The moon, when we see it high above the horizon, seems to us very small: its apparent dimensions are usually compared with objects that are 25-30 cm in diameter. When we see the Moon close to the horizon, it appears to be much larger. It is often thought that in this case the Moon is closer to us, but this is completely wrong: it has been established by measurements that the Moon both at the horizon and high above the golovei has the same apparent dimensions.
When the Moon is low on the horizon, we involuntarily exaggerate its apparent size by comparing the Moon's disk with objects that are visible in the same direction as the Moon (houses, trees, etc.). Owing to their remoteness, these objects also have very small apparent dimensions; we unconsciously compare the apparent dimensions of the moon with the true dimensions of terrestrial objects.
The determination of the apparent dimensions of the Moon in the sky by comparison with terrestrial objects is carried out different people differently. But here are more accurate objective data on this score: we can approximately compare the apparent dimensions of the Moon with the apparent dimensions of a bronze penny placed at a distance of one meter from us.
It seems absolutely incredible. But that this is so, it is not difficult for everyone to verify. Try to measure the apparent diameter of the moon yourself using a small strip of paper.
Let's try to make a small cutout on the edge of this strip more precisely, into which the entire visible diameter of the Moon would fit, from edge to edge. Having done this, we measure the cutout: its size will be approximately equal to the diameter of a bronze penny.
One can imagine the apparent dimensions of the Moon in the sky by doing another experiment. Take a mirror on a moonlit night, stand with your back to the moon and see how big the moon is reflected in it. You will see a small bright spot, about half a centimeter in size. But, of course, the true size of the moon is very far from its apparent size: the moon is very far from us and therefore only seems small.
Knowing the actual distance to the Moon and being able to accurately measure its apparent diameter (diameter), it is possible to calculate its true diameter. It turns out that the actual diameter of the Moon (the greatest distance from the edge to the edge) is 3476 km. This is approximately equal to the distance from Moscow to Tomsk.
As you know, the equatorial diameter the globe is equal to 12,757 km. This means that the Moon is four times smaller than the Earth in its diameter. More precisely, the diameter of the Moon is equal to 0.272 of the diameter of the Earth (7).
But the Moon is a ball, just like the Earth. It is calculated that the circumference of this ball is 10,920 km; it is, therefore, less than the equatorial circumference of the Earth, equal to 40,077 km, approximately four times. And the surface of the Moon is 37,965,499 square meters. km, that is, it is less than the surface of the globe, which is 510,000,000 square meters. km, almost 14 times.
The surface of the Moon in terms of area can be compared with the space occupied on the Earth by Northern and South America together. Our vast homeland covers an area that exceeds half of the entire surface of the moon.
Enjoying now famous formula geometry to determine the volume of the ball, it is easy to calculate the volume of the moon in cubic kilometers. Here is how this volume is expressed: 2,210,200,000 cubic meters. km.
Meanwhile, the volume of the globe is determined by a number of 1083,000,000,000 cubic meters. km. Consequently, in terms of volume, the Moon is 50 times smaller than the Earth; more precisely: the volume of the moon is 0.0202 of the globe.
It is quite remarkable, however, that the Moon has a relatively even smaller mass than the Earth.
We remind readers that the mass of any body characterizes the amount of matter contained in it for a given volume. The more matter in a given body, the more it weighs; consequently, the more effort must be applied to, say, to lift or move a given body.
Careful observations of the motion of the Moon and accurate calculations allow us to conclude that the Moon is almost 82 times lighter than the Earth. And in terms of volume, as we already know, the Moon is smaller than the Earth, about fifty times. This means that the Moon also has a lower density than the Earth (only 0.6 of the density of the Earth). However, we will talk about the density of the Moon later.
These are the main figures characterizing the size of the moon. We see that the Moon is far from being as small as it was thought of before, as it was depicted in fairy tales and religious legends, and as it appears to the eye.
Three articles devoted to our natural satellite were published at once. During its lifetime, the Moon has been bombarded by two different populations of asteroids or comets, and its surface is geologically more complex than previously thought. In addition, after processing data from the Lunar Reconnaissance Orbiter (LRO), scientists compiled a topographic map of our satellite, which marked 5,185 craters with a diameter of more than 20 km.
