The science
When the full moon arrives, the moon's bright light captures our attention, but the moon also holds other secrets that may surprise you.
1. There are four types of lunar months
Our months correspond approximately to the period of time that it takes for our natural satellite to go through complete phases.
From excavations, scientists discovered that people since the Paleolithic era have been counting days by linking them with the phases of the Moon. But in reality there are four different types lunar months.
1. Anomalistic- the length of time it takes the Moon to orbit the earth, measured from one perigee (the point of the Moon's orbit closest to the Earth) to the other, which takes 27 days, 13 hours, 18 minutes, 37.4 seconds.
2. Nodal- the length of time it takes the Moon to travel from the point where the orbits intersect and return to it, which takes 27 days, 5 hours, 5 minutes, 35.9 seconds.
3. Sidereal- the length of time it takes the Moon to circle the earth, guided by the stars, which takes 27 days, 7 hours, 43 minutes, 11.5 seconds.
4. Synodic- the length of time it takes the Moon to go around the Earth, guided by the Sun (this is the time interval between two serial connections with the Sun - the transition from one new moon to another), which takes 29 days, 12 hours, 44 minutes, 2.7 seconds. The synodic month is used as a basis in many calendars and is used to divide the year.
2. From Earth we see a little more than half of the Moon
Most reference books mention that because the Moon rotates only once during each orbit around the Earth, we never see more than half of its entire surface. In truth, we get to see more during its elliptical orbit, namely 59 percent.
The Moon's rotation speed is the same, but its rotation frequency is not, allowing us to see only the edge of the disk from time to time. In other words, the two movements do not occur in perfect sync, even though they converge towards the end of the month. This effect is called libration by longitude.
Thus, the Moon wobbles in the east and west directions, allowing us to see a little farther in longitude at each edge. We will never see the remaining 41 percent from the Earth, and if someone were on the other side of the Moon, he would never see the Earth.
3. It takes hundreds of thousands of moons to match the brightness of the sun
The Full Moon has an apparent magnitude of -12.7, but the Sun is 14 times brighter, with an apparent magnitude of -26.7. The brightness ratio of the Sun and Moon is 398.110 to 1. It will take so many moons to match the brightness of the sun. But this is all a moot point, since there is no way to fit so many moons in the sky.
The sky is 360 degrees, including the half beyond the horizon that we can't see, so there are more than 41,200 square degrees in the sky. The moon is only half a degree across, giving an area of 0.2 square degrees. So you could fill the entire sky, including the half beneath our feet, with 206,264 full Moons and still have 191,836 left to match the brightness of the Sun.
4. The first and last quarter of the Moon are not half as bright as the Full Moon.
If the surface of the Moon were like a completely smooth billiard ball, then the brightness of its surface would be the same everywhere. In this case, it would be twice as bright.
But The moon has a very uneven terrain, especially near the border of light and shadow. The landscape of the Moon is pierced by countless shadows from mountains, boulders and even the smallest particles of lunar dust. In addition, the surface of the Moon is covered with dark areas. Ultimately, in the first quarter, the Moon 11 times less bright than when full. The Moon is actually slightly brighter in the first quarter than in the last quarter because some parts of the moon reflect light better during this phase than in other phases.
5. 95 percent of the illuminated Moon is half as bright as the full Moon
Believe it or not, about 2.4 days before and after the full moon, the Moon shines half as brightly as the full Moon. Even though 95 percent of the Moon is illuminated at this time and will appear to most normal observers to be full, it is about 0.7 magnitudes less bright than at full, making it half as bright.
6. When viewed from the Moon, the Earth also goes through phases
However, these phases are opposite lunar phases
that we see from Earth. When we see the new moon, we can see the full Earth from the Moon. When the Moon is in the first quarter, then the Earth is in the last quarter, and when the Moon is between the second quarter and the full moon, then the Earth is visible in the form of a crescent, and finally, the Earth in a new phase is visible when we see the full moon.
From any point on the Moon (except for the farthest side, where Earth cannot be seen), the Earth is in the same place in the sky.
From the Moon, the Earth appears four times larger than the full Moon When we observe it, and depending on the state of the atmosphere, it shines from 45 to 100 times brighter than the full Moon. When the full Earth is visible in the lunar sky, it illuminates the surrounding lunar landscape with a bluish-gray light.
7. Eclipses also change when viewed from the Moon.
Not only do the phases change places when viewed from the Moon, but also lunar eclipses are solar eclipses when viewed from the Moon. In this case, the Earth's disk covers the Sun.
If it completely covers the Sun, a narrow strip of light surrounds the dark disk of the Earth, which is illuminated by the Sun. This ring has a reddish tint, as it is due to the combination of light from sunrises and sunsets that occur at this moment. That's why during full lunar eclipse, The moon takes on a reddish or copper hue.
