The resolving power of a telescope refers to its ability to distinguish between two objects that are close together in the sky. It defines the smallest angular separation between two objects that can still be seen as distinct by the telescope. In other words, it’s the telescope’s ability to resolve fine details or distinguish objects that are very close to each other.
The resolving power is often described in terms of angular resolution, which is typically given in arcseconds. A smaller value indicates better resolving power.