The first paper describes the results obtained using the LOLA (Lunar Orbiter Laser Altimeter) laser altimeter, designed to compile a three-dimensional map of the Moon's surface with high resolution and installed on the Lunar Reconnaissance Orbiter (LRO).
Previous maps of the Moon were not as detailed: viewing angles and lighting conditions created certain difficulties in consistently determining the size and depth of lunar craters. Thanks to the LOLA altimeter, scientists were able to calculate the height of lunar craters with unprecedented accuracy. The instrument sends laser pulses to the lunar surface, measuring the time it takes for the pulse to bounce off and back. The accuracy of the measurement is simply amazing: the device determines the height of the terrain with an accuracy of 10 cm. Thanks to this, scientists have compiled an unprecedentedly detailed topographic map of our satellite.
“By examining the resulting map, it is possible to determine which craters formed earlier, and which later, on the surface of the Moon that had already been changed before. After analyzing the distribution of craters by size, we came to the conclusion that all meteorites and comets that collided with the Moon can be conditionally divided into two groups: the first, earlier bombardment of our satellite, significantly exceeded the second in terms of percentage large bodies. The moment of transition from one group to another roughly corresponds to the formation of the East Sea (the lunar sea at the western edge of the visible disk of the satellite), which is estimated to be 3.8 billion years old, ”explains study author James Head of Brown University.
Any large meteorite can radically change the history of the planet. Astronomers find on the surfaces of planets such as, for example, Mercury, Mars and even Venus, traces of ancient craters hundreds and thousands of kilometers across. The moon is the most convenient object of study, as it is next to us and preserves evidence of cosmic bombardment, which on Earth has long been erased due to displacement tectonic plates, water and wind erosion. “The moon is like the Rosetta stone for understanding the history of the bombardment of the Earth,” says Head. “Having dealt with the surface of the Moon, we can give an explanation for the fuzzy footprints that we found on our planet.”
In two other studies, scientists describe data obtained from the DLRE (The Diviner Lunar Radiometer Experiment) radiometer, which is also installed on the LRO. This device registers the thermal radiation of the lunar surface, which makes it possible to estimate the composition of lunar rocks. According to the authors of the study, the surface of the moon can be represented in the form of anorthositic highlands, which are rich in calcium and aluminum, as well as basalt seas, where the concentration of elements such as iron and magnesium is increased. Both of these crustal rocks are considered primary, that is, they are formed directly as a result of the crystallization of the mantle substance. On the whole, the DLRE observations confirm the legitimacy of this division: most regions of the lunar surface can be assigned to one of the indicated types.
However, the data from the probe forced scientists to recognize that some lunar hills are very different from others. For example, the DLRE quite often recorded an elevated sodium content, which is not typical for the "ordinary" anorthositic crust. Of greatest interest was the discovery in several areas of minerals rich in silicon oxide, which correspond to evolved rocks, different from primitive anorthosite. Here, an increased content of thorium was previously determined, which is another evidence of the “evolution” of rocks.
As the scientists note in their report, DLRE was unable to register traces of “pure” mantle matter, which, as some studies have shown, should come to the surface in some places. Even while exploring the pool South Pole Aitken - the largest, oldest and deepest impact crater - scientists have not found any evidence of the presence of material from the mantle. Perhaps there really are no outcrops of mantle material on the Moon. Or maybe their area is too small for the DLRE to detect them.
