What are the Big Dipper?

The Big Dipper, also known as the Big Dipper, is seven bright stars arranged in a barrel shape at the tail of Ursa Major. The Big Dipper is named α, β, γ, δ, ε, ζ and η from the top of the bucket to the end of bucket handle. In ancient China, they were called Shu Tian, Tian Xuan, Tianji, Tianquan, Yuheng, Kaiyang and Yaoguang respectively. Shu Tian, Tian Xuan, Celestial Pole and Tianquan are the four stars that make up the Big Dipper. The three stars with handles are Yuheng, Kaiyang and bright and dark binary stars respectively. Through the connection of two stars (α, β) at the mouth of the bucket, walk about 5 times in the direction of the mouth of the bucket and find the North Star. Polaris is usually used as a sign to indicate direction and identify constellations. The position of the Big Dipper in the sky is different in different seasons. Therefore, ancient China people determined the four seasons according to its position change. "bucket handle refers to the east, and the world is spring; Bucket handle guide, the world is summer; Bucket handle refers to the west, and the world is autumn; Bucket handle refers to the north, and it is winter in the world. " . The Big Dipper always makes a slow relative motion in the sky. Five of them move in one direction at roughly the same speed, while Shu Tianhe and Yao Guang move in the opposite direction. With the change of the universe, the shape of the Big Dipper will change greatly. After 654.38+ million years, people may not see the shape of this spoon.