That is because reflecting telescopes will have a greater magnification in a smaller space. Refracting telescopes that magnify to the same degree as reflecting telescopes would be much larger than...
It is cheaper and easier to create mirrors rather than lenses. Large lenses become difficult to support the larger they become. Additionally, mirrored telescopes fold light waves so that a telescope...
most large optical telescopes are reflectors; light does not pass through a mirror so the glass for reflecting telescope does not have to be of optical quality.