11 WORK 2 PHYSICAL NATURE OF THE MOON Purpose of the work: Studying the topography of the Moon and determining the sizes of lunar objects. Benefits: Photograph of the lunar surface, schematic maps of the visible reverse hemispheres of the Moon, lists of lunar objects (tables 3 and 4 in the Appendix). The Moon is a natural satellite of the Earth. Its surface is covered with mountains, cirques and craters, long mountain ranges. It has wide depressions and is indented with deep cracks. Dark spots on the surface of the moon (lowlands) were called "seas". Most of the moon's surface is occupied by "continents" - lighter hills. The hemisphere of the Moon visible from the earth is very well studied. The reverse hemisphere of the Moon is not fundamentally different from the visible one, but it has fewer “sea” depressions and small bright flat areas called galassoids have been found. About 200,000 features have been registered on the lunar surface, of which 4,800 are catalogued. The relief of the Moon was formed in a complex process of evolution with the participation of internal and external forces. The study of the lunar surface is carried out from photographs and maps compiled on their basis. At the same time, it should be remembered that photographs and maps reproduce a telescopic image of the Moon, in which its North Pole is below. Determination of the linear dimensions of lunar formations. Let d1 be linear diameter Moon, expressed in kilometers; d2 is the angular diameter of the Moon, expressed in minutes; D is the linear diameter of the photographic image of the Moon in millimeters. Then the scales of the photographic image will be: linear scale: l = d1/D, (1) angular scale: ρ = d2/D. (2) The apparent angular diameter of the Moon varies with its parallax, and its values for each day of the year are given in astronomical yearbooks. However, approximately one can take d2 = 32'. Knowing the distance to the Moon (r = 380,000 km) and its angular diameter, we can calculate the linear diameter d1 = r ⋅ d2. By measuring in millimeters the size d of a lunar object in a photograph with known scales, we obtain its angular dρ and linear d1 12 dimensions: dρ = ρ ⋅ d, (3) d1 = l ⋅ d. (4) From the known scales l and ρ of the photograph of the full moon, it is possible to determine the scales l1 and ρ1 of the photograph of a section of the lunar surface. To do this, it is necessary to identify identical objects and measure the dimensions d and d' of their images in photographs in millimeters. On the scale of a photograph of a section of the lunar surface: dρ = ρ1 ⋅ d’, (5) d1 = l1 ⋅ d. (6) Using formulas (3) and (4), we have: l1 = l ⋅ d/d’, (7) ρ1 = ρ ⋅ d/d’. (8) Using the obtained scales ρ1 and l1, it is possible to determine the angular and linear dimensions of lunar objects with sufficient accuracy. Progress. 1. Set the names of lunar objects that appear under the numbers indicated by the teacher. 2. Calculate the angular and linear scales of the photographic map of the visible hemisphere of the Moon and determine the angular and linear dimensions of the sea, the extent mountain range and diameters of two craters (on the instructions of the teacher). 3. Using a photograph of a section of the lunar surface, identify the objects of the lunar surface, by the size of which calculate the scale of this photograph. Submit a report on the work in a self-developed form. Test questions. 1. What observations of the Moon prove that there is a change of day and night? 2. How many revolutions around its axis does the Moon make in relation to the Sun during the year? 3. Is it possible to observe lunar auroras while on the Moon? 4. Why is the Moon facing the Earth on one side, but is observed in different phases? 5. Why can more than 50% of the Moon's surface be observed from Earth? 