When a total eclipse of the Sun occurs on Earth, an observer on the Moon may see for two or three hours a small, distinct dark spot move slowly across the Earth's surface. This dark shadow of the Moon that falls on Earth is called umbra. But unlike a lunar eclipse, where the Moon is completely engulfed by the Earth's shadow, the lunar shadow is several hundred kilometers smaller when it touches the Earth, appearing only as a dark spot.
8. Craters of the Moon are named according to certain rules
Lunar craters were formed by asteroids and comets that collided with the Moon. It is believed that only on the near side of the Moon approximately 300,000 craters, more than 1 km wide.
Craters named after scientists and explorers. For example, Copernicus Crater was named after Nicolaus Copernicus, a Polish astronomer who, in the 1500s, discovered that the planets move around the sun. Archimedes Crater named after a mathematician Archimedes, who made many mathematical discoveries in the 3rd century BC.
Tradition assign personal names to lunar formations started in 1645 Michael van Langren(Michael van Langren ) , a Brussels engineer who named the main features of the Moon after kings and great men on Earth. On his lunar map he named the largest lunar plain ( Oceanus Procellarum) in honor of its patron Spanish Philip IV.
But just six years later, Giovanni Batista Riccoli( Giovanni Battista Riccioli ) from Bologna created his own lunar map, removing the names he gave van Langren and instead assigned the names of mostly famous astronomers. His map became the basis of a system that survives to this day. In 1939, British Astronomical Association released a catalog of officially named lunar formations. " Who's Who on the Moon", indicating the names of all entities accepted International Astronomical Union(MAS).
To date MAS continues to decide what names to give to craters on the Moon, along with names for all astronomical objects. MAS organizes the naming of each specific celestial body around a specific theme.
The names of craters today can be divided into several groups. As a rule, the craters of the Moon were called in honor of deceased scientists, scientists and researchers, who have already become renowned for their contributions in their respective fields. So craters around the crater Apollo And Seas of Moscow on the Moon will be named after American astronauts and Russian cosmonauts.
9. The Moon has a huge temperature range
If you start searching the Internet for data on the temperature on the Moon, you will most likely get confused. According to the data NASA, temperatures at the Moon's equator range from very low (-173 degrees Celsius at night) to very high (127 degrees Celsius during the day). In some deep craters near the poles of the Moon, the temperature is always around -240 degrees Celsius.
During a lunar eclipse, when the Moon moves toward Earth's shadow in just 90 minutes, surface temperatures can drop by 300 degrees Celsius.
10. The moon has its own time zones
It is quite possible to tell the time on the Moon. In fact, in 1970 the company Helbros Watches(Helbros Watches) asked Kenneth L. Franklin ( Kenneth L. Franklin )
, who for many years was the chief astronomer at New York Hayden Planetarium create watches for astronauts who set foot on the Moon. These clocks measured time in so-called " Lunations" is the time it takes for the Moon to orbit the Earth. Each Lunation corresponds to 29.530589 days on Earth.
For the Moon, Franklin developed a system called lunar time. He imagined local lunar time zones following standard time zones on Earth, but based on meridians that were 12 degrees wide. They will be called simply " 36 degrees Eastern Standard Time" etc., but it is possible that other more memorable names will be adapted, such as " Copernican time", or " time of Western calm".
To get acquainted with the main lunar seas, optical instruments are not required - they are easily distinguished by the naked eye. With binoculars, especially prismatic ones, everything is clearly visible lunar seas, as well as the largest of the craters and mountain ranges. Light rays diverging from the Tycho crater are clearly visible. Other craters, surrounded by a halo of light beams, look like bright light dots through binoculars.
Detailed study of lunar features can be carried out using telescopes with objective lenses of 60 or 80 mm. Other optical instruments such as telescopes (for example, binocular tubes) are also suitable for this purpose.
It should be noted that lunar details are especially clearly visible near the terminator (the boundary of the light and dark parts of the Moon's disk). The worst time to study the lunar relief is the full moon, when the lunar mountains and craters cast almost no shadows. Sometimes it is possible to observe the Moon during the day, but in this case the bright glow of the daytime sky veils many lunar details. Next, we will describe the appearance of the Moon in different phases from new moon to full moon, paying attention only to the most important and most interesting details. The remaining objects can be identified from the map of the Moon and the catalog of lunar details. As a scale to judge the size of lunar formations, you can sculpt the Copernicus crater, whose diameter is 90 km.
