How are solar and lunar eclipses formed? What does the schematic look like?

Causes of solar eclipses (pictures)

A solar eclipse is when the moon moves between the sun and the earth. If the three are in a straight line, the moon will block the sun from hitting the earth. The light and the dark shadow behind the moon just fall on the earth, and a solar eclipse occurs. People in the moon shadow (moon shadow: the shadow cast by the moon on the earth) on the earth begin to see the sunlight gradually weakening, the sun's surface is covered by a round black shadow, the sky turns dark, and when it is completely covered, it can be seen in the sky After a few minutes, the brightest stars and planets began to shine and regain their circular shape as sunlight gradually emerged from the edge of the moon's dark shadow. Because the moon is smaller than the Earth, only people in the moon's shadow can see the eclipse. A total solar eclipse occurs when the moon completely blocks the sun, a partial solar eclipse occurs when it partially blocks the sun, and an annular solar eclipse occurs when it blocks the central part of the sun. The duration of a total solar eclipse will not exceed 7 minutes and 31 seconds. The longest annular solar eclipse lasts is 12 minutes and 24 seconds. In order to extend the observation time of the total solar eclipse, a French astronomer flew a supersonic aircraft to chase the moon's shadow, extending the observation time to 74 minutes. Our country has the oldest records of solar eclipses in the world, with exact records of solar eclipses dating back more than 1,000 BC. Solar eclipses usually occur on the first day of the lunar calendar.

Edit this paragraph for scientific explanation

Solar and lunar eclipses are typical examples of light propagating in straight lines in celestial bodies. A solar eclipse does not occur every time the moon moves between the sun and the earth. A solar eclipse

Two conditions need to be met for a solar eclipse to occur. First, solar eclipses always occur on the first day of the new moon (the first day of the lunar calendar). Not all solar eclipses are bound to occur because the moon's orbit (the ecliptic) and the sun's orbit (the ecliptic) are not on the same plane. The angle between the ecliptic plane and the ecliptic plane is 5°9′. If on the new moon, both the sun and the moon move near the intersection of the ecliptic and the ecliptic, and the sun is at a certain angle from the intersection (solar eclipse limit), a solar eclipse will occur. This is the second condition that must be met. Since the orbits of the moon and the earth are not perfect circles, the distance between the sun and the moon and the earth is sometimes close and sometimes far away. Therefore, the shadow formed by the sunlight being blocked by the moon can be divided into the umbra and the pseudo umbra (the distance between the moon and the moon) on the earth. (formed when the Earth is farther away) and the penumbra. Observers can see a total solar eclipse within the umbral range; an annular solar eclipse can be seen within the pseudo-umbral range; and only a partial solar eclipse can be seen within the penumbral range. There are many mountains on the surface of the moon, and the edges of the moon are uneven. When the valley on the edge of the moon fails to completely block the sun at the moment of eclipse or solar radiation, the unblocked part forms a luminous area, like a crystal "diamond"; the surrounding light red aperture forms the "ring" of a diamond ring. , overall, it looks like a diamond ring inlaid with bright gems, called a "diamond ring". Sometimes many particularly bright rays or points of light are formed, as if a string of pearls are inlaid around the sun, called "Bailey's beads" (Bailey is a French astronomer). Whether it is a partial solar eclipse, a total solar eclipse or an annular solar eclipse, the time is very short. The area where you can see a solar eclipse on the earth is also very limited. This is because the moon is relatively small, and its umbra is also relatively small and short. Therefore, the umbra does not sweep over a wide range on the earth and does not last long. Because the moon The average length of the umbra (373,293 kilometers) is smaller than the average distance between the Moon and the Earth (384,400 kilometers). For the entire Earth, annular solar eclipses occur more often than total solar eclipses.