13 WORK 3 STAR SYSTEMS Purpose of work: Acquaintance with some methods of studying galaxies. Benefits: Photographic Standards various types galaxies, photos of galaxies. One of the simplest and, therefore, the most widely used classifications of galaxies currently in existence is the Hubble classification. Galaxies in this classification are divided into irregular (I), elliptical (E) and spiral (S). Each class of galaxies contains several subclasses or types. Comparing photographs of the studied galaxies with photographs of their characteristic representatives, according to which the classification was created, the types of these galaxies are determined. If the distance D to the galaxy or the distance modulus (m−M) is known, where m is the apparent magnitude and M is the absolute magnitude of the object, then its linear dimensions can be calculated from the measured angular dimensions p: l = D ⋅ Sin(p). (1) Since the apparent sizes of galaxies are very small, then, expressing p in arc minutes and considering that 1 radian = 3438', we get: l = D ⋅ p/3438'. (2) The absolute magnitude of the object is M = m + 5 – 5lgD. (3) However, the distance D, calculated by the modulus of the distance, will be overestimated if the absorption of light in space is not taken into account. To do this, in formula (3) it is necessary to take into account the corrected value of the apparent stellar magnitude: m' = m - γCE, (4) where γ is the coefficient, which for visual rays (when using mv) is 3.7, and for photographic rays (when using ) is equal to 4.7. CE \u003d C - C0. (5) C = mpg - mv is the apparent color index, and C0 is the true color index, determined by spectral class object (Table 2 in the Appendix). 14 Then, logD = 0.2(m' – M) + 1. (6) The distance to a galaxy can be determined from the redshift of the lines in its spectrum: D = V/H, (7) where H = 100km/s Mpc is the Hubble constant ; V = с ⋅ ∆λ/λ; c = 300,000 km/s is the speed of light; ∆λ = λ' - λ; λ'- wavelength of shifted lines; λ is the normal wavelength of the same lines. Progress. 1. Determine the names of the constellations in which the star systems are located. 2. Using the scale of the photo star system specified by the teacher, determine its angular dimensions. 3. Calculate the linear dimensions and distance to the same star system from the angular dimensions and the distance modulus. 4. According to the Hubble classification, classify the star systems indicated in Table 11*. 5. Present the results of measurements and calculations in the form of tables and draw conclusions. Test questions. 1. Hubble's law. 2. What is redshift? 3. Main characteristics of galaxies. 4. What is our Galaxy? 15 Table 11. No. Number of stars. Equatorial visible stars. Spectrum Modulus of coordinate system value Sp dist. NGC M α δ mv mpg mv-Mpg h m m 1 4486 87 12 28 .3 +12°40' 9 .2 10m.7 G5 +33m.2 2 5055 63 13h13m.5 +42°17' 9m.5 10m.5 F8 +30m.0 3 5005 − 13h08m.5 +37°19' 9m.8 11m.3 G0 +32m.9 4 4826 64 12h54m.3 +21°47' 8m.0 8m.9 G7 +26m.9 5 3031 81 9h51m.5 +69°18' 7m.9 8m.9 G3 +28m.2 6 5194 51 13h27m.8 +47°27' 8m.1 8m.9 F8 +28m.4 7 5236 83 13h34m.3 - 29°37' 7m.6 8m.0 F0 +28m.2 8 4565 − 12h33m.9 +26°16' 10m.2 10m.7 G0 +30m.3 * NGC – “New General Catalog of Nebulae and Star Clusters”, compiled by Dreyer and published in 1888; M - "Catalogue of Nebulae and Star Clusters", compiled by Messier and published in 1771. REFERENCES 1. Vorontsov-Velyaminov B.A. Astronomy: for the 11th grade of high school. - M.: Education, 1989. 2. Bakulin P.I., Kononov E.V., Moroz V.I. General astronomy course. - M.: Nauka, 1983. 3. Mikhailov A.A. Atlas of the starry sky. - M.: Nauka, 1979. 4. Galkin I.N., Shvarev V.V. The structure of the moon. - M.: Knowledge, 1977. 