eclipses with a very large phase), and therefore the phases of the eclipse can only be observed through a dark filter.

If total solar eclipses were visible in every locality often enough, one would get used to them as quickly as one would get used to changes in the phases of the moon. But they happen so rarely that not every generation of local residents manages to see them at least once - at one point on the earth's surface, total solar eclipses can be observed only once every 300-400 years. Lunar eclipses, especially total ones, were no less feared than solar ones. After all, this night star sometimes completely disappeared from the vault of heaven, and the darkened part of the moon soon took on a gray color with a reddish sheen, becoming more and more blood-dark. In ancient times, lunar eclipses were attributed a special sinister influence on earthly events. The ancients believed that the moon at this moment is shedding blood, which promises great disasters for mankind. The first lunar eclipse recorded in the ancient Chinese chronicles dates back to 1136 BC.

Solar eclipses: to understand the cause of solar and lunar eclipses, the priests for centuries kept count of total and partial eclipses. First, it was noticed that the lunar ones occur only on the full moon, and the solar ones only on the new moon, then - that solar eclipses do not occur at every new moon and lunar eclipses do not occur at every full moon, and also that solar eclipses did not happen when the moon was visible. Even during a solar eclipse, when the light was completely dimmed, and the stars and planets began to peep through the unnaturally dark twilight, the moon was nowhere to be seen. This aroused curiosity and gave rise to a careful study of the place where the Moon should have been immediately after the end of the solar eclipse. It was soon discovered that on the night following the day of a solar eclipse, the Moon was always in its nascent form very close to the Sun. Having noted the location of the Moon before and immediately after the solar eclipse, it was determined that during the eclipse itself, the Moon really passed from the west to the eastern side of the place occupied by the Sun, and complex calculations showed that the coincidence of the Moon and the Sun in the sky took place precisely at the time when the Sun was eclipsed. The conclusion became obvious: the Sun is obscured from the earth by the dark body of the Moon.

After finding out the causes of the solar eclipse, we moved on to unraveling the mystery of the lunar one. Although in this case it was much more difficult to find a satisfactory explanation, since the light of the moon was not obscured by any opaque body that stood between the night luminary and the observer. Finally, it has been observed that all opaque bodies cast a shadow in the direction opposite to the light source. It has been suggested that, perhaps, the earth, illuminated by the Sun, gives that shadow, reaching even to the Moon. It was necessary to either confirm or disprove this theory. And it was soon proved that lunar eclipses occur only during the full moon. This confirmed the assumption that the cause of the eclipse is the shadow from the earth falling on the Moon - as soon as the earth became between the Moon and the light source - the Sun, the light of the Moon, in turn, became invisible and an eclipse occurred.

Lunar eclipses: during the full phase, the Moon appears copper-red, especially as it passes towards the central region of the shadow. Its color is due to the fact that the sun's rays, tangent to the earth's surface, penetrating its atmosphere, are scattered and enter the Earth's shadow through the air column. This is best done with red and orange rays, and therefore it is they who color the disk of the Moon in crimson, brick or copper colors, depending on the state of the earth's atmosphere. Lunar eclipses occur when the full moon passes near the nodes of its orbit. Depending on whether it is partially or completely immersed in the earth's shadow, both partial and total shadow lunar eclipses occur. Near the lunar nodes, within 17° on either side of them, there are zones of lunar eclipses. The closer to the lunar node an eclipse occurs, the greater its phase, determined by the proportion of the lunar diameter covered by the earth's shadow. The entry of the Moon into the shadow or penumbra of the Earth usually occurs imperceptibly. A total eclipse is preceded by partial phases, and at the moment of the final immersion of the Moon into the earth's shadow, it occurs, lasting about two hours. The frequency of lunar eclipses for any particular place on Earth is higher than the frequency of solar eclipses only because they are visible from the entire night hemisphere of the Earth. In this case, the duration of the total phase of a solar eclipse on the Moon can reach 2.8 hours. Observations of total lunar eclipses make it possible to study the structure and optical properties of the earth's atmosphere, as well as the thermal properties of various parts of the lunar surface, including the change in their temperature during different phases of the eclipse.

Eclipse cycles: as a result of long-term observations, it turned out that both lunar and solar eclipses inevitably repeat in the same order after the expiration of the time interval through which the mutual position of the sun, moon and nodes of the lunar orbit is repeated.

1 - Literally 2-3 minutes before the onset of the total phase of the eclipse, bright points flash - this is light breaking through the valleys and gorges between the lunar mountains.