Edit this paragraph Solar Eclipse Phases

When a total solar eclipse occurs, based on the positional relationship between the moon's disk and the sun's disk, it can be divided into five types of eclipses: 1. First loss. The moon moves faster than the apparent motion of the sun. The moon catches up with the sun during a solar eclipse. When the eastern edge of the moon just "contacts" with the western edge of the sun, it is called the first waning. It is the first "exocution" and the beginning of the solar eclipse 2. Eat. About an hour after the initial waning, the moment when the eastern edge of the moon and the eastern edge of the sun are "inscribed" is called an eclipse. It is the beginning of a total solar eclipse (or annular solar eclipse). For a total solar eclipse, the moon covers the entire sun. Covered, for an annular solar eclipse, the sun begins to form a ring at this time; during a solar eclipse, the positional relationship between the moon's shadow and the sun's disc when they are inscribed for the first time also refers to the positional relationship that occurs. moment. Eating occurs after the initial loss. From the beginning of the first waning period, the moon continues to move eastward, and the part of the sun's disc covered by the moon gradually increases, and the intensity and heat of the sun decrease significantly. When the western edge of the moon is inscribed with the western edge of the sun, it is called an eclipse. The direction of the sky is opposite to the east-west direction of the map. 3． Eat very much. It is the moment when the sun is most eclipsed, and the center of the moon moves closest to the center of the sun; during a partial solar eclipse, when the sun is most covered by the moon, the positional relationship between the two; during a total solar eclipse and an annular solar eclipse, when the sun is completely covered by the moon Cover the positional relationship between two centers when they are closest to each other. It also refers to the moment when the above-mentioned positional relationship occurs. 4. Generate light. The moment when the western edge of the moon and the western edge of the sun are "inscribed" is called photonization, which is the end of a total solar eclipse; the period from eclipse to photonization generally lasts only two to three minutes, and the longest is no more than seven. It takes a minute and a half for a solar eclipse. After the eclipse, the moon continues to move eastward relative to the sun. 5. Round. About an hour after the onset of light, when the western edge of the moon "touches" the eastern edge of the sun, it is called a complex circle. From this time on, the moon completely "separates" from the sun, and the solar eclipse ends. Both a total solar eclipse and an annular solar eclipse have the above five processes, while a partial solar eclipse only has three processes: initial waning, eclipse, and full circle. There is no eclipse or light generation.

Another explanation from Cihai: During a solar eclipse, the positional relationship between the moon's shadow and the sun's disk when it circumscribes for the second time also refers to the moment when this positional relationship occurs. The re-circulation is the end of the eclipse process.

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Why did part of the sun disappear? This is the part of the sun that happens to be hiding behind the moon at that time. This was the first partial solar eclipse of 2005 and the last total solar eclipse observable until March 2006. During a solar eclipse, the sun, moon and earth are in a straight line. This total solar eclipse first appeared in the South Pacific, and the area where the partial eclipse can be observed spans South America and North America to the south. The scene above was captured with a handheld digital camera last Friday. After a whole day of rain in the Holly Mountains of North Carolina, USA, the partially eaten sun temporarily broke through the dark clouds in the sky. After taking a series of images, the best photo of the eclipse was digitally combined with a less good photo that showed an airplane. Solar Eclipse

