aperture

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aperture

Physics
a. a usually circular and often variable opening in an optical instrument or device that controls the quantity of radiation entering or leaving it
b. the diameter of such an opening

aperture

The diameter of the unobscured portion of the objective lens in a refracting telescope or of the primary mirror in a reflector. In a radio telescope it is the physical size of the antenna. As the aperture is increased, the telescope gathers more light, radio waves, etc., and thus will discern fainter objects: the radiation-gathering power depends on area, i.e. on the square of the aperture. A larger aperture also produces a smaller Airy disk and so has greater spatial resolution.

Aperture

An opening for the purpose of admitting light.

aperture

[′ap·ə‚chər]
(electronics)
An opening through which electrons, light, radio waves, or other radiation can pass.
(graphic arts)
A rectangular cutout on an aperture card.
(optics)
The diameter of the objective of a telescope or other optical instrument, usually expressed in inches, but sometimes as the angle between lines from the principal focus to opposite ends of a diameter of the objective.

aperture

(1) An orifice. It often refers to an opening in which light is allowed to pass in optical systems such as cameras and lasers. See f-stop and numerical aperture.

(2) (Aperture) A photo editing and management application for the Mac from Apple. Introduced in 2005 and used by professional photographers, Aperture provides sophisticated touch-up tools and works with the iPhoto library. See iLife.
References in classic literature ?
You're mussing up the floor something awful, you." This last to the dead Wieroo as he stooped and dragged the corpse to the central shaft, where he raised it to the aperture and let it slip into the tube.
The aperture of the rock had been closed with stones, then this stucco had been applied, and painted to imitate granite.
For a moment they breathed more freely, but presently they discovered that the aperture was continuing to enlarge.
That was, in fact, a marvellous grimace which was beaming at that moment through the aperture in the rose window.
Swinging myself in, I found it was the aperture of a narrow horizontal tunnel in which I could lie down and rest.
Above him, through the aperture, Werper could see sunlight glancing from massive columns, which were twined about by clinging vines.
The clear apertures and NA of the 2400B-405 and 2400B-505 match the diameters and numerical aperture of typical liquid light guides.
Bolt sleeve apertures by Belding-Mull and Marble-Goss equipped G&H and Sedgely sporters.
Smaller apertures on the other hand allows the camera to capture sharper images on well-lit environments.
Most mobile cameras, however, have always used fixed focal length lenses with fixed apertures, achieving digital zoom by cropping into the sensor area and reducing image resolution and quality.