Mars rushes to the sun, and the sun and Mars rise and fall again and again.
Mercury transit principle
The principle of mercury transit is similar to that of solar eclipse. Because mercury and the earth's orbit around the sun are not on the same plane, the inclination angle is 7 degrees. Therefore, only when the orbits of mercury and the earth are on the same plane and the sun, water and the earth are in a straight line can a small black dot on the sun be observed on the earth, which is called the transit of mercury. Small black spots are formed because mercury blocks some of the light from the sun to the earth.
The earth passes through the descending intersection of Mercury orbit around May 8 every year, and passes through the ascending intersection of Mercury orbit around June 1 10 every year. Therefore, the transit of mercury can only occur around these two dates.
Mars provides
Mars provides
When the earth is between Mars and the sun, Mars will cover the sun.
When the difference between Mars and the meridian of the sun is 180 degrees, it is called that Mars rushes to the sun. At this time, Mars and the sun are on both sides of the earth. As soon as the sun goes down, Mars rises in the east, the sun rises in the east and Mars sets in the west, so Mars can be observed all night. Generally speaking, Mars is closer to the Earth during an eclipse, and its brightness is the brightest in a year.
Rushing to the sun refers to an astronomical phenomenon in which an outer planet (Mars, Jupiter, Saturn, Uranus, Neptune and Pluto) runs in a straight line with the earth and the sun during its revolution around the sun, and the earth is just between the sun and the outer planet. Because asteroids also belong to outer planets, there is also a phenomenon of "rushing". The corresponding date of "Chong" is "Chong Ri". If it is closest to the earth at this time, it is called "Daxiong". At this time, the planet is the brightest, visible all night, and most suitable for observation.
Cross star
1, the cross is the North Cross and the South Cross.
Northern cross star
The Northern Cross is Cygnus.
Cygnus is the most easily seen constellation in summer except Scorpio. It can be found in dim band galaxies that appear from June to September. It consists of about nine stars arranged in a huge cross, just like a swan spreading its wings and flying. Just opposite the Southern Cross constellation, also known as the Northern Cross constellation. The Japanese call it Bai Niao. It is right in the middle of the galaxy belt, and a bright white star can be seen at the northeast end, which is the main star of Cygnus-Tianjin. 4. It is the brightest star at 19 in the whole day, which is 1800 light years away from us, and its brightness is more than 60,000 times that of the sun. It is a huge Supergiant star. In its east, there is a nebula shaped like the North American continent. Often called the North American Nebula. In the beak of Cygnus, there is a famous binary star called Tsunami, which can be seen through a small telescope. In addition, in the center of the long neck of Cygnus, there is a blue giant star numbered HDE 226868, and next to it, there is a celestial body named Cygnus X- 1, which is the first suspected black hole to be discovered.
South Cruz
The Southern Cross is a star in the sky, but maybe you have never seen it. This star can only be seen in the southern hemisphere.
The southern cross, which is located due south, is easy to identify. Sailors in the north rely on the Big Dipper and Polaris to judge the true north direction, and when they run to the southern hemisphere, they need to rely on the Southern Cross to judge the true south direction.
Southern Cross, the favorite star, is as bright as a diamond. It is said that as long as you wish on it, your dream will come true.
trait
The main bright stars on the seat: cross I (γ), cross II (α), cross III (β) and cross IV (δ) form a cross. Because there are no bright stars near the south celestial pole, cross I and cross II are used to indicate the direction-only by extending the distance between them by about 4.5 times is the south celestial pole. So this cross is as important in the southern hemisphere as Beidou in the northern hemisphere.
In addition, the intersection of the middle vertical line connecting Nanmenxing Centauri and Marbury I and the above extension line will also be the south celestial pole.
There are two bright stars next to the Southern Cross. They are Alpha and Beta Centauri, and they are the pointers of the Southern Cross. If you find them, you can point out the Southern Cross.
Deep sky object
The coal pocket nebula located in the Milky Way is one of the most striking dark nebulae in the sky, which can be easily seen with the naked eye.
Ngc4755, discovered in 175 1 and 52, is another deep-space object of the Southern Cross. Commonly known as the "jewel box", it is about 7500 light years away from the earth and contains about 100 stars.