5. Vorontsov-Velyaminov B.A. extragalactic astronomy. - M .: Nauka, 1978. Compiled by: Raskhozhev Vladimir Nilovich Leonova Liana Yurievna Editor Kuznetsova Z.E. 16 APPENDIX Table 1. Information about bright stars Name in Spectrum. Temperature Distance Apparent stellar Name Color of a star in the constellation class 103 K Holy year ps magnitude Aldebaran α Taurus K5 3.5 Orange 64 20 1m.06 Altair α Orla A6 8.4 Yellowish 16 4.9 0m.89 Antares α Scorpio M1 5.1 Red 270 83 1m.22 Arcturus α Bootes K0 4.1 Orange 37 11.4 0m.24 Betelgeuse α Orion M0 3.1 Red 640 200 0m.92 Vega α Lyrae A1 10.6 White 27 8.3 0m.14 Deneb α Cygnus A2 9.8 White 800 250 1m.33 Capella Yellow 52 Voznichego 16 0m,21 Castor α Gemini A1 10.4 White 47 14.5 1m,58 Pollux β Gemini 4.2 Orange 33 10.7 1m,21 Procyon α Canis Minor F4 6.9 Yellowish 11.2 3.4 0m,48 Regulus α Leo B8 13.2 Rigel 1,3β 24 White 80 Oriona B8 12.8 Blue 540 170 0m,34 Sirius α Big Dog A2 16.8 White 8.7 2.7 -1m.58 Spike α Virgo B2 16.8 Blue 300 90 1m.25 Fomalhaut α Southern Pisces A3 9.8 White 23 7.1 1m.29 Table 2. True color index Spectrum. O5 B0 B5 A0 A5 F0 F5 G0 G5 K0 K5 M0 M5 class True value -0m.50 -0m.45 -0m.39 -0m.15 0m.00 +0m.12 +0m. 64 +0m,89 +1m,20 +1m,30 +1m,80 colors, C0 17 Table 3. List of lunar sea names Russian name International name Oceanus of Storms Oceanus Procellarum Bay Central Sinus Medium Bay of Heat (Unrest) Sinus Aestuum Sea of Fertility (Abundance) Mare Foecunditatis Sea of Nectar Mare Nectaris Sea of Tranquility Mare Tranquillitatis Sea of Crises (Dangers) Mare Crisium Sea of Clarity Mare Serenitatis Sea of Cold Mare Frigoris Bay of Dew Sinus Roris Sea of Rains Mare Imbrium Rainbow Bay Sinus Iridum Sea of Vapors Mare Vaporum Sea of Clouds Mare Nubium Sea of Humidity Mare Humorum Sea of Smith Mare Smythii Sea of Margins Mare Margins South Sea Mare Australe Sea of Moscow Mare Mosquae Sea of Dreams Mare Ingenii Sea of Oriental Mare Orientalis Table 4. Ordered list lunar circuses and craters. Русская Международная № Русская Международная № транскрипция транскрипция транскрипция транскрипция 1 Ньютон Newton 100 Лангрен Langrenus 13 Клавдий Clavius 109 Альбатегний Albategnius 14 Шейнер Scheiner 110 Альфонс Alphonsus 18 Неарх Nearchus 111 Птолемей Ptolemaeus 22 Магин Maginus 119 Гиппарх Hipparchus 29 Вильгельм Wilhelm 141 Гевелий Hevelius 30 Тихо Tycho 142 Риччиоли Riccioli 32 Штефлер Stoefler 146 Кеплер Kepler 33 Мавролик Maurolycus 147 Коперник Copernicus 48 Вальтер Walter 168 Эратосфен Eratosthenes 52 Фурнерий Furnerius 175 Геродот Herodotes 53 Стевин Stevinus 176 Аристарх Aristarchus 69 Виета Vieta 186 Посидоний Posidonius 73 Пурбах Purbach 189 Автолик Autolycus 74 Лакайль La-Caile 190 Aristillus Aristillus 77 Sacrobosco Sacrabosco 191 Archimedes Archimedes 78 Fracastor Fracastor 192 Timocharis Timocharis 80 Petavius Petavius 193 Lambert Lambert 84 Arzachel Arzachel 201 Gauss Gauss 86 Bullialdus Bullialdus 208 Eudoxus Eudoxus 88 Cavendish Cavendish 8 Aristote 209 Mersenius 210 Plato Plato 90 Gassendi Gassendi 220 Pythagoras Pythagoras 95 Catharina Catharina 228 Atlas Atlas 96 Cyril Cyrillus 229 Hercules Hercules
> > > Dimensions of the Moon
What is the size of the moon- Earth satellite. Description of mass, density and gravity, real and apparent size, supermoon, illusion of the Moon and comparison with the Earth in the photo.
The Moon is the brightest object in the sky (after the Sun). To a terrestrial observer, it seems gigantic, but this is only because it is located closer than other objects. In size, it occupies 27% of the earth (ratio 1: 4). If compared with other satellites, then ours is in 5th place in terms of size.
The average lunar radius is 1737.5 km. The value doubled will be the diameter (3475 km). The equatorial circle is 10917 km.
The area of the Moon is 38 million km 2 (this is less than any total area of the continent).
Mass, density and gravity
- Mass - 7.35 x 10 22 kg (1.2% of the earth). That is, the Earth exceeds the lunar mass by 81 times.
- Density - 3.34 g / cm 3 (60% of the earth). According to this criterion, our satellite ranks second, losing to Saturn's moon Io (3.53 g/cm3).
- The force of attraction grows only up to 17% of the earth, so 100 kg there will turn into 7.6 kg. That is why astronauts can jump so high on the lunar surface.