Solar Eclipse

Edit this paragraph Significance and Value

The main reason why a total solar eclipse is valued is that it has great astronomical observation value. Many of the major astronomical and physical eclipses in the history of science were made by taking advantage of the opportunity of a total solar eclipse, and only by such an opportunity. The most famous example is a total solar eclipse in 1919, which confirmed the correctness of Einstein's general theory of relativity. In 1915, Einstein published the general theory of relativity, which was considered extremely difficult to understand and extremely incredible at the time. This theory predicted that light would bend in a huge gravitational field. The strongest gravitational field that humans can come into contact with is the sun, but the sun itself emits very strong light. It is impossible to tell whether the faint starlight in the distance has turned when it passes near the sun. But if a total solar eclipse occurs and the sun's rays are blocked, you can measure whether the light has turned and how far it has turned. The opportunity presented itself in 1919, but the total solar eclipse took place in the South Atlantic, which was very far away and very difficult. British astronomer Eddington set out with an enthusiastic and curious observation team. The observation results were very consistent with Einstein's pre-calculated results, and the theory of relativity has since been recognized by the world. In China, the first two total solar eclipses could only be seen in remote areas. The first time was in 1980, which was only visible in the Ruili area of ??Yunnan on the China-Myanmar border. At that time, the author had just entered junior high school and was an enthusiastic young astronomy enthusiast. Unfortunately, he had no financial means and could only get his addiction through the magazine "Astronomy Enthusiasts". The other time was after the Spring Festival in 1997, which was visible on the Sino-Russian border and the northernmost point of China, Mohe. That time, the author went to interview on the order of the newspaper, and at the same time, he also fulfilled his childhood dream. The scale of that observation was beyond imagination. Astronomers and astronomy enthusiasts from all over the world crowded a small town in northern Xinjiang, which is usually inaccessible, even more lively than the New Year. Because the number of people greatly exceeded the reception capacity of the town, people only Can camp on trains and buses. It was still winter there at that time, and the temperature during the day was about minus 25°C, and at night it could reach minus 40°C. The dripping water turned into ice, and people couldn't even find water to wash their faces and gargle. Despite this, none of the observers regretted it, and none of them was not excited. They all regarded seeing the total solar eclipse with their own eyes as a rare and precious memory in their lives. Astronomical phenomena such as total solar eclipse do not have any direct relationship with people's daily life, eating, drinking and diarrhea. However, it represents an ultimate humanistic concern, an extreme love for nature, and an eternal curiosity and awe for the iron laws of nature that govern all things. It is indispensable for a country and a nation. These cares, these loves, these wonders, these awes.

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1: China has a long history of observing solar eclipses. Someone observed a solar eclipse as early as 1948 BC. China had a solar eclipse more than 2300 BC

The most advanced astronomical observatory at that time. China has always attached great importance to the prediction of solar eclipses. It is said that an astronomical official in the Xia Dynasty was beheaded as a warning to those who neglected their duties because he was indulged in wine and debauchery and failed to report a solar eclipse. China has the earliest, most complete and richest solar eclipse records in the world. There are more than 1,000 records of solar eclipses in historical materials (excluding oracle bone inscriptions) from ancient books (up to the Qing Dynasty) alone. The earliest record was a solar eclipse that occurred in 1948 BC. The "Book of Songs" records in detail the solar eclipse that occurred on September 6, 776 BC: "At the turn of October, the first day of the lunar month was Xin Mao, and the sun had an eclipse." The world's astronomers generally recognize that ancient Chinese solar eclipse records It has the highest degree of credibility and has left precious scientific and cultural heritage to the world. Ancient China's Xia, Shang and Zhou dynasties have a long history and lack of precise written records, so it is difficult to accurately date them. Solar eclipses are like a very accurate historical clock, which can help determine the time of some historical events. 2: A solar eclipse stopped a war in the ancient West. The most famous story in the West was recorded in 585 BC. The Mitis and Libyan tribes were fighting, and in the middle of the battle, the sun suddenly disappeared. The people of the two tribes were afraid of the coming disaster, and finally reached a beautiful result - peace and intermarriage between the two tribes. Regarding the view of the solar eclipse phenomenon, except for the Tahitians who regard the solar eclipse as a positive meaning, other countries interpret it negatively.

For example, in more than 600 BC, when Athens was attacking a certain tribe, it was too afraid to move forward because of an eclipse. Because it delayed the attack, it allowed the enemy to take advantage of this period to prepare. As a result, when the Athenian army attacked the enemy time, but was defeated. 3: Various ethnic groups have different explanations for total solar eclipses, such as tengu eating the sun, wolves chasing the sun, etc., and have their own solutions. In ancient China, solar eclipses

