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By using two parabolic cylindric mirrors and one plane mirror, the image of the background is directed around an object, making the object itself invisible - at least from two sides. Invisibility is the state of an object that cannot be seen. An object in this state is said to be invisible (literally, "not visible").
Parabolic reflectors are popular for use in creating optical illusions. These consist of two opposing parabolic mirrors, with an opening in the center of the top mirror. When an object is placed on the bottom mirror, the mirrors create a real image, which is a virtually identical copy of the original that appears in the opening. The quality of ...
In the mathematical theory of reflection groups, the parabolic subgroups are a special kind of subgroup.The precise definition of which subgroups are parabolic depends on context—for example, whether one is discussing general Coxeter groups or complex reflection groups—but in all cases the collection of parabolic subgroups exhibits important good behaviors.
A convex secondary mirror is placed just to the side of the light entering the telescope, and positioned afocally so as to send parallel light on to the tertiary. The concave tertiary mirror is positioned exactly twice as far to the side of the entering beam as was the convex secondary, and its own radius of curvature distant from the secondary.
A concave mirror that is a small segment of a sphere behaves approximately like a parabolic mirror, focusing parallel light to a point midway between the centre and the surface of the sphere. As the affine image of the unit parabola
An illusion transmitter uses two parabolic mirrors to transmit 3-D illusions of an object by use of a camera trained on the first mirror, which then sends video signals to a projector aimed at the second mirror.
An external parabolic or elliptical mirror captures zenithal daylight, and converges it, to let it pass through a narrow opening in the exterior wall. On the inside, two parabolic mirrors widen the beam to around 60°. The floor area next to the conventional window is lit by the window. Anidolic mirror lighting systems can be divided into three ...
In the parabolic superposition compound eye type, seen in arthropods such as mayflies, the parabolic surfaces of the inside of each facet focus light from a reflector to a sensor array. Long-bodied decapod crustaceans such as shrimp , prawns , crayfish and lobsters are alone in having reflecting superposition eyes, which also have a transparent ...