2 - Solar corona during the eclipse of February 26, 1998. Different colors - a decrease in the brightness of the corona, small spots - streams of gas heated to millions of degrees.

The ancient Greeks called this gap the saros. It is 223 revolutions of the moon, that is, 18 years, 11 days and 8 hours. After the expiration of the saros, all eclipses are repeated, but under somewhat different conditions, since in 8 hours the Earth rotates by 120 °, and therefore the lunar shadow will go along the Earth 120 ° to the west than it was 18 years ago. The ancient Egyptians, Babylonians, Chaldeans and other "cultural" peoples as early as 2500 BC, not knowing the causes of the eclipse, were able to predict their onset with an accuracy of 1-2 days within their limited territory. But since they could not have the results of observations on the entire globe, they used for calculations a triple, or large, saros containing an integer number of days. The sequence of solar and lunar eclipses after the triple Saros is repeated at the same geographic longitude. It is believed that a large saros - namely 19,756 days - was first calculated by ancient Babylonian astronomers priests. The establishment of the saros was one of the greatest discoveries of antiquity, since it led to the discovery of the true cause of eclipses as early as the 6th century BC.

The earliest written evidence of a solar eclipse dates back to October 22, 2137 BC. Moreover, this eclipse was not predicted by court astronomers, and therefore the horror of the unexpectedly coming night was extremely great. However, those ancient astronomers could hardly be accused of negligence, since at that time the prediction of such phenomena in any particular place was not an easy task at all. It is impossible to make an accurate forecast of the eclipse from the saros, it was possible to indicate only the approximate date and area of ​​​​its visibility. It was a difficult task to accurately calculate the time of the eclipse, as well as the conditions for its visibility. And to solve it, astronomers have been studying the motion of the earth and the moon for several centuries. At present, eclipses have been calculated with a high degree of accuracy both for thousands of years ago and for hundreds of years ahead. The study of ancient solar eclipses helps modern scientists correct the dates of many historical events and even change their sequence. After all, each total solar eclipse occurs in a certain and rather narrow strip of the earth's surface, the position of which changes from year to year. And therefore, according to the area where it took place, it is possible, with the help of calculations, to absolutely accurately determine their date. In addition, by comparing the movements of the moon's shadow over the earth's surface, one can establish the natural evolution of the motion of the moon. It was this comparison that first led scientists to think about the secular deceleration of the Earth's rotation, which is 0.0014 seconds per century.

total solar eclipse is a unique opportunity to study the outer layers of the Sun's atmosphere - the chromosphere and corona.

The passage of the moon's shadow across the planet's surface during a solar eclipse. In 1715, Edmund Halley accurately predicted the time and areas of the total solar eclipse on May 3, 1715, and also made a map showing the size of the moon's shadow (295 km).

And although their observations are carried out daily, this is not enough. The corona is only visible during a total solar eclipse, as the brightness of the corona's light is a million times less than that of the disk's light. In addition, light from the Sun's disk is scattered by the Earth's atmosphere and the brightness of this scattered light is close to that of the corona. The brightest part of the Sun, the one that appears yellow to us, is called the photosphere. During a total eclipse, the lunar disk completely covers the photosphere. Only after the photosphere hides behind the Moon can the chromosphere be seen for a short time in the form of a ragged red ring surrounding a black disk.

The solar corona extends far from the Sun - to the orbits of Jupiter and Saturn. During the 11-year cycle of solar activity, both the shape of the corona and its overall brightness change. Extremely interesting were the spectra of the corona taken near the solar disk. Against the background of the continuous spectrum, bright emission lines were visible, which for many years were one of the greatest mysteries of science. It was allowed only in the 40s of the twentieth century. It turned out that these lines emit strongly ionized iron and calcium atoms, the existence of which requires temperatures reaching a million degrees.

So-called eclipsing observations, in particular, radio astronomical ones, played an important role in clarifying the physical conditions existing in the solar corona. To date, one of the main tasks is to study the infrared radiation of interplanetary dust. During eclipses, photometric, colorimetric, spectrophotometric and polarimetric observations are also performed. There is also no doubt that eclipsing observations of the Sun have made an invaluable contribution to scientists' understanding of the Sun and the interstellar medium. In order to fruitfully use the few minutes during which an eclipse occurs, astronomers prepare for it for many months, making accurate calculations of the eclipse band, studying weather reports in the eclipse band, and looking for the best place to observe.