People used to beat gongs and drums to deal with them; since the duration of a total solar eclipse is usually very short (at most seven and a half minutes), after people beat the drums, the sun may It will reappear immediately, thus eliminating people's panic. China has recorded solar eclipses very early. Many stones were excavated from tombs in the Han Dynasty. Many figures of the sun, moon and stars were carved on these stones. One of the paintings had "the sun and the moon combined", which means that the sun and the moon are superimposed on each other. Together, this is the record of the solar eclipse at that time. The Chinese scientific explanation for a solar eclipse is that yin invades yang. China has known for a long time that the moon, which is regarded as "yin", blocks the sun, which is regarded as "yang", causing a solar eclipse. In ancient times, there was a saying that "when the moon is waxing, there will be an eclipse." This means that lunar eclipses always occur when the moon is full. When a solar eclipse occurs, the ancient Chinese court will also take action; the Chinese believe that the sky represents nature, and the sun has the highest status in nature. The emperor is called the Son of Heaven, which means that he is sent by God to manage the people. Since the sky represents the emperor's father, it will warn its earthly agent, the emperor, through phenomena on the surface of the sun, telling him clearly what he has done wrong, what things he should be careful about, etc.; thus, through various signs, Come out, the solar eclipse is a situation that is often exploited. According to the records of Bi Zhen Hall in ancient books, whenever a solar eclipse occurred in the Han Dynasty, the emperor would not go to the main hall for morning court, but to the small hall next to the side hall for morning court, and everything was kept simple. According to legend, the solar eclipse is called "Tengu swallows the sun." The scientific explanation for "Tengu swallows the sun" is a solar eclipse. A solar eclipse is a classic example of light traveling in a straight line through a celestial body. Since the orbits of the moon and the earth are not perfect circles, the distance between the sun and the moon and the earth is sometimes close and sometimes far away, so the shadow formed by the sunlight being blocked by the moon can be divided into the umbral shadow and the pseudo umbral shadow (the distance between the moon and the moon) on the earth. (formed when the Earth is farther away) and the penumbra. Observers can see a total solar eclipse within the umbral range; an annular solar eclipse can be seen within the pseudo-umbral range; and only a partial solar eclipse can be seen within the penumbral range. There are many mountains on the surface of the moon, and the edges of the moon are uneven. At the moment of eclipse or illumination, when the valley on the edge of the moon fails to completely block the sun, the unblocked part forms a luminous area, like a crystal "diamond"; the surrounding light red aperture forms the "ring" of a diamond ring. ”, overall, it looks like a diamond ring inlaid with bright gems. Sometimes many particularly bright rays or light spots are formed, as if a string of pearls are inlaid around the sun, called Bailey's beads (Bailey is a French astronomer).

Edit this section for future predictions

1: China has entered a period of high incidence of solar eclipses and can enjoy two solar eclipses in the next four years: China will usher in the first total solar eclipse of this century. In the next four years, the Chinese public will also be able to enjoy three rare solar eclipses, including one total solar eclipse and two annular solar eclipses. Astronomical experts said that it is rare for so many solar eclipses to occur in five years. On July 22, 2009, a more spectacular total solar eclipse occurred in China, with the total eclipse sweeping across the Yangtze River Basin in central China. This total solar eclipse can be seen in more than 40 cities in China, including Lhasa, Chengdu, and Shanghai. Compared with the total solar eclipse on August 1, this total solar eclipse will occur in a wider range and last longer, lasting 5 to 6 minutes. This situation is a rare occurrence in a century. In addition to this total solar eclipse, an annular solar eclipse also occurred on January 15, 2010. The public in Yunnan, Sichuan, Hubei, Anhui and other places can see the annular solar eclipse. On May 21, 2012, an annular solar eclipse will be staged again, and the public in Guangxi, Guangdong, Fujian, Hong Kong and Macau can enjoy it. 2: On August 1, 2008, a total solar eclipse occurred in China from Altay, Xinjiang, through Hami, Jiuquan, Xi'an and Zhengzhou. It started at around 18:20 Beijing time and lasted for about two minutes. This is the first total solar eclipse to occur in China in the 21st century. 3: January 4, 2010: Partial solar eclipse, visible in Xinjiang before sunset June 2: Partial solar eclipse, at dawn. Visible in parts of the Northeast. Shenyang. Changchun. Harbin eclipse sunrise

