What does this picture mean?

This is the astrolabe, which is often used for horoscope divination.

The astrolabe, a simple astrolabe in16th century, is an important astronomical instrument used by ancient astronomers, astrologers and navigators for astronomical measurement. It is widely used, including locating and predicting the positions of the sun, the moon, Venus and Mars-related celestial bodies in the universe, determining local time and latitude and longitude, and triangulation.