What type of telescope is used by most astronomers?

Question

Is it the reflecting telescope or the refracting telescope?

please include the source of your information if at all possible, thank you.

Answer 1

Google "Dobsonian Telescope"

Excellent, superb design!

Answer 2

This sounds like a homework question...

In any case - I think you have everything you need in the previous answers - so let's put it together.

Professional astronomers use reflectors!

this is because

(a) the do not suffer from chromatic aberration (the change in focal length with color) that makes refractors less useful;

(b) A lense will sag under gravity and distort, the telescope has to track stars, so the distortion changes over time. This makes is pretty much impossible to build very large lenses.

Reflectors can be supported from the underside, so this problem doesn;t arise. (big telescopes are important for seeing faint objects).

This is now an even bigger issue, because mirrors are designed to be able to be manipulated to compensate for seeing issues.

(c) Reflectors absorb less of the light incident on them and thus are better when looking at faint objects.  

This stuff is all in the intro college astro textbooks (for non-science majors)

Answer 3

Reflecting telescopes are more often used, mainly because

they are easier to build.  A large mirror is easier to make

than a large lens because you only need to grind and polish

one side of a mirror rather than both sides of a lens.  Also, a

mirror reflects the light so if the glass contains flaws or tiny

air bubbles it won't matter, since light won't pass through it.

A mirror is also easier to mount since the back can be un-

polished and it can be set onto its mount rather than be

supported by its circumference the way a lens must be.

Refracting scopes work well, but most of them are fairly

small in diameter and don't gather as much light as larger

ones; virtually all large astronomical research telescopes

are the reflecting type for the reasons stated above.

Answer 4

First response is correct.  Refractors necessarily pass the incoming radiation through glass, which will absorb some of the more interesting spectral information.  And, making a flawless lens some dozens of feet in diameter is completely beyond the reach of present technology.

Answer 5

In addition to all answers,problem of chromatic aberration and spherical aberration are to be taken into account. Lenses have this problem but not for mirrors

Answer 6

Most big telescopes are reflecting telescopes. They are cheaper than the same size refracting telescope and can be made much bigger that it is possible to make a refractor.

Answer 7

The reflecting is far superior to refractors, because refractors have an annoying rainbow ring around just about anything you look at. Reflectors do not have this problem.

Answer 8

Most observatories use reflecting telescopes because it's easier to make big mirrors than it is to make big lenses.

Yerkes Observatory has the world's largest refracting telescope, which has an aperture of 40 inches.  There are now several observatories around the world with mirrors larger then a 200-inch aperture.

The Hubble pace Telescope is a reflector.

Answer 9

reflecting telescopes are most commonly used. they are easy and cheap to build, and in some ways, better than refractors. but personally, i prefer my refractor over my reflector, but thats just me.

Answer 10

Most serious observational studies these days are done with interferometers and radio interferometers.  These are complex multiple telescopes that can be used to resolve very distant objects into meaningful views.

Try the web sites for Palomar Observatory, Keck Observatory, and some of the other large observatories for information about the latest interferometric instruments and studies.