The better varieties of these scopes are more complex and will require much more study in the future. They are also very expensive scopes, offering some extraordinary views. At the other end of the refractor spectrum is the department store telescope, that while usable, usually offers the poorest quality in this type of scope. Resolving power is the ability of a telescope to render distinct, individual images of objects that are close together. This might also be called high resolution and it is one of the things that only gets better as aperture increases.
Larger mirrors gather more light and can resolve that light better.
Keep in mind that a poor eyepiece in a large scope will make for poorer viewing and resolving power than a good eyepiece. I hope this was helpful. Next month, I ll get down to the nitty-gritty of eyepiece selection.