How do we predict solar and lunar eclipses? Pray for the great gods.

A solar eclipse is a typical example of light traveling in a straight line in a celestial body. When the moon moves between the sun and the earth, it is not always like this. When a lunar eclipse occurs, two conditions need to be met. First of all, the solar eclipse always happens on the first day of the lunar calendar. Not all eclipses will happen on the first day of the lunar calendar, because the orbit of the moon (ecliptic) and the orbit of the sun (ecliptic) are not on the same plane. There is an included angle of 59 between the ecliptic plane and the ecliptic plane. On the first day, if both the sun and the moon move near the intersection of the ecliptic and the ecliptic, and the sun and the intersection form a certain angle (eclipse limit), an eclipse will occur, which is the second condition to be met. Because the orbits of the moon and the earth are not perfect circles, and the distance between the sun and the moon is near or far, the shadow formed by the sun being blocked by the moon can be divided into umbra, pseudo-umbra (formed when the moon is far away from the earth) and penumbra on the earth. The observer can see the total solar eclipse in the umbra; Annular eclipse can be seen in the range of pseudoumbra; Only a partial solar eclipse can be seen in the penumbra. There are many mountains on the surface of the moon, and the edge of the moon is irregular. At the moment of the lunar eclipse or the arrival of light, when the valley on the edge of the moon fails to completely cover the sun, the uncovered part forms a luminous area, like a crystal diamond; The reddish aperture around constitutes the "ring" of the diamond ring, which looks like a diamond ring inlaid with bright gems. Sometimes a lot of particularly bright lights or spots are formed, like a string of pearls embedded around the sun. This phenomenon is called Bell Pearl (Belle 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 the solar eclipse can be seen on the earth is also limited, because the moon is relatively small and its umbra is relatively small and short, so the umbra will not sweep the earth for a long time. Because the average length of the umbra of the moon (373,293 kilometers) is shorter than the average distance between the moon and the earth (384,400 kilometers), there are more annular eclipses on the whole earth than total solar eclipses. Knowledge of solar eclipse: At present, the most popular film is Budd film, with a thickness of 0.0 12mm. Visual inspection: 5.0 dimming 10000 times. Photography: During the period of 3.8, the sun will not emit any special rays. Observations of solar eclipses are often misinterpreted. The sun will not predict the occurrence of solar eclipse on the earth, nor will it emit other rays, so it is harmless to stay outdoors during the solar eclipse. But should we stare at or glance at the partial eclipse? Although the sunlight during the eclipse is much weaker than usual, if you look straight, it will still hurt your eyes and possibly your cornea. People stare at or squint at the sun out of curiosity. Of course, the partial solar eclipse is still very dazzling. If you watch the sun for a long time, your cornea will be damaged unconsciously. During the eclipse, the eyes were damaged not because of the abnormality of the sun, but because people were curious and didn't pay attention to protective measures. No matter whether the eclipse occurs or not, don't look directly at the sun with your eyes; Don't use so-called "sunglasses"; Don't use "sunglasses", not even a few folded ones; Don't look at the image of the sun in the mirror or on the water; Looking at the sun with a welding mirror14; Watch it with a specially coated Myra mirror, which can be obtained from the famous planetarium or science museum; Build an aperture projector. How to estimate the eclipse time:: The angle of view of the sun and the moon is about half a degree, and the revolution of the moon is 360 degrees, which means that it moves half a degree every hour, which is the position of one moon, so the eclipse takes at most 2 hours from the beginning to the end, which means moving the positions of two moons, and the time is shorter if it is not a total lunar eclipse. In addition, because the earth is autobiographical, the position of the sun in the sky moves 15 degrees every hour, that is to say, within 30 degrees, the sun and the moon move at the same time and an eclipse occurs at the same time. China solar eclipse in 2009 [1] According to astronomers' prediction, there will be a major astronomical total solar eclipse on the morning of July 22nd this year, and Tongling, Tongcheng and yi county in Anhui Province will be designated as observation points of the National Astronomical Observatory. Yixian Tourism Commission is seizing the opportunity to make a tourism marketing plan, and plans to hold a series of activities of "Painting the Village to Watch the Eclipse" in China in 2009. It is also reported that Yixian County has also been identified by the National Astronomical Observatory as one of the best observation points for simultaneous live broadcast of national media. In 2009, there were two eclipses and three eclipses: 65438+1 October 26th, annular eclipse on February 9th, penumbral eclipse on July 7th, penumbral eclipse on July 22nd and total solar eclipse on August 6th, among which penumbral eclipse1eclipse and two eclipses can be seen in Hong Kong. Details are as follows: 65438+1annular solar eclipse on October 26th (only partial solar eclipse can be seen in Hong Kong). Date and time of solar eclipse: initial loss of 65438+1solar eclipse on October 26th17: 09+1sunset on October 26th18: 04+total solar eclipse on July 22nd (only partial solar eclipse can be seen in Hong Kong). Date and time of solar eclipse The first solar eclipse occurred at 08:00 16 on July 22nd, and it was very severe. The last contact was at 09: 27 on July 22nd, July 22nd 10: 47, and at 0: 00 on February 9th, the penumbral eclipse started at 20: 38 on February 9th and ended at 22:39 10 on February 9th.