Magnification only matters for optical telescopes.
Resolving power, or resolution. This is the ability to discriminate between two different objects which are very close to each other. For example, suppose there are two lights, one foot apart, and 5000 feet away. Suppose further that when they are viewed through a telescope, they can be seen as two, but if they were any closer to each other, they would appear to be one single object. Therefore the resolving power of that telescope is R .