Question

Stars appear to be slightlyhigher in sky than they actually are . Why is this so.

Answer 1

Because of refraction in the earth's atmosphere: The air density in the earth's atmosphere and therefore also the index of refraction of the earth's atmosphere decrease with increasing altitude. Snellius' law of refraction tells us that light is refracted towards the medium with higher index of refraction. Therefore, the light coming from any star that is not situated directly above the observer takes a curved path bent down towards the observer, arriving at the observer at a steeper angle than had it travelled on a straight line.

Answer 2

Stars appear to be slightly higher in sky than they actually are because of the refraction of light . Light bends towards the normal or away from the normal depending upon which medium it passes through (rarer or denser).
The observer sees the stars to be higher slightly.
Hope this is helpful!!!