The armillary sphere was invented by Luo Xiahong, which is the general name of armillary sphere and elephant. The armillary sphere is an instrument for measuring the coordinates of celestial spheres, like an instrument used to demonstrate celestial phenomena in ancient times. Hunyi and Hunxiang are musical instruments that embody Huntian theory.

Huntian theory is an important cosmic theory in ancient China, which holds that "Huntian is like a chicken, celestial bodies are round like an egg ball, and rehmannia is like a chicken". The sky is full of water, supported by air, and the earth floats on the water. Hunyi and Hunxiang are instruments that embody Huntian theory, namely "materialization" and "Huntian theory".

Luo, an astronomer in the Han Dynasty and the Western Han Dynasty, put forward the theory of "Huntian", which innovated the theory of the origin of the universe in ancient China and invented "Tongzhi", and influenced astronomy and mathematics in China in 2000. The calendar he created in cooperation with Deng Ping and Tang Dou is superior to other 17 calendars proposed at the same time.