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The following is the number of solar eclipses that occurred worldwide in the 20th century (1901-1999): Partial solar eclipses 78 < /p>

Partial solar eclipse (14 photos), 73 annular solar eclipses, 71 total solar eclipses, 6 mixed solar eclipses, a total of 228

Edit this paragraph to observe

Bad membrane is currently the most popular, 0.012 mm thickness Visual inspection: 5.0 Light reduction 10000 times Photography: 3.8 During a solar eclipse, the sun will not emit any special rays. Observations of solar eclipses are often misinterpreted. The Sun does not predict an eclipse on Earth and does not emit other rays, so there is no harm in staying outdoors during an eclipse. But when watching a partial solar eclipse, should you stare or take a quick glance? Although the sunlight during a solar eclipse is much weaker than usual, it is still harmful to the eyes if you look directly at it, and may damage the cornea. People stare or squint at the sun out of curiosity. Of course, a partial solar eclipse is still very dazzling. If you look at the sun for a long time, your cornea will be damaged before you know it.

Eye damage during a solar eclipse is not due to abnormalities in the sun, but because people fail to pay attention to protective measures out of curiosity. Regardless of whether a solar eclipse occurs or not, do not look directly at the sun; do not use so-called "sunglasses"; do not use "sunglasses", even several stacked on top of each other; do not look at the image of the sun in mirrors or water; use size 14 Weld a mirror to view the sun; view with a specially coated Mylar mirror, which can be obtained from a famous planetarium or science museum; construct an aperture projector. A simple way to observe the solar eclipse

Warning: It is a big misunderstanding to directly wear sunglasses (sunglasses) to observe the total solar eclipse. This is because the lenses have a focusing effect. If the sunglasses are too close to the eyes, the sunlight will focus the eyeballs. Burns, severe cases may cause blindness. It is not advisable to observe directly with the naked eye. The correct way is to take off the sunglasses, hold them at an arm's length from the eyes, and observe the lenses from the side. In addition, observation using small hole imaging is also a good method. Remember that the basin reflection method is not a scientific method.

Notes

1. It is strictly prohibited to promote feudal superstition in disguised form during natural phenomena, maliciously confuse the masses, and undermine the unity of the nation and the country. 2． Do not watch in streets, roads or other dangerous places to avoid paying too much attention to the solar eclipse and endangering your life. Pay attention to safety when watching from a balcony to avoid falling. 2009.7.22 Solar Eclipse

3. Due to the solar eclipse, the temperature, the earth's magnetic field changes, and the day suddenly darkens. As a result, the physiological habits of some animals are not adapted. Pets such as dogs and cats should be leashed to prevent domestic animals from panicking and hurting people.

Lunar Eclipse Help Editor Encyclopedia Business Card

A lunar eclipse is a special astronomical phenomenon. It means that when the moon moves into the shadow part of the earth, the area between the moon and the earth will Because the sun's light is blocked by the earth, you can see that a piece of the moon is missing. At this time, the sun, earth, and moon are exactly (or almost) in the same straight line. Lunar eclipses can be divided into three types: partial lunar eclipse, total lunar eclipse and penumbral lunar eclipse. A lunar eclipse can only occur around the 15th day of the lunar calendar.

Table of contents

Overview

First introduction to lunar eclipses

Classification

Process

Total lunar eclipse process

Principle of lunar eclipse

Occurrence time

Lunar eclipse brightness

Centennial lunar eclipse chart

Historical records

Overview of related events

First introduction to lunar eclipses

Classification

Process

Total lunar eclipse process< /p>

Principles of lunar eclipses

Occurrence time

Lunar eclipse brightness

A shadow will appear on the earth in the direction away from the sun, which is called the earth's shadow. film. The Earth's shadow is divided into two parts: the umbra and the lunar eclipse