Supermoon
The moon wraps around the Earth not in a circle, but in an ellipse, so sometimes it is much closer. The closest distance is called perigee. When this moment coincides with the full moon, we get a super moon (14% larger and 30% brighter than usual). It repeats every 414 days.
horizon illusion
There is an optical effect that makes the apparent size of the moon appear even larger. This happens when it rises behind distant objects on the horizon. This trick is called the moon illusion or the Ponzo illusion. And although it has been observed for many centuries, there is no exact explanation yet. In the photo you can compare the size of the Moon and the Earth, as well as the Sun with Jupiter.
One of the theories suggests that we are accustomed to watching the clouds at a height and understand that on the horizon they are miles away from us. If the clouds on the horizon reach the same size as those overhead, then, despite the distance, we remember that they must be huge. But since the satellite appears at the same size as overhead, the brain automatically aims to zoom in.
Not everyone agrees with this formulation, so there is another hypothesis. The moon appears close to the horizon because we can't compare its size to trees and other terrestrial objects. Without comparison, it seems larger.
To check for an illusion of the moon, you need to put your thumb on the satellite and compare the size. When she returns to height again, then repeat this method again. It will be the same size as before. Now you know how big the moon is.
Brief information
The Moon is the Earth's natural satellite and the brightest object in the night sky. The force of gravity on the Moon is 6 times less than on Earth. The difference between day and night temperatures is 300°C. The rotation of the Moon around its axis occurs at a constant angular velocity in the same direction in which it revolves around the Earth, and with the same period of 27.3 days. That is why we see only one hemisphere of the Moon, and the other, called the far side of the Moon, is always hidden from our eyes.Moon phases. The numbers are the age of the moon in days. Details on the moon depending on the equipment Due to its proximity, the Moon is a favorite object for astronomy lovers, and deservedly so. Even the naked eye is enough to get a lot of pleasant impressions from contemplating our natural satellite. For example, the so-called "ash light" that you see when observing the thin crescent of the Moon is best seen in the early evening (at dusk) on a waxing or early morning on a waning Moon. Also, without an optical instrument, interesting observations can be made of the general outlines of the Moon - seas and land, the ray system surrounding the Copernicus crater, etc. By pointing binoculars or a small low-power telescope at the Moon, you can study the lunar seas, the largest craters and mountain ranges in more detail. Such an optical device, not too powerful at first glance, will allow you to get acquainted with all the most interesting sights of our neighbor. As the aperture grows, the number of visible details also increases, which means that there is an additional interest in studying the Moon. Telescopes with a lens diameter of 200 - 300 mm make it possible to examine fine details in the structure of large craters, to see the structure of mountain ranges, to examine many furrows and folds, and to see unique chains of small lunar craters. Table 1. Capabilities of various telescopes
|
Lens diameter (mm) |
Magnification (x) |
permissive |
The diameter of the smallest formations, |
| 50 | 30 - 100 | 2,4 | 4,8 |
| 60 | 40 - 120 | 2 | 4 |
| 70 | 50 - 140 | 1,7 | 3,4 |
| 80 | 60 - 160 | 1,5 | 3 |
| 90 | 70 - 180 | 1,3 | 2,6 |
| 100 | 80 - 200 | 1,2 | 2,4 |
| 120 | 80 - 240 | 1 | 2 |
| 150 | 80 - 300 | 0,8 | 1,6 |
| 180 | 80 - 300 | 0,7 | 1,4 |
| 200 | 80 - 400 | 0,6 | 1,2 |
| 250 | 80 - 400 | 0,5 | 1 |
| 300 | 80 - 400 | 0,4 | 0,8 |
Of course, the above data is primarily the theoretical limit of the capabilities of various telescopes. In practice, it is often somewhat lower. The culprit for this is mainly the restless atmosphere. As a rule, on the vast majority of nights, the maximum resolution of even a large telescope does not exceed 1"". Be that as it may, sometimes the atmosphere "settles down" for a second or two and allows observers to squeeze the maximum possible out of their telescope. For example, on the most transparent and calm nights, a telescope with a lens diameter of 200 mm is able to show craters with a diameter of 1.8 km, and a 300 mm lens - 1.2 km. Necessary equipment The Moon is a very bright object that, when viewed through a telescope, often simply dazzles the observer. To reduce brightness and make observations more comfortable, many amateur astronomers use an ND filter or a variable density polarizing filter. The latter is more preferable, as it allows you to change the level of light transmission from 1 to 40% (Orion filter). Why is it convenient? The fact is that the amount of light coming from the moon depends on its phase and the magnification applied. Therefore, when using a conventional ND filter, you will occasionally encounter a situation where the image of the moon is either too bright or too dark. The variable density filter is free from these disadvantages and allows you to set a comfortable brightness level if necessary.
