샤이별 섀별 셔블 서라벌 신라 경주

천년 문화의 도시,

	This stone astronomical observatory which is regarded as the most important ancient structural artifact in Corea dates back to the three-kingdom period prior to the unification.
	It has 27 levels of stones constructed in a round shape, with four sets of two bars making a square-shaped structure on top of it.

The building, with a strong base of large flat rocks, has a special design.

First, the lower part of it is full of dirt while the upper part is empty. And the stones setting up the wall of the lower part are long. They are fixed firmly by the dirt, which is mixed with very small rocks so that water can go down easily.

Also, long and heavy stones with sharp shape are placed on top of it, which hold the whole structure firm; the heavy weight has helped to keep its original shape.

But some people believe that CheomSeongDae was not an astronomical observatory. The reasons are as follows.

CheomSeongDae is on flat land, not on a mountain. Most modern astronomical observatories are on the top of mountains. This is because most modern cities have electric lights and air pollution, so stars can't be seen well. However, at that time, GyeongJu didn't have any electric lights or air pollution. So the flat land was the best place to build Cheomseongdae.

CheomSeongDae is about nine meters tall. It is not tall enough to see the stars.

What is important to see the stars is to have a wide view. As you see in the picture, the whole sky could be seen. There were no tall building blocking the view.

Cheomseongdae Main

	I derived some of the above pictures and contents from the reference book(Published by 'Didimdol').
	And if there are any claims on them, I will deload them immediately.