The points on the celestial sphere that are directly overhead at Earth's poles are called the celestial poles. There are two of them:

* North Celestial Pole: This point is directly above the Earth's North Pole.

* South Celestial Pole: This point is directly above the Earth's South Pole.

These points are important because:

* Stars appear to rotate around them: Due to Earth's rotation, stars appear to circle around these celestial poles. This is why Polaris, the North Star, is so important for navigation – it remains almost stationary in the sky for observers in the Northern Hemisphere.

* They define the celestial equator: The celestial equator is an imaginary circle on the celestial sphere that is directly above the Earth's equator. It is 90 degrees away from both the North and South Celestial Poles.

Let me know if you'd like more information about celestial coordinates or the celestial sphere!