What does dog sign mean?

Every year on March 2 1, go to Zhongtian at 8 pm. It is connected to Ophiuchus in the north, to Vela in the south, between the tail and the pumping station, and just at the midpoint between Ophiuchus Alpha (Ophiuchus I) and Carina. Part of the constellation is submerged in the Milky Way. The compass is a small constellation composed of a group of rather dark stars. The brightest stars in the constellation are three fourth-order stars. It is really a dark constellation and there is no image. Residents in the area south of 53 north latitude can see the complete compass, while residents in the area north of 73 north latitude can't see the constellation. The compass, the sail, the stern and the base are called "South Four Boats".

The Big Dipper is the most active star among the known circulating nova. Usually it is a dark star, with a brightness of 14. Every 18 to 24 years, the brightness increases by 1000 times (with irregular periodic changes), and the magnitude of dozens of stars increases to 6.5. Compass alpha star (named "Tiangou V" in Chinese), apparent magnitude 3.68, distance 1300 light years. It is a blue-and-white giant of B1.5 Ⅲ Ⅲ type. Compass beta star (named "Tiangou IV" in Chinese, with apparent magnitude of 3.97 and distance of 180 light years) is a * * subgiant. Compass γ (Chinese name "Tiangou Six") is a K3Ⅲ red giant with an apparent magnitude of 4.0 1 and a distance of 99 light years.