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How does a refracting optical telescope differ from a reflecting optical telescope?
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Telescope
Aerial view of the Keck Observatory's twin domes, which are opened to reveal the telescopes. Keck II is on the left and Keck I on the right.
Refracting telescopes use lenses to bend, or refract, light to form an image, while reflecting telescopes use mirrors to reflect light to a focus. Reflectors are not subject to chromatic aberration, a distortion where different colors of light do not focus at the same point, which can occur in refractors. Reflecting telescopes also tend to be shorter and less expensive to build than refractors of the same aperture.12