You can begin studying lunar topography from the second day after the new moon. At this time, the Moon in the form of a narrow crescent is clearly visible against the background of the evening dawn. Of the lunar seas, one can distinguish the Smith Sea, the Mare Sea, and the Southern Sea near the limb (the edge of the lunar disk). Noteworthy are the huge crater Gauss (diameter 133 km) and the smaller craters Seneca, Plutarch, and Napier. The Kostner crater is interesting with its dark bottom - a feature characteristic of some, mainly large, craters.
On the third day after the new moon, the terminator passes along the surface of the Sea of Crisis, where the coastal ridges and swells covering the surface of the sea are clearly visible. Up close south pole The moon is highlighted by the sunlit Leibniz mountain range, some of whose peaks are higher than Everest (Chomolungmu). Notable craters are Lemopie (where the Soviet Lunokhod 2 operated), Cleomedes with its polygonal shaft, Endymion with a dark bottom and the huge craters Furnerius and Petavius.
On the fourth day, the Sea of Crises is visible in its entirety. This is a typical crater sea, similar in nature to craters with a dark bottom. In the narrow part of the “isthmus” between the Seas of Crisis and Tranquility, a very bright crater Proclus is visible, surrounded by a crown of light rays. On the partially visible surface of the Sea of Plenty, you can try to distinguish the mysterious craters - the Messier twins, subject to not entirely clear changes (their diameter is close to 10 km). Of the large craters, Fabricius and Reith are clearly distinguishable. From the latter, the wide Reita Valley stretches for 350 km - one of the largest tectonic faults on the Moon.
On the fifth day after the new moon, a trio of craters Theophilus, Kirill, Katarina appears, the shafts of which overlap each other, which indicates the different ages of these large formations (Theophilus diameter is 105 km).
The Moon looks very impressive on the sixth day from the new moon. The Terminator passes through the middle of the Sea of Clarity, on the surface of which many large and long swells are visible. Near the terminator, an ancient mountainous region is visible - the lunar Altai, which was once the shore of the now disappeared lunar sea. Many large craters (Hercules, Janssen, Plinii, etc.) are clearly visible, and among the small craters on the surface of the Sea of Clarity, it is worth finding the famous Linnaeus crater (diameter 10 km), which, like the Messier twin craters, is subject to mysterious changes.
A day after the first quarter, three large craters appear - Ptolemy, Alphonse and Arzachel. The first of them has a diameter of 157 km and at certain points its shaft rises above the flat bottom by 2.3 km. The central mountain of Alfonso is an active lunar volcano, as was first proven in 1958 by the observations of N.A. Kozyrev and V.I. Ezersky.
Above the surface of the Sea of the Rains near the Apennines is the site of the hard landing of Luna 2 - the first automatic station, which reached the Moon in 1959. On the northern shore of the Mare Mons, the huge crater Platon (diameter 100 km), the height of which is close to 2 km, attracts attention. At the bottom of Plato, some observers noticed details that varied in shape, color and position, the nature of which still remains unclear.
South of Plato, on the surface of the Sea of Rains, a lonely Mountain Piton is visible, and not far from Plato are Mounts Pico and Tenerife.
When Lupa reaches nine to ten days of age, the Copernicus crater, one of the youngest and best-preserved lunar craters, becomes visible in all its glory. The crown of light rays surrounding it is apparently one of the signs of the youth of the lunar ring mountains. The height of the Copernicus shaft in some bridges reaches 3.7 km. The Eratosthenes crater, which is smaller in size than Copernicus, is equally well preserved. Between these two craters you can see the dilapidated ancient crater of Stages.
In the southern part of the Moon, a vast mountainous country dotted with craters appears to the eye of the observer. Here you can see the Tycho crater, the light rays of which stretch for thousands of kilometers.
On the eleventh or twelfth day after the new moon, the Kepler crater appears - a reduced resemblance to Copernicus, also surrounded by a crown of light rays. In the north, Rainbow Bay looks very impressive - an ancient gigantic crater, half-submerged in the Sea of Rains. The diameter of this former crater is close to 300 km.
The Aristarchus crater is the brightest formation on the Moon (its diameter is 50 km). Next to it is its twin - the Herodotus crater, and to the north of them is the famous broken valley of Schröter. This area on the Moon appears to be the most volcanically active.
Before the full moon, t.s. On the 13th-14th day after the new moon, huge craters O. Struve, Riccioli, Grimaldi, Darwin appear on the edge of the lunar disk. These are essentially small crater seas with a dark bottom. The first of them is the largest crater visible from Earth: its diameter is 255 km.
After the full moon, the Moon begins to wane and previously familiar areas, under different lighting, reveal new, previously invisible details. Therefore, it makes sense to study the topography of the Moon not only between the new moon and the full moon, but at any time when the Moon is visible in the sky.
> How to watch the moon
Moon watching: is it possible to see meteors, eclipses, aurora and comets, when is the best time to observe, cycles and phases of the Moon, map of the lunar surface, telescope, filters.
