Although the methodology of eight-character numerology and astrolabe is different, in the final analysis, they are both "time periods" for studying people and things. There are four seasons on the earth: day and night, human beings are born, old and sick, and everything has its specific periodic changes. Buddhism says that "living in a bad void" is also a cyclical view. But the development of things is extremely complicated, which can not be observed by any intuitive tool. Then, in the accumulation of thousands of years, the ancients used "stars" as a yardstick to calibrate the time periods of various things and characteristics, and even-if the corresponding stars could not be found in the sky, they would invent some "virtual stars" to correspond. These tools and techniques, combined with western astronomical observation, have become the "equal altimeter method" as detailed as 360 degrees today. When it is combined with the Confucian society in the East and the philosophy of Yin-Yang and Five Elements, it becomes a simple eight-character "numerology" with no tricks.