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 periodicals archive ?
Colpos con membrana apertural granular (granulos de [+ or -] 0,3 [micro]m de diametro), el tectum densamente perforado (perforaciones de 0,1 - 0,2 [micro]m), los muros del reticulo de 0,3 - 0,4 [micro]m de ancho y los lumenes varian entre 0,1 a 1,2 [micro]m de diametro.
Margo formando pliegue apertural de 1 [micron]m, psilado, saliente y ligeramente ondulado.
The cause for radical ultimate chamber expansion along with an increase in apertural size or number (or both) remains difficult to explain.
Lesura recta o sinuosa, ocasionalmente indefinida, indice de area apertural mediana a grande.
Conspicuous apertural teeth, which are expressed most consistently in adults (Crothers 1985), occur only in N.
Shell: Medium to large, depressed-discoidal to planorboid, spire very low with little other than embryonic whorls projecting in apertural view; final part of last adult whorl descending gently prior to aperture; whorls more or less evenly rounded, suture indented; umbilicus very wide, its margin evenly rounded; underside of embryonic whorls clearly visible.
SEM images are displayed in vertical columns, one column per genus, and characterise four views: polar, apertural, equatorial, and fractured sections, sometimes taken from different species in a genus, often from different collections of the same species, in order to document as much variation and/or similarity within groups as possible.
Shell ornamentation, an increase in shell size or thickness, and complex apertural morphology may have evolved in response to changes in the type and strength of predation (Vermeij 1977).
As such, these apertural plications cannot affect the function of the columellar muscle, so I consider Oliva sayana to be without folds.