Why do astronomers use reflecting telescopes rather than refracting telescopes?

Reflecting telescopes consist of a set of curved mirrors used to focus light. With a concave mirror in the back it consentrates the light making the image brighter.

Refracting telescopes is an optical telescope the refracts light at each end using lenses.

So why do astronomers prefer refracting telescopes other than reflecting?
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Refracting telescopes put a very serious limitation on how large the telescope’s aperture can be because they require a large area of unsupported glass. Reflecting telescope mirrors can be supported from behind, so can be built in almost any size. Since aperture is the most important characteristic of modern telescopes, all modern research instruments are reflectors.


Comments

Why do astronomers use reflecting telescopes rather than refracting telescopes? — 3 Comments

  1. Light gathering increases as aperature (diameter of lens or mirror). Astronomers always want more light. A lens bigger than 40 inches has not been used successfully for astronomy. It distorts under its own weight. Mirrors of almost any size (when segments are used) can be made.
    Expense is another factor. Lenses of the same size as a mirror are much more costly to make.
    References :
    Fifty-one years of making and using telescopes of many types up to 25 inch size.

  2. Reflectors can be made larger, cheaper and more easily than refractors.
    References :

  3. Refracting telescopes put a very serious limitation on how large the telescope’s aperture can be because they require a large area of unsupported glass. Reflecting telescope mirrors can be supported from behind, so can be built in almost any size. Since aperture is the most important characteristic of modern telescopes, all modern research instruments are reflectors.
    References :

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