About this 3D model

The Observing Instrument was an instrument invented by Guo Shoujing, an astronomer during the Yuan dynasty, to measure the sun's declination and hour angle, and could also be used to observe solar eclipses. Its body was made of bronze and resembled a large pot. Astronomers in the Joseon Dynasty of Korea learned from Guo Shoujing's design and simplified it into a spherical sundial called the Observing Instrument Sundial, 앙부일구 (angbuilgu) . This model can measure declination and hour angle, but it cannot observe solar eclipses due to the model's size limitations. The model needs to be adjusted in the following steps before it can be used: 1. Adjust the angle of the y-axis of the latitude and longitude grid according to the latitude (for example, the latitude of Beijing is about 39°N): 2. Cut off any excess part above 86 mm: Assembly of the model requires 4 M2*10 screws. If you do not have them, you can use glue instead.