One hour of right ascension is equivalent to 15 degrees of sky rotation.

Here's why:

* Earth's Rotation: The Earth rotates on its axis once every 24 hours.

* 360 Degrees: A full circle is 360 degrees.

* Division: Therefore, the Earth rotates 360 degrees / 24 hours = 15 degrees per hour.

This rotation is what causes the apparent movement of stars across the sky, and right ascension is a system for measuring their positions based on this movement.