Brief introduction of Ursa major

At different latitudes of the earth, the constellations you can see are different. The constellation Ursa major can be seen all year round in areas above 40 north latitude, that is, north of Beijing and Greece. However, in spring, Ursa major is high in the northern sky, which is the best time to watch its panorama in four seasons. Ursa major ranks third in the whole sky, second only to Ophiuchus and Virgo. Because of the existence of the Big Dipper (from Alpha Ursa major to η Ursa major, except for Delta Ursa major, the other six are bright stars above second star), Ursa major is probably the most famous constellation in the whole day. The first two stars of the Big Dipper, α and β, are signs for finding the North Star, and the connection between these two stars directly points to the North Pole.

The second star with spoon handle (ζ Ursa major) is actually a cluster star, and we can see a fourth-class companion star Alcor with naked eyes. Through the small telescope, we can also see another star near Ursa major, which is also a 4-star. In fact, these three stars are each a binary system, so this is a six-star system. Another interesting thing is Ursa major ξ, a binary system consisting of two yellow stars, which have been moving with each other for 60 years. This constellation has two spiral galaxies: M8 1 of 8 and M 10 1 of 9. In ancient China, the seven bright stars in Ursa Major were considered to be in the shape of a spoon, which is what we often call the Big Dipper. The three stars η, ζ and ε are the handle of the spoon, and the four stars α, β, γ and δ constitute the spoon body.

In fact, when looking at the constellation Ursa major, the shape of the spoon is easier to see than the image of the bear. The spoon is in the sky all year round, and the direction of the spoon handle changes in different seasons, just one direction in a season. In the words of the ancients, it is: "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. " . There was no calendar in ancient times, so people used this method to calculate the four seasons. Of course, due to the rotation of the earth, this phenomenon must be seen after eight o'clock in the evening.