The Moon seems to be the most accessible object to observe in the sky. Sometimes it appears in the form of a thin crescent, sometimes it disappears completely, and on some days it shines as a huge sphere, eclipsing the stars. These are not the whims of the luminary, but the phases of the Moon and the distance of the satellite to the Earth, which changes as it passes along an elliptical orbit around the planet. We are accustomed to this night neighbor, so we pay attention only during periods of lunar eclipse. But the Moon hides many interesting objects. Below you will find out when is the best time to look at the Moon, whether you can see meteors and what interesting things are located on the surface. At the very end, admire amazing photos of the Moon with craters and seas. Don’t forget also that on the site you can use telescopes and observe the Moon online in real time.
The moon is the only one natural satellite Earth, which is also the brightest object in the night sky. The gravity there is 6 times lower than on Earth, and the difference between night and day temperatures exceeds 300˚C. A complete revolution of the Moon around its axis takes 27.3 Earth days. In this case, the rotation trajectory and its angular speed are stable and equal to the speed of its rotation around the Earth. That is why the observer constantly sees only one hemisphere of the satellite. The other side (the far side of the Moon) is always hidden from us.
When is the best time to watch the Moon?
Despite the fact that this fact, at first glance, seems complete nonsense, its veracity has been proven by the experience of thousands of observers. The full moon (moon phase) is a bad time to explore the moon. At this time, the contrast of details on the surface is reduced to zero, so it is almost impossible to see them. IN lunar month There are two periods conducive to research. This is the time after the new moon, which ends two nights after the first quarter. Here the Moon is perfectly visualized in the evening.
Lunar "evolution"
The second period begins a couple of days before the last quarter and ends on the new moon. At this time, the lunar shadows are so long that they are perfectly visualized on mountainous terrain. In addition, the atmosphere in the morning is much calmer than in the evening, providing clear and stable images with plenty of small parts.
In any case, it is important to take into account the height of the Moon above the horizon. The lower the Moon is, the denser the air that overcomes the moonlight. This results in a large number of distortions and lower picture quality. The satellite's height above the horizon varies from season to season.
Before moon observations Determine the time of optimal visibility using any planetarium program.
The trajectory of the Moon around the Earth has the shape of an ellipse. The average distance between the centers of the Moon and the Earth is 384,402 km, but the actual distance constantly varies from 356,410 to 406,720 km. In this regard, the apparent size of the Moon also changes - from 29" 22"" at apogee to 33" 30"" at perigee.
Of course, the observer should not wait for the moment when the Moon is closest to the Earth. Just remember that at perigee you can study subtle features on the moon's surface that are hidden during normal times.
When starting a study, you need to point the telescope at any point near the terminator - the line dividing the Moon into light and dark halves. During the waning Moon, the terminator shows the place of sunset; during the waxing Moon, the terminator shows the place of sunrise.
Photograph of the Moon through an amateur telescope. Image obtained through a 125 mm refractor
Moon observation at the terminator will allow the researcher to study the structure of mountain peaks illuminated by sunlight. At the same time, the lower part of the mountains hides in the shadows. The landscape near the terminator line is changing in real time. Therefore, many hours of observation of any attraction will be rewarded with a magnificent spectacle.
It is important! When exploring the moon between the last or first quarter phases and the full moon, turn on a moderately bright light white behind your back. Of course, the light source should not be located in the direct line of sight, hit the eyes or glare on the eyepiece. This will allow you to maintain better daytime vision and see many details on the satellite's surface.
Necessary equipment
To observe the moon and get high quality photos, you need to know how to choose or buy a telescope. The moon is an object with a very bright glow. During observations through a telescope, it can easily blind the researcher. There are several ways to make observations more comfortable by reducing the brightness of the Moon. For example, you can use a variable density polarizing or neutral gray filter. It is more reasonable to use the first one, since with it you can change the level of light transmission (1% - 40%). This is convenient because the level of lunar glow directly depends on its phase and the magnification used. And when using an ND filter, the image of the Moon will constantly change from too dark to too bright.
A variable brightness filter will smooth out these differences, allowing you to set required parameter brightness
It is not customary to use color filters during lunar exploration. The only exception is the red filter, which can be used to increase the contrast of areas with a high basalt content. In addition, it stabilizes images in unstable atmospheres and minimizes lunar glare.
If you decide to study the Moon, purchase a lunar atlas or map. In addition, use the Virtual Atlas of the Moon application, which will provide you with all the information in preparation for your exploration.
For experienced astronomers, we offer you a more detailed moon map, where all surface formations are displayed:
(Image size: 2725 x 2669, Weight: 1.86 mb).
