How to find the Big Dipper?

Before observing, you need to determine the latitude of your observation site. Because the horizon height of Polaris is equal to the geographical latitude of the observer.

After determining the latitude, when night falls on a sunny day, you face the north, look horizontally, look up, and the angle is just the degree of latitude (if you are at 45 degrees north latitude, you have to raise it by 45 degrees, how to measure this angle, hehe, find a protractor if it is simple).

At this time, there should be a bright star in the center of your field of vision relative to the stars around it. This star is called Alpha Ursa minor, which China traditionally called "Gouchen II". Also known as Polaris.

Extended data

The Big Dipper is a part of Ursa major. Graphically, the Big Dipper is located at the tail of Ursa Major. Six of these seven stars are secondary stars, and 1 is tertiary. Through the connection of the two stars in the mouth of the bucket, it extends about 5 times in the direction of the mouth of the bucket and finds the Polaris.

"Star Recognition Song" has: "Star recognition begins with Beidou, and then begins from north to west." Beginners can look for other constellations in turn from the Big Dipper. The seven stars of Ursa Major are arranged in the shape of a spoon. The ancients attached great importance to Beidou because it can be used to identify the direction and set the season.

Shu Tian, Tian Xuan, Tianji and Tian Quan are the four stars that make up the Big Dipper, and the three stars with handles are Yuheng, Kaiyang and Ursa Major. The star in the center of the handle is called "Kaiyang", and there is a fourth-class companion star called "auxiliary star" at the distance of 1 1. Kaiyang and the auxiliary star form an optical binary star, which can be recognized by naked eyes.

Kaiyang and auxiliary stars are also the only physical binary stars visible to the naked eye all day. The position of the Big Dipper in the night sky is different in different seasons. Therefore, ancient China people determined the four seasons according to its position change.

Among the Big Dipper, "Yuheng" is the brightest, and its brightness is almost close to the first-class star. "Tianquan" is the blackest and is a third-class star. The other five are all second-class stars. There is a small companion star named Fu near Kaiyang, which has always attracted people's attention with its beautiful and clear appearance. It is said that ancient Arabs used it as a "test star" to test soldiers' eyesight when recruiting soldiers.

The Big Dipper always moves slowly in the sky. Five of the stars move in one direction at roughly the same speed, while Shu Tianhe and Yao Guang move in the opposite direction. Therefore, in the long cosmic changes, the shape of the Big Dipper will change greatly. After 654.38+ million years, we will not see this handle shape.

The Big Dipper is also called "Beidou" for short. Not far from the north celestial pole, seven bright stars are arranged in a barrel shape (see photo). All six stars are second-class except delta, which is a third-class star. Polaris can be found by connecting the first two stars of the Big Dipper and extending it to the mouth of the Big Dipper for about five times, which is usually used as a sign to indicate the direction and identify the constellation.

Refer to Baidu Encyclopedia-The Big Dipper