Penumbra. The umbra is the area that is not exposed to direct sunlight, while the penumbra is only partially exposed to direct sunlight. As the moon orbits the Earth, it sometimes enters the Earth's shadow, causing a lunar eclipse. A total lunar eclipse occurs when the entire Moon enters the umbra; but when only part of the Moon enters the umbra, a partial lunar eclipse occurs. Total lunar eclipses and partial lunar eclipses are both umbral lunar eclipses. During a total lunar eclipse, the moon is not completely invisible. This is because sunlight is refracted into the umbra when passing through the earth's thin atmosphere, and is projected onto the lunar surface, giving the lunar surface a reddish copper color. It seems that the path of the moon through the umbra and the atmospheric conditions of the earth at that time will cause the luminosity to be different in different total lunar eclipses. Sometimes the moon does not enter the umbra but only enters the penumbral shadow. This is called a penumbral lunar eclipse. During a penumbral lunar eclipse, the moon will be slightly dimmer, but its edges will not be obscured by the Earth's shadow.

Edit this paragraph to learn about lunar eclipses

In ancient times, people did not understand the scientific reason why lunar eclipses occur. They were as afraid of lunar eclipses as they were of solar eclipses. There are legends in foreign countries that in the early 16th century, Columbus sailed to Jamaica in South America and had conflicts with the local indigenous people. Columbus and his sailors were trapped in a corner with no food or water. The situation was very critical. Columbus, who knew something about astronomy, knew that a total lunar eclipse was going to occur that night, so he shouted to the indigenous people, "If you don't bring food, I won't give you moonlight!" At night, Columbus' words came true, and there was no moonlight. The natives were frightened when they saw this, and quickly turned their hostility into friendship with Columbus.

Edit this section to classify

Lunar eclipses can be divided into three types: partial lunar eclipse, total lunar eclipse and penumbral lunar eclipse. A partial lunar eclipse occurs when only part of the moon enters the earth's umbra during eclipse; and when the diameter of the earth's umbra is still equivalent to 2.5 times that of the moon. So when the centers of the Earth and the Moon are roughly on the same straight line, the Moon will completely enter the Earth's umbra, resulting in a total lunar eclipse. And if the moon is always only partially obscured by the earth's umbra, that is, only part of the earth's umbra is, a partial lunar eclipse occurs. There are no annular lunar eclipses on the moon. Because the size of the moon is smaller than that of the earth, the phenomenon of lunar annular eclipse does not occur. The number of lunar eclipses that occur each year is generally two, and at most three, and sometimes none at all. Because under normal circumstances, the moon either passes above the Earth's umbral shadow or leaves below it, and rarely passes through or partially passes through the Earth's umbral shadow, so lunar eclipses generally do not occur. According to observation data, the percentages of penumbral lunar eclipses, partial lunar eclipses, and total lunar eclipses in each century are approximately 36.60%, 34.46%, and 28.94%.

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The penumbral eclipse begins after the total lunar eclipse: the moon has just contacted the penumbral area, and the lunar eclipse is not visible to the naked eye at this time

