Question

What are some problems with refracting telescopes?

Answer 1

I know of two:

Explanation:

1) refracting telescopes use lenses that are subjected to aberrations such as chromatic aberration that can cause different colors to focus at different points giving a blurred image;
2) a lens can only be manufactured with limited radius due to the difficulty in making it and defornations that a big lens would have (bending under its own weight); so the lens is bound to have a relatively small diameter and, as a consequence, to collect little light (light for a telescope means infornation about the object; the more light the better!).