Details on the Moon depending on equipment
Since the Moon is located close to the Earth, astronomy lovers love to observe it both with the naked eye and with the help of special equipment. Thus, even with the naked eye you can see the characteristic ashy hue of the Moon, which is especially obvious in the mornings on a waning Moon and in the evening twilight on a waxing Moon. In addition, the general features of the satellite can be easily observed.
Image of the Moon obtained through a 114 mm telescope + 2x Barlow lens
Using a small telescope or binoculars, you can take a closer look at lunar craters, seas, and mountain ranges. Believe me, you will find a lot of interesting things here!
As the aperture increases, the purely visible objects also increase. Through a telescope with an aperture of 200 - 300 mm, you will be able to study fine details on the surface of large craters, explore the structure of mountain ranges, and see numerous folds, grooves, and chains of small craters.
It is extremely difficult to calculate the capabilities of each specific telescope, since decisive role the state of the atmosphere plays a role here. Most often, at night, the maximum limit of a large telescope is 1”. Periodically, the atmosphere calms down for a couple of seconds. And at this time, the observer must use his technique to the limit of its capabilities. For example, on a clear and calm night, using a 200 mm telescope, you can see craters with a diameter of up to 1800 meters, and using a 300 mm instrument - 1200 meters.
How to Observe the Moon
Typically, observations of the Moon are carried out along the terminator, since this line has increased contrast of lunar details. And the play of shadows makes the landscapes of the lunar surface truly magical. At the same time, you should not be afraid of experiments. Play with magnification and choose what will be optimal for your specific viewing conditions. Most often, you will need a set of 3 eyepieces.
A low magnification eyepiece, often called a search eyepiece. Used for comfortable exploration of the full lunar disk and general acquaintance with the sights on the surface of the satellite. In addition, you can use it to observe lunar eclipses and organize lunar excursions for friends.
An eyepiece with medium magnification (from 80x to 150x) is the most popular. Extremely useful in unstable atmospheres.
A powerful eyepiece (2D-3D) is used for professional study of the Moon with the maximum capabilities of optical technology. Can only be used in an excellent atmosphere and absolute thermal stabilization of the telescope.
Lunar through a 300 mm telescope and 2 Barlow lenses
You can increase the efficiency of your observations using Charles Wood's list of the 100 best lunar objects. In addition, read the articles in the “Unknown Moon” series, which are devoted to an overview of the attractions on the surface of the satellite.
Surely, you will be carried away by the search for tiny craters that can only be seen at the limit of the telescope's capabilities.
Be sure to keep a diary of observations. In special columns, enter data about the time and phase of the Moon, observation conditions, the state of the atmosphere, and the magnification used. You can also make sketches here
What to see on the Moon
Craters are objects that dot the entire lunar surface. The term comes from the Greek word meaning "cup". Most often, lunar craters are formed from impacts of cosmic bodies on the surface of the satellite.
Lunar maria are dark areas that contrast with the rest of the Moon's surface. They are essentially lowlands, occupying up to 40% of the surface area visible from Earth. During a full moon, dark spots give the moon a “face.”
Furrows are valleys on the surface of the Moon. They reach many hundreds of kilometers in length, 3500 meters in width, and up to 1000 meters in depth.
Folded veins - outwardly look like ropes. They are formed as a result of compression and deformation from the subsidence of the seas.
Mountain ranges are mountains on the surface of the Moon. Their height varies from 100 to 20,000 meters.
The domes are the real secret of the Moon. There is still no reliable data about their nature. Today there is evidence of a couple of dozen domes, which are small (up to 15 km in diameter) smooth and round elevations.
10 most interesting lunar objects
T (moon age in days) - 9, 23, 24, 25
Located in the northwestern region of the Moon. You can even observe it with binoculars with 10x magnification. Using a medium magnification telescope, it is visualized as an amazing object with a diameter of 260 km and blurred edges. There is a scattering of small craters on the flat bottom of the Gulf
T – 9, 21, 22
It is one of the most famous lunar objects that can be explored with a small telescope. The crater is surrounded by a system of rays that radiate 800 km from the crater. The depth of the crater is 3.75 km, diameter is 93 km. When the Sun rises or sets over the crater, the observer can enjoy magnificent scenes.
T - 8, 21, 22
It is a tectonic fault that can be easily visualized with a 60mm telescope. The length of the object is 120 km. It is located at the bottom of an ancient destroyed crater, traces of which you will see at the eastern edge of the Straight Wall.
T - 12, 26, 27, 28
A huge volcanic dome that can be observed with a 60mm telescope or powerful astronomical binoculars. The diameter of the hill is 70 km, and its highest point located at an altitude of 1.1 km from the lunar surface.
