how is resolution affected by the size of a telescopes mirror or lens?

And What are some reasons for using mirrors rather than lenses in telescopes?

Well, …, The larger the aperture the more you can see. They the following quick and easy experiment:

Close your left eye, form a very small "OK" with your right hand and look through the center hole will your right eye. Take a mental note of everything you can see. Now open the "OK" and look again. You’ll immediately be able to see more. The ability to gather light, NOT MAGNIFICATION, enables you to see more. Thus a 6" refractor can see much much more at lower power than an 80mm (3.1 in) refractor.

We use mirrors more commonly because:
1) Large mirrors are much easier to make
2) There’s a limit to the about of glass that can go into a lens before light can no longer pass through the lens of the lens becomes so large that it breaks from its own weight.
3) It’s much easier to remove chromatic distortion from a mirror than a lense.
4) Mirrors are cheaper to make.


Comments

how is resolution affected by the size of a telescopes mirror or lens? — 2 Comments

  1. Bigger mirror or lens means better resolution. Scopes with mirrors up to 10 meters have been built, and a 30 meter one is planned.
    Mirrors cost less to produce install in a telescope, and control. In large size, they are supported equally from the back side. A lens bigger than 1 meter or 40 inches sags under its own weight, distorting the image. Lenses have to be corrected for color errors, while mirrors reflect all colors equally. Thick lenses may absorb light, need coatings to prevent ghosts. Mirrors only need good reflective coatings, which can be restored in a vacuum chamber after cleaning.
    References :
    Fifty-one years of building and using telescopes of many types and sizes

  2. Well, …, The larger the aperture the more you can see. They the following quick and easy experiment:

    Close your left eye, form a very small "OK" with your right hand and look through the center hole will your right eye. Take a mental note of everything you can see. Now open the "OK" and look again. You’ll immediately be able to see more. The ability to gather light, NOT MAGNIFICATION, enables you to see more. Thus a 6" refractor can see much much more at lower power than an 80mm (3.1 in) refractor.

    We use mirrors more commonly because:
    1) Large mirrors are much easier to make
    2) There’s a limit to the about of glass that can go into a lens before light can no longer pass through the lens of the lens becomes so large that it breaks from its own weight.
    3) It’s much easier to remove chromatic distortion from a mirror than a lense.
    4) Mirrors are cheaper to make.
    References :

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