Crux is a group of stars in the sky that looks like a small cross. It is part of an important Chinese system of astronomy.
In Chinese astronomy, the sky is divided into 28 mansions, which are like different neighborhoods in the sky. Each of these mansions has different stars and meanings associated with it. Crux is located in the southern part of the sky, in a mansion called the Red Bird of the South.
Crux is especially important because it can be used to help navigate at night. Long ago, Chinese sailors would use the position of Crux in the sky to help them find their way across the sea. The stars in Crux are also used in astrology to predict events and fortunes.
Overall, Crux is an important part of Chinese astronomy and culture that has been studied and used for thousands of years.