Why Do Stars Always Appear To Rise In the East and Set In the West and What Is a Circumpolar Star?

Many of the stars you will see in the night sky follow a path across the sky from horizon to horizon.

Circumpolar stars, however, appear to circle the northern and southern celestial poles without ever rising or setting.

This is because the celestial sphere appears to rotate on the axis between its poles, in fact, it is Earth that is rotating on its axis.

If you draw a circle around the celestial pole in your hemisphere, the North Star in the Northern Hemisphere, at a distance equal to the number of degrees of your latitude, the stars within that circle remain above your celestial horizon all night.

For example, if you are stargazing at 40° latitude, any stars within a 40° radius of the North Star do not rise or set, but are always visible traveling around the celestial pole.