. The formal process of a lunar eclipse is divided into five stages: initial waning, eclipse, eclipse, light generation, and re-eclipse. 1. The beginning of the penumbral eclipse: The moon has just contacted the penumbral area. At this time, the luminosity of the moon's surface is slightly reduced, but it is difficult to detect with the naked eye. 2. First waning (only partial lunar eclipse and total lunar eclipse): marks the beginning of the lunar eclipse. The moon slowly enters the earth's shadow from its eastern edge, and the moon and the earth's umbra are circumscribed for the first time. 3. Eclipse (total lunar eclipse only): The moon enters the Earth's umbra and incurs the umbral shadow for the first time. The Moon is just inside the Earth's umbral shadow. 4. Extreme eclipse: The moment when the center of the lunar surface is closest to the center of the Earth's umbral shadow. At this time, the lunar surface appears red copper or dark red. (Reason: Sunlight is refracted when passing through the Earth's atmosphere, causing the light to be deflected inward, but the degree of deflection of each type of light is different (dispersion). Red light has the greatest degree of deflection, is closest to the shadow of the Earth, and is reflected on the moon; In addition, due to the different content and location of dust and clouds in the atmosphere, the degree of light deflection will be different. Therefore, the moon during a total lunar eclipse is dark red, copper, or orange. In the same way, due to the refraction of the atmosphere, the sunrise and the sun are different. The setting sun is not white, but appears orange or red depending on the height due to the different degrees of atmospheric refraction.) 5. Photogenic (only total lunar eclipse): The moon moves within the Earth's umbral shadow and intersects with the Earth's umbral shadow for the second time. The eastern edge of the Moon is inscribed with the eastern edge of the Earth's umbral shadow, and the total eclipse phase ends. 6. Full circle (only partial lunar eclipse and total lunar eclipse): The moon gradually leaves the earth's umbral shadow and circumscribes the earth's umbral shadow for the second time. The western edge of the moon is tangent to the eastern edge of the earth's umbra, and the entire lunar eclipse ends. The degree of eclipse of the moon is called "eclipse fraction", which is equal to the ratio of the farthest distance from the moon's edge deep into the earth's umbral shadow to the apparent longitude of the moon at the time of the eclipse. 7. End of penumbral eclipse: The moon leaves the penumbral shadow, and the entire lunar eclipse process officially ends. There is no eclipse or light-generating process in a partial lunar eclipse, and the eclipse only represents the moment closest to the Earth's shadow. The degree of a lunar eclipse is expressed in eclipses. The eclipse fraction is equal to the ratio of the apparent diameter of the Moon at the eclipse phase to the portion of the Moon that enters the umbra at the eclipse phase. When the eclipse is extreme, if the moon is just inside the umbra, the eclipse factor is equal to 1. When the eclipse is deep, as when the moon penetrates deeper into the umbra, the eclipse is represented by a number greater than 1. The eclipse component of a total lunar eclipse is greater than or equal to 1. The food points of partial eclipses are all less than 1. The eclipse of a penumbral lunar eclipse is expressed by the ratio of the part of the moon's diameter that enters the penumbral shadow to the moon's apparent diameter. A penumbral lunar eclipse can only be detected by the naked eye when its eclipse is greater than 0.7.

Edit this section of the total lunar eclipse process

It can be divided into seven stages: 1. When the moon just contacts the penumbral shadow, it is called the beginning of the penumbral eclipse. This lunar eclipse

It is not noticeable to the naked eye at this time; 2. When the moon comes into contact with the umbra, it is called waning, and then a partial lunar eclipse begins; 3. When the moon and the umbra are in contact, it is called an eclipse, and the moon completely enters the umbra. shadow, the total eclipse begins; 4. When the center of the moon and the center of the earth's shadow are closest to each other, it is called an eclipse; 5. The second time when the moon and the umbra are inscribed are called luminescence, and the total eclipse ends at this time; 6. The second time of the moon and the umbra are When the shadow cuts out, it is called a compound circle, and the partial eclipse ends. 7. When the moon leaves the penumbral shadow, it is called the end of the penumbral eclipse. During a partial lunar eclipse, there is no eclipse and light generation. A penumbral lunar eclipse only has the beginning, end and end of the penumbral eclipse. When the moon is in the penumbra, the brightness of the moon's surface decreases very little. The darkening of the Moon's edge is visible to the naked eye only when the Moon penetrates deep into the penumbra and approaches the umbra. The moon is not completely invisible when it is within the umbral shadow. Even during totality, you can still see the red copper color on the moon's surface. This is because sunlight is refracted into the umbra when passing through the Earth's lower atmosphere and projected onto the moon.

