What's the use of being Ursa minor?

What stars does Ursa minor consist of?

Alpha Ursa minor

China was called "Gouchen No.1" or "Beichen" in ancient times, which belongs to Ziweiyuan among the three walls and is the first of the six stars in Gouchen. Polaris, one of the main bright stars in the northern sky, is located at right ascension 2h3 1m48.7 1s and declination 89 5' 50.6 ". Alpha Ursa is a famous "North Star" because it is the closest to the North Pole among all bright stars. Polaris is also a variable star, with visual magnitude 1.95-2.04. It is also a triad star, about 400 light years away from us. The position of the earth's rotation axis in the sky is very stable, so people define the direction of the earth's rotation axis in the sky as south and north. Polaris is just in the direction of the earth's rotation axis, so in ancient times, when people sailed in the sea and trudged in deserts, forests and wilderness, they always turned to it to indicate the direction. People worship it so much that China even regarded it as a symbol of ancient emperors. It is in today's highly developed science and technology that Polaris is of great significance in astronomical observation, aerospace, navigation, geography and many other scientific and technological fields because of its special positioning function. In any place in the northern hemisphere, you can directly use Polaris to find the north direction. In fact, Polaris is not completely in the North Pole, and it is still 1 away from the North Pole, which has little influence on positioning. No other star is closer to the North Pole than it is, so it is regarded as the North Pole by people nearby. If you stand at the north pole of the earth, the Polaris is directly above you. In other parts of the northern hemisphere, people see that Polaris is always in that position due north. Moreover, due to the rotation and revolution of the earth, the constellations in the northern sky seem to revolve around the North Star every day and every year. In particular, the spoon mouth points to the big dipper of Polaris, and it never tires and never stops. The ancients in China were deeply touched by this. They wrote in the Book of Changes, "Heaven is healthy, and gentlemen are constantly striving for self-improvement. "If it makes sense. Shu Tian (Alpha Ursa Major) and Tian Xuan (Beta Ursa Major) are two stars in the mouth of the Big Dipper Ursa Major. They lead a straight line to the north and extend to the other side five times away from them. One star is either very bright or the famous Polaris. In addition, you can also find Polaris from Cassiopeia: first find the midpoint of ε star (Doug II) and γ star (Ce) in Cassiopeia, and then connect the δ star (Doug III) in Cassiopeia with this midpoint and extend northward, or you can find Polaris.

Beta Ursa minor

In ancient times, China was called "Arctic II" or "Emperor", belonging to the second of five stars in the three walls of the Arctic. A main bright star in the northern sky is located at right ascension 14h50m42.37s, with a declination of 74 9'19.7 "and a visual magnitude of 2.2. Both the beta star (Emperor) and the gamma star (Prince) in Ursa minor are located at the mouth of Little Beidou in Ursa minor, so they are collectively called "polar protection stars". The γ-star Ursa minor, known as "Arctic No.1" or "Prince" in ancient China, belongs to the purple element in the three walls and is the first of the five stars in the Arctic. A main bright star in the northern sky is located at right ascension 15h20m43.73s, declination 7150' 2.5 ",and the visual magnitude is 2.2. The γ star (Prince) and β star (Emperor) in Ursa Major are both located at the mouth of Little Beidou in Ursa Major, so they are collectively called "polar-protecting stars".