[Astronomy]
In the vast sky, the stars are crossing, the Dipper is turning, and the Planets are traveling along their orbits day and night. The highlight of the beautiful arc of the orbit is Apsis, of which the charming will last forever.

[Architecture]
In the top center of an arch there is a keystone. It stands pressure from both sides silently but contributes to the completion of the arch of splendor and brilliance. Apsis is the position of the keystone and is shining with wisdom.