Why do most professional astronomers use reflecting telescopes rather than refracting telescopes?

Question

Why do most professional astronomers use reflecting telescopes rather than refracting telescopes?

Answer 1

for big telescopes, lenses, which are made of glass, are too heavy and almost impossible to handle. They even deform under their own weight when very large

Answer 2

It's the opposite of what you say. Higher contrast without distortion. Refractors are better.

Answer 3

Probably the biggest reason is that reflecting telescopes require one big mirror, and refracting telescopes require one big lens.  The mirror can be supported from the bottom, and only one side needs to be shaped.  But not only does the lens need to be shaped on both sides, but can only be supported from the sides, not the bottom, since light needs to go through - so there's a limit to how big you can make the lenses before they start to sag or there's a good chance they'll break on you.  Mirrors are much easier to make at that size (although it's still pretty tricky).

Answer 4

Greater optical efficiency - more of the incident light comes through the system. It's also easier to make a big mirror than a big lens.

Answer 5

The answers so far cover all the basic reasons. The refractor essentially reached its design limitations about a century ago, and no further development is possible. The reflector is still evolving, which is why all new research telescopes built in the last hundred years have been reflectors.

Answer 6

Mirrors do not suffer from 'chromatic distortion' the

way lenses do.

There are other reasons, but that's the main one.

The other problems could be solved, that one can't be.

Answer 7

bcuz its easier to make big mirrors.

later: chromatic aberration can be corrected - this is why ppl spend big money on apo refractors - but this only makes really big refractors even more unwieldy.

Answer 8

There is an upper limit to how large a refractor can be. Above about 40 inches in diameter, the glass no longer transmits light efficiently. Reflectors do not suffer from this limitation; in theory, they can be any size at all.

Answer 9

One big problem I've had with refractors is that they have that annoying chromatic ring around everything, its hard to deal with. Reflectors don't have this problem. I'm sure that this and expense is why they go for reflectors now.