T - 7, 21, 22
A mountain range whose length is 604 km. It can be seen with binoculars, but for more serious observations you will need a telescope. Some peaks are 5 km high. And in certain parts of the mountain range there are deep grooves.
T - 8, 21, 22
Visualized with binoculars, Plato's crater is one of the most popular objects among amateur astronomers. The diameter of the crater is 104 km. “Great Black Lake” is the poetic name given to the crater by Jan Hevelius, a Polish astronomer (1611-1687). Indeed, with the help of an amateur telescope or binoculars, the object is visualized as a large dark spot contrasting with the light surface of the Moon.
T - 4, 15, 16, 17
A pair of small craters, which can be observed with a telescope of 100 mm. Messier is an elongated object with a size of 11 by 9 km. Messier A is a little larger - 13 by 11 km. To the west there is a pair of light rays, the length of which exceeds 60 km.
T - 2, 15, 16, 17
The crater is visualized through small binoculars, but only a powerful telescope with serious magnification turns it into an amazing object. The bottom of the crater is dome-shaped, dotted with cracks and grooves.
T - 9, 21, 22
It is one of the most famous lunar objects, which became known for its huge system of rays around the crater. The system extends over 1500 km. You can even see the rays with amateur binoculars.
T - 10, 23, 24, 25
The crater is oval in shape and is 110 km long. Excellent visualization in 10x binoculars. Using a telescope, you can see a huge number of crevasses, hills and mountains at the bottom of the crater. You will also definitely see that the walls of the crater are partially destroyed. At the northern edge is the Gassendi crater, which makes the object look like a diamond ring.
From the author
So what should you do if your skies are currently gloomy or you don't have any astronomy equipment? Our portal has taken care of this too. Presents to your attention an interactive tool that allows you to observe the Moon in real time.
Photos of the Moon taken by amateur astronomers:
Since childhood, the idea has been formed in our heads that the Sun can be seen during the day, and the Moon at night. Field of activity" heavenly bodies was clearly distributed. However, a strange fact is evident: quite often the night star is visible during the day. Paradox or just gaps in our astronomical knowledge? Definitely the second option. And in our article we in simple language Let's try to explain why the Moon is visible during the day.
Reasons for the visibility or invisibility of objects in the sky
Various objects in the field of view from the Earth are noticeable to varying degrees. The Sun is incomparably brighter against the background of the daytime sky than the Moon at night. At the same time, we remember that the distance from the satellite to the Earth is much smaller, cosmically smaller. Understanding this is important when we examine the question of why the Moon is visible during the day.
There is such a thing as brightness - stellar magnitude. In order for them to be clearly visible during daylight hours, their brightness must be much greater than that of the daytime sky. So, the clear sky during the day is 9.5, and the moon is 12.7. The excess is obvious, and therefore the satellite should be noticeable by all factors, although not in strong contrast with the background. This is the simplest and most understandable explanation for us, not astronomers, as to why the Moon is visible during the day.
When can the Moon and Sun be seen at the same time?
We have perfectly learned from childhood that the Moon revolves around the Earth, and the Earth revolves around the Sun. To this we must add that the planet also moves around its axis. The celestial bodies seem to be in a constant dance, changing positions. And this is extremely important to take into account when figuring out when and why the Moon is visible during the day.
Taking into account all the conditions, it is possible to see the Moon and the Sun together only on a full moon. Moonrise also coincides at this time. The rest of the time, the satellite should theoretically be visible during the day. But other factors also play a role here. The Moon is more visible in the daytime sky during periods when it approaches its full phase and its angular distance from the Sun is greater. In other phases, growing and aging, the side of the satellite illuminated by the Sun is small and turned towards it. Accordingly, the narrow strip of the young month will be extremely difficult to see during the day. This is why the Moon is not always visible during the day: sometimes it is simply difficult to notice.
Properties of the atmosphere and contrast of astronomical bodies
The atmosphere of our planet daytime has a blue color (we immediately imagine the appearance of a clear sky). Also, due to scattered particles of light from the Sun, it is bright. It is the brightness of the day that drowns out the brightness of the Moon. The latter, due to the balls of the atmosphere, could also be visible to us in blue color, however, low contrast prevents this from happening. If the Moon appears in the sky during the day, it is most often a pale spot that is easy to miss. However, this did not stop astronomers from conducting their studies of the surface of the satellite even during daylight hours.
Thus, we understand that the light in the atmosphere of our planet makes it difficult to see the noticeable outline of the Moon, as at night. For a significant part of its cycle, the satellite is in a position where it is clearly visible near the Sun during the daytime. Therefore, the more pressing question is not why the Moon is visible during the day, but why it is not so clearly visible.