Edit this section on the principles of lunar eclipses

The principles of lunar eclipses. On the 15th and 16th days of the lunar calendar, the moon moves to the direction opposite to the sun, a lunar eclipse

direction. At this time, if the centers of the Earth and the Moon are roughly in the same straight line, the Moon will enter the Earth's umbra, resulting in a total lunar eclipse. If only part of the moon enters the Earth's umbra, a partial lunar eclipse occurs. When the moon enters the penumbra of the earth, it should be a penumbral eclipse, but because its brightness weakens very little and is not easy to detect, it is not called a lunar eclipse. Therefore, there are only two types of lunar eclipses: total lunar eclipse and partial lunar eclipse. Lunar eclipses all occur in Wang (full moon), but not every moon has a lunar eclipse. This is the same as a solar eclipse in every moon. Under normal circumstances, the moon either passes above the Earth's umbral shadow or leaves below it. It rarely passes through or partially passes through the Earth's umbral shadow. Therefore, lunar eclipses generally do not occur. Lunar eclipses occur up to three times a year, and sometimes none occur at all. The Earth casts a shadow in the direction away from the Sun, called the Earth's shadow. The earth's shadow is divided into two parts: the umbra and the penumbra. The umbra is the area that is not exposed to direct sunlight, while the penumbra is only partially exposed to direct sunlight. As the moon orbits the Earth, it sometimes enters the Earth's shadow, causing a lunar eclipse. When the entire moon enters the umbra, a total lunar eclipse occurs; but if only part of the moon enters the umbra, only a partial lunar eclipse occurs. Total lunar eclipses and partial lunar eclipses are both umbral lunar eclipses. During a total lunar eclipse, the moon is not completely invisible. This is because sunlight is refracted into the umbra when passing through the earth's thin atmosphere and is projected onto the moon, giving the moon a reddish copper color. Depending on the Moon's path through the umbra and the Earth's atmospheric conditions at the time, the brightness will vary during different total lunar eclipses. Sometimes the moon does not enter the umbra but only enters the penumbral shadow. This is called a penumbral lunar eclipse.

During a penumbral lunar eclipse, the moon will be slightly dimmer, but its edges will not be obscured by the Earth's shadow.

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On the 15th and 16th days of the lunar calendar, the moon moves in the direction opposite to the sun. At this time, if the centers of the Earth and the Moon are roughly in the same straight line, the Moon will enter the Earth's umbra, resulting in a total lunar eclipse. If only part of the moon enters the Earth's umbra, a partial lunar eclipse occurs. When the moon enters the penumbra of the earth, it should be a penumbral eclipse, but because its brightness weakens very little and is not easy to detect, it is not called a lunar eclipse. Therefore, there are only two types of lunar eclipses: total lunar eclipse and partial lunar eclipse. Lunar eclipses all occur in Wang (full moon), but not every moon has a lunar eclipse. This is the same as a solar eclipse in every moon. The moon is completely or partially obscured by the Earth's shadow. Lunar eclipses generally occur on the lunar calendar, that is, on the 15th or 16th day of each month in the lunar calendar. At this time, the earth moves between the sun and the moon, but not every lunar eclipse may occur because there is a gap between the ecliptic and the ecliptic. There is an angle of intersection, so observers on the earth can only watch the lunar eclipse when the moon is eclipsed again on consecutive photos of the night and the shadow of the earth is visible near the intersection of the ecliptic and the ecliptic. The number of lunar eclipses that occur each year is generally two. The diameter of the sun is much larger than that of the earth, and the earth's shadow can be divided into the umbra and the penumbra. The diameter of the Earth is about 4 times that of the Moon. At the lunar orbit, the diameter of the Earth's umbra is still equivalent to 2.5 times that of the Moon. A partial lunar eclipse occurs when only part of the Moon is always obscured by the Earth's umbra. A total lunar eclipse can be seen when the moon completely enters the Earth's umbral shadow. If the moon enters the penumbral area, the sun's light can also be blocked. This phenomenon is called a penumbral lunar eclipse in astronomy. However, because the sunlight is still very strong in the penumbral area, penumbral lunar eclipses are not easy in most cases. It can be distinguished with the naked eye, but in fact penumbral lunar eclipses occur frequently. According to observation data, the percentages of penumbral lunar eclipses, partial lunar eclipses, and total lunar eclipses in each century are about 36.60%, 34.46%, and 28.94%.