Why can't I see Wei Zi's three yuan?

The area is relatively wide. These three walls include the upper wall, Taiwei wall, middle wall, Wei Zi wall, lower wall and Shi Tian wall. It is not easy for human eyes to observe them, so they can be observed with a magnifying glass. Because the scope is too wide, we can't see three constant pictures of Wei Zi. As star officials, the names of Zi Weiyuan and Tian Shiyuan first appeared in the Star Classic of Kaiyuan, and the name of Tai Weiyuan did not appear until Xuanxiang Poetry in the early Tang Dynasty.