Question

what's the center of sky

Answer 1

In a word, no. The universe began as a singularity (an infinitely tiny point with infinite density) that started expanding at the moment of the Big Bang. However, the Big Bang wasn’t a normal explosion starting from a single point in space. Rather, space itself was expanding, with everything in the universe moving away from everything else. Today we observe a universe that appears fairly isotropic; that is to say, it looks basically the same in every direction. In general, the galaxies along any line of sight from Earth are distributed in the same way. There is no “preferred” direction in the universe, which indicates that there is no inherent center of the universe.
hope this will help u understand that there is no centre of sky

Answer 2

It's very complicated one to tell. Scientists are also unanswered for this question.