Experiments with photographs of the lunar surface
Despite the pale outline, the Moon is visible to the naked eye during the day. Astronomers could not miss this moment: since it can be seen without equipment, then what will happen if technology is used? Experiments began with photographing the surface of the Moon during the day. It must be said that their quality was quite good, considering the atmospheric conditions. The first such photograph was taken using a conventional digital camera attached to a telescope. The result was as expected: due to the low contrast of the Moon against the background of the daytime sky, its image was unclear.
The experiment was continued under the same conditions and with the same equipment, but in the mode black and white flowers. The photo turned out to be somewhat more contrasty. To improve the image, we used the usual Photoshop. The processing made it look like one of the photographs taken during evening shooting. Thus, it became possible to see relief objects in the photo. It is noteworthy that both large craters (Grimaldi, Gassendi, Aristarchus) and smaller ones are clearly visible.
The experiments cited as an example with filming the lunar surface during the day prove that the satellite is not easy to see during daylight hours. It can even be explored from an astronomical perspective. We believe that the question of why the Moon is visible during the day has already received a completely clear answer.
conclusions
There are many mysteries for us in space, but humanity has managed to study the nearest objects to some extent. The night luminary, the satellite of the Earth, are objects of romantic views, accustomed to contemplating it only in the dark. However, the Moon can also be seen during the day, sharing the sky with the Sun.
In our article, we tried to understand in simple terms why the Moon can be seen during the day and what is the reason for the fact that sometimes we do not notice it. We hope that we have helped you expand your knowledge of the world around you.
The Moon is the closest celestial body to Earth, so it can be observed using a very modest telescope or even binoculars.
The moon can be successfully photographed or filmed with a video camera right from home. The Moon is the Earth's natural satellite and the brightest object in the night sky. The gravity on the Moon is 6 times less than on Earth. The difference between day and night temperatures is 300°C. The Moon rotates around its axis 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 reverse side The moon is always hidden from our eyes.
But here’s the question: the Moon has already been studied so thoroughly by automatic spacecraft (read about this on our website: Exploring the Moon), people visited it (read on our website: The first flight to the Moon, About the first people who visited the Moon), that doubts arise: can we really be witnessing some still unknown phenomena today? Or residual lunar tectonism ended long ago, and the Moon is just big frozen stone ball , orbiting our planet? Let's not be skeptics and hope that everything in the Universe lives and is in motion, and if so, then many discoveries lie ahead. Today there are many astronomy enthusiasts who regularly conduct visual, photo and video observations of many objects and details of the lunar surface. There is even an International Organization ALPO (Association of Moon and Planetary Observers), which works on real scientific programs. The sight of the mysterious lunar mountains and craters changing their outlines with changes in the position of the terminator is one of the most vivid impressions from all amateur astronomy... Even the naked eye is enough to see a lot of pleasant details. For example, the “ash light”, which is visible when observing the thin crescent Moon, is best visible in the early evening (at dusk) on a waxing Moon or early in the morning on a waning Moon. Also, without an optical instrument, you can make interesting observations of the general outlines of the Moon - seas and land, beam system, surrounding the Copernicus crater, etc. By pointing binoculars or a small telescope with low magnification at the Moon, you can study in detail the lunar seas, the largest craters and mountain ranges.
Galileo was the first to observe the Moon through a telescope and left records of his observations. Even with his small and imperfect telescope, he was able to detect mountains, craters and large dark areas that seemed to him like big seas, that’s why he called them maria (Latin for “sea”).
When is the best time to observe the Moon?
There are two most favorable periods for observing the Moon: shortly after the new moon and two days before the last quarter and almost before the new moon. These days, the shadows on the surface of the Moon are especially long, which is clearly visible on the mountainous terrain. In the morning hours the atmosphere is calmer and cleaner. Thanks to this, the image is more stable and clear, which makes it possible to observe finer details on its surface.
An important point to observe is the height of the Moon above the horizon. The higher the Moon, the less dense the layer of air that the light coming from it overcomes. Therefore, the image quality is better - less distortion, but the height of the Moon above the horizon varies depending on the season.
So, let's begin our observations: point your telescope at any point near the line that divides the Moon into two parts - light and dark. This line is called Terminator, being the border between day and night. During the waxing Moon, the terminator indicates the place of sunrise, and during the waning Moon, the location of sunset.
Observing the Moon in the terminator area, you can see the tops of the mountains, the landscape along the terminator line, which changes in real time - an amazing sight!
Objectives of lunar observations
- Studying the details of the lunar relief;
- clarification of the theory of lunar motion;
- observations Lunar eclipses;
- surface patrol surveillance(detecting possible flashes from meteoroids falling on the surface of our satellite) and other observations.
What to observe on the Moon?
The most common formations on the lunar surface. They get their name from the Greek word meaning “bowl.” Most lunar craters are of impact origin, i.e. formed as a result of the impact of a cosmic body on the surface of our satellite.