Orion Variable Density Filter. Demonstration of the possibility of selecting the filter density depending on the phase of the moon
Unlike the planets, observations of the Moon usually do not use color filters. However, the use of a red filter often helps to highlight areas of the surface with a lot of basalt, making them darker. The red filter also helps to improve the image in unstable atmospheres and attenuate moonlight. If you are serious about exploring the moon, you need to get a lunar map or atlas. On sale you can find the following cards of the moon: "", as well as a very good "". There are also free editions, however, on English language- " " and " ". And of course, be sure to download and install "Virtual Atlas of the Moon" - a powerful and functional program that allows you to get all the necessary information to prepare for lunar observations.What and how to observe on the moon
When is the best time to see the moon?
At first glance it seems absurd, but the full moon is not the most best time to observe the moon. The contrast of lunar features is minimal, making it almost impossible to observe them. During the "lunar month" (the period from new moon to new moon), there are two most favorable periods for observing the moon. The first begins shortly after the new moon and ends two days after the first quarter. This period is preferred by many observers, since the visibility of the Moon falls on the evening hours.
The second favorable period begins two days before the last quarter and lasts almost until the new moon. These days, the shadows on the surface of our neighbor are especially long, which is clearly visible on the mountainous terrain. Another plus of observing the Moon in the phase of the last quarter is that in the morning the atmosphere is calmer and cleaner. Due to this, the image is more stable and clear, which makes it possible to observe finer details on its surface.
Another important point is the height of the moon above the horizon. The higher the Moon, the less dense layer of air overcomes the light coming from it. Therefore, there is less distortion and better image quality. However, the height of the moon above the horizon varies from season to season.
table 2. The most and least favorable seasons for observing the moon in various phases
When planning your observations, be sure to open your favorite planetarium program and determine the hours of the best visibility.
The moon moves around the earth in an elliptical orbit. The average distance between the centers of the Earth and the Moon is 384,402 km, but the actual distance varies from 356,410 to 406,720 km, due to which the apparent size of the Moon varies from 33" 30"" (at perigee) to 29" 22"" (apogee). ).
Of course, you should not wait until the distance between the Moon and the Earth is minimal, just note that at perigee one can attempt to consider those details of the lunar surface that are at the limit of visibility.
Starting observations, point your telescope to any point near the line that divides the moon into two parts - light and dark. This line is called the terminator, being the boundary of day and night. During the growing moon, the terminator indicates the place of sunrise, and during the waning - sunset.
When observing the Moon in the terminator region, you can see the tops of the mountains, which are already illuminated by the sun's rays, while the lower part of the surface surrounding them is still in shadow. The scenery along the terminator line changes in real time, so if you spend a few hours at the telescope observing this or that lunar landmark, your patience will be rewarded with an absolutely stunning sight.
What to see on the moon
craters- the most common formations on the lunar surface. They got their name from Greek word denoting "cup". Most of the lunar craters are of impact origin, i.e. formed as a result of impact cosmic body on the surface of our satellite.
Moon Seas- dark areas that stand out clearly on the lunar surface. At its core, the seas are lowlands that occupy 40% of the entire surface area visible from the Earth.
Look at the moon on a full moon. The dark spots that form the so-called "face on the moon" are nothing more than lunar seas.
Furrows- lunar valleys, reaching a length of hundreds of kilometers. Quite often, the width of the furrows reaches 3.5 km, and the depth is 0.5–1 km.
Folded veins- in appearance they resemble ropes and, apparently, are the result of deformation and compression caused by the sinking of the seas.
mountain ranges- lunar mountains, the height of which ranges from several hundred to several thousand meters.
Domes- one of the most mysterious formations, since their true nature is still unknown. At the moment, only a few dozen domes are known, which are small (usually 15 km in diameter) and low (several hundred meters), round and smooth elevations.
