A detailed explanation of the hall of the great hero and the empress fairy.

Ursa Major (UMa) is one of the northern constellations, with an area of about 1, 280 square degrees. It is located near Ursa major and Leo minor, opposite Cassiopeia. Suitable for spring observation, it is the constellation of the famous Big Dipper. 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. You see, the three stars η, ζ and ε are the handle of the spoon, and the four stars α, β, γ and δ make up 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. This big spoon is in the sky all year round, and the direction of the handle changes in different seasons, and one season happens to be one direction. 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, we can't see this phenomenon until after 8 pm. Cassiopeia is a constellation comparable to the Big Dipper. There are at least 100 stars visible to the naked eye, but only six or seven are particularly bright. Among them, three second-class stars and two third-class stars form an obvious English capital letter "W", which is the most important symbol to identify Cassiopeia. Cassiopeia can also be found in this way: extend the connection line between the celestial pole of the Big Dipper and the Polaris to the south by about the same length, and you can reach Cassiopeia on the shore of the Milky Way.