Question

Which of these statements best explains why the size of the refracting telescope lens is kept small at the cost of reducing its capacity to gather radiations from space?

Answer 1

You might think it's the cost of grinding a huge lens, but I think actually it's the problem of supporting a gigantic lens without its own weight distorting it. You could easily make giant refractors if you put them in orbit, I think. Another relevant factor for modern astronomy is that you can easily build a reflector for UV or IR light, but it is harder to find substances that are transparent in those areas of the spectrum, from which you could make lenses.