How to observe the moon
As mentioned above, observations of the Moon should be carried out along the terminator line. It is here that the contrast of lunar details is maximum, and thanks to the play of shadows, unique landscapes of the lunar surface open up.
When looking at the Moon, experiment with magnification and find the most appropriate for the given conditions and for this object.
In most cases, three eyepieces will suffice for you:
1) An eyepiece that gives a small increase, or the so-called search one, which allows you to comfortably view the full disk of the moon. This eyepiece can be used for general sightseeing, for observation lunar eclipses, as well as conduct lunar excursions with it for family members and friends.
2) An eyepiece of medium power (about 80-150x, depending on the telescope) is used for most observations. It will also be useful in unstable atmospheres where high magnification is not possible.
3) A powerful eyepiece (2D-3D, where D is the diameter of the lens in mm) is used to study the lunar surface in detail at the limit of the telescope's capabilities. Requires good atmospheric conditions and complete thermal stabilization of the telescope.
Your observations will become more productive if they are focused. For example, you can start your study with the list " ", compiled by Charles Wood. Also pay attention to the series of articles "" that talk about lunar sights.
Another fun activity can be looking for tiny craters visible at the limit of your equipment.
Make it a habit to keep an observation diary in which you regularly record the conditions of observation, the time, the phase of the moon, the state of the atmosphere, the magnification used, and a description of the objects you see. Such records can be accompanied by sketches.
10 most interesting lunar objects
(Sinus Iridum) T (moon age in days) - 9, 23, 24, 25 
It is located in the northwestern part of the moon. Viewable with 10x binoculars. In a telescope at medium magnification is an unforgettable sight. This ancient 260 km diameter crater has no rim. Numerous small craters dot the remarkably flat bottom of Rainbow Bay.
(Copernicus) T - 9, 21, 22 
One of the most famous lunar formations is visible with a small telescope. The complex includes the so-called system of rays, extending for 800 km from the crater. The crater is 93 km in diameter and 3.75 km deep, making sunrises and sunsets over the crater a breathtaking sight.
(Rupes Recta) T - 8, 21, 22 
A tectonic fault 120 km long, easily visible in a 60 mm telescope. A straight wall runs along the bottom of a ruined ancient crater, traces of which can be found on the east side of the fault.
(Rümker Hills) T - 12, 26, 27, 28 
A large volcanic dome visible with a 60mm telescope or large astronomical binoculars. The hill has a diameter of 70 km and a maximum height of 1.1 km.
(Apennines) T - 7, 21, 22 
The mountain range is 604 km long. Easily visible with binoculars, but its detailed study requires a telescope. Some peaks of the ridge rise above the surrounding surface for 5 or more kilometers. In some places, the mountain range is crossed by furrows.
(Plato) T - 8, 21, 22 
Visible even with binoculars, the Plato crater is a favorite among astronomers. Its diameter is 104 km. The Polish astronomer Jan Hevelius (1611-1687) named this crater "Great Black Lake". Indeed, through binoculars or a small telescope, Plato looks like a large dark spot on the bright surface of the moon.
Messier and Messier A
(Messier and Messier A) T - 4, 15, 16, 17 
Two small craters that require a telescope with a 100 mm objective lens to observe. Messier has an oblong shape measuring 9 by 11 km. Messier A is slightly larger - 11 by 13 km. To the west of the craters Messier and Messier A, two bright beams 60 km long stretch.
(Petavius) T - 2, 15, 16, 17 
Despite the fact that the crater is visible in small binoculars, a truly breathtaking picture opens up in a telescope with a high magnification. The domed bottom of the crater is dotted with furrows and cracks.
(Tycho) T - 9, 21, 22 
One of the most famous lunar formations, famous mainly due to the giant system of rays surrounding the crater and extending for 1450 km. The rays are perfectly visible through small binoculars.
(Gassendi) T - 10, 23, 24, 25 
The oval crater, elongated for 110 km, is accessible for observation with 10x binoculars. The telescope clearly shows that the bottom of the crater is dotted with numerous crevices, hills, and there are also several central hills. A careful observer will notice that the walls near the crater have been destroyed in some places. At the northern end is the small crater Gassendi A, which, together with its older brother, resembles a diamond ring.
