Question

why there is a slight shift in the position of star in sky.

Answer 1

due to refraction .

Answer 2

Hi there!

There is a slight shift in the position of star in sky due to Atmospheric Refraction.

As the light from a star enters the Earth's atmosphere, it undergoes refraction and bends toward e normal each time.

The upper layer of the Atmosphere are rarer thanthe lower layers.

Therefore,
The apparent position of the star is slightly different from its Actual Position.

The star appears slightly higher (above) than its Actual position, when viewed near the Horizon.

Cheers!