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A concave mirror, or converging mirror, has a reflecting surface that is recessed inward (away from the incident light). Concave mirrors reflect light inward to one focal point. They are used to focus light. Unlike convex mirrors, concave mirrors show different image types depending on the distance between the object and the mirror.
Real images can be produced by concave mirrors and converging lenses, only if the object is placed further away from the mirror/lens than the focal point, and this real image is inverted. As the object approaches the focal point the image approaches infinity, and when the object passes the focal point the image becomes virtual and is not ...
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There are statements about reflected light illumination using a concave mirror, such as: "The first arrangement of this kind was the Lieberkühn mirror from 1738." [ 18 ] In contrast, a book from 1988 states: "J.N. Lieberkühn introduced the concave mirror named after him for reflected light illumination in 1738, as it was used in similar form ...
A concave mirror A convex mirror A convex mirror - SVG version. Reasons of nomination: According to the standards page, the images are: Of High Quality; Have a free license; Add value to an article; Accurate; With good captions; According to the same standards, the images might be: Wikipedia's best work; pleasing to the eye
Foucault test setup to measure a mirror. The Foucault knife-edge test is an optical test to accurately measure the shape of concave curved mirrors. It is commonly used by amateur telescope makers for figuring primary mirrors in reflecting telescopes. It uses a relatively simple, inexpensive apparatus compared to other testing techniques.
Mangin mirrors were used in searchlights, where they produced a nearly true parallel beam. Many Catadioptric telescopes use negative lenses with a reflective coating on the backside that are referred to as “Mangin mirrors”, although they are not single-element objectives like the original Mangin, and some even predate Mangin's invention.
The Mangin mirror was invented in 1874 [1] by a French military engineer named Colonel Alphonse Mangin as a substitute for the more difficult to manufacture parabolic reflecting mirror for use in searchlights. Since the catadioptric design eliminated most of the off-axis aberration found in parabolic mirrors, Mangin mirrors had the added ...