Dark areas on the lunar surface. These are lowlands that occupy 40% of the total surface area visible from the Earth.
During the full moon, the dark spots that form the so-called “face on the Moon” are precisely the lunar seas.
Lunar valleys reaching hundreds of kilometers in length. Often the width of the furrows reaches 3.5 km, and the depth is 0.5–1 km.
Folded veins- they resemble ropes.
Mountain ranges- lunar mountains, the height of which is 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.
Almost any telescope with a standard set of eyepieces is suitable for observations. The mounting is also better than the standard one.
The light from the Moon in a telescope can be quite powerful, so do not forget about eye safety - use light filters. It is better to use special lunar light filters; they have a greenish tint and transmit 20% of the light.
For example, a Celestron 127 telescope with a standard equatorial mount.
Included with it are good quality eyepieces for lovers of sky observations and a standard three-fold Barlow lens. The 20mm eyepiece and Barlow lens achieve 150x magnification.
Photographing the Moon is not difficult, but to do this you will need a T-adapter for a DSLR camera or a simple camera.
When using a DSLR camera and a T-adapter, very good pictures are obtained.
Where should you start observing the Moon?
First, with a good map of the Moon. But if you have an Internet connection, then use Interactive map Moons. The only difficulty in using this card may be lack of knowledge of English.
Secondly, it is advisable to purchase an atlas of the Moon and study it.
There is also the “Virtual Atlas of the Moon” program, where you can see the Moon in real form.
The most interesting lunar objects
Available for observation with a small telescope. The diameter of the crater is 93 km and the depth is 3.75 km. Sunrises and sunsets over the crater are an amazing sight!
Mountain range with a length of 604 km. Easily visible with binoculars, but a telescope is needed to study it in detail. Some peaks of the ridge rise 5 or more kilometers above the surrounding surface. In some places the mountain range is crossed by furrows.
We can even see it through binoculars. It is a favorite object of astronomy lovers. Its diameter is 104 km. 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.
The oval crater, stretching for 110 km, is accessible for observation with binoculars. Through a telescope it is clearly visible that the bottom of the crater is dotted with numerous crevices, hills, and slides. In some places the walls of the crater have been destroyed. At the northern end is the small crater Gassendi A, which, together with its older brother, resembles a diamond ring.
How to watch a lunar eclipse
The picture shows a view of the Moon during a lunar eclipse.
Moon eclipse- an eclipse that occurs when the Moon enters the cone of the shadow cast by the Earth. The diameter of the Earth's shadow spot 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 may be obscured. At each moment of the eclipse, the degree of coverage of the Moon's disk by the earth's shadow is expressed by the eclipse phase F. The magnitude of the phase is determined by the distance 0 from the center of the Moon to the center of the shadow. Astronomical calendars give the values of Ф and 0 for different moments of the eclipse.
In the picture you see the phases of a lunar eclipse.
When the Moon completely enters the Earth's shadow during an eclipse, it is said to be complete lunar eclipse, when partially - about private eclipse Two necessary and sufficient conditions for the occurrence of a lunar eclipse are the full moon and the proximity of the Earth to the lunar node. A lunar eclipse can be observed over half of the Earth's territory (where the Moon is above the horizon at the time of the eclipse). During an eclipse (even a total one), the Moon does not disappear completely, but turns dark red. This fact is explained by the fact that the Moon, even in phase total eclipse continues to light up. Sun rays, passing tangentially to the earth's surface, are scattered in the earth's atmosphere and, due to this scattering, partially reach the moon. Since the earth's atmosphere is most transparent to rays of the red-orange part of the spectrum, it is these rays that reach the surface of the Moon to a greater extent during an eclipse, which explains the color of the lunar disk.
The picture shows a diagram of a lunar eclipse.
An observer located on the Moon at the moment of a total (or partial, if he is on the shadowed part of the Moon) lunar eclipse will see a total solar eclipse(eclipse of the Sun by the Earth).
Every year there are at least two lunar eclipses, however, due to the mismatch of the planes of the lunar and earth's orbits, their phases differ. Eclipses repeat in the same order every 6585 days (or 18 years 11 days and ~8 hours - a period called saros); Knowing where and when a total lunar eclipse was observed, you can accurately determine the time of subsequent and previous eclipses that are clearly visible in this area. This cyclicality often helps to accurately date events described in historical records.
The longest lunar eclipse lasted 1 hour. 47 min. It happened on July 16, 2000. The eclipse was observed in China and throughout Asia.
Every detail during a lunar eclipse can be seen through binoculars or a telescope. But observations can also be made with the naked eye. The accuracy of observations, of course, increases when observing through a telescope. Write all notes in a notebook (a journal of eclipse observations).
