aperture

(redirected from apertural)
Also found in: Dictionary, Thesaurus, Medical, Legal.

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 ?
Also, it is geometrically feasible for apertural inclinations to approach [+ or -] 90 [degrees], but the observed upper and lower bounds were between +70 [degrees] ([approximately]1.22 radians) and -20 [degrees] ([approximately]-0.35 radians).
the apertural dentition is more complex and the umbilicus is retained and lined with callus.
The apertural end of the muscle grades into the foot (Voltzow, 1990; Thompson et al., 1998), so the only point that could be consistently identified at the apertural end of the columellar muscle was the point at which the muscle attachment began (ATT in Fig.
We prepared the shells as described above, then measured three shell variables: maximum shell length, maximum shell width, and maximum apertural lip thickness with calipers to the nearest 0.01 mm, prior to crushing.
Southeast African specimens develop mature apertural features at a smaller size than those from the north-western Indian Ocean and Red Sea, and never attain such a large size (largest southern African specimen, length 9.6 mm).
Aperture shape, the degree of elongation of the aperture, is analogous to his "shape of the generating curve" but was measured in the apertural plane (Fig.
Recently a number of similar specimens has been collected in the northern Drakensberg escarpment (see above) exhibiting considerable variation in size, shape, sculpture and apertural dentition.
The possible link between pollinators and sexine ornamentation, habitat and apertural configuration, and flower morphology and pollen size also provide exciting research topics in several groups of Rubiaceae.
stn--station; h--height, w--greater diameter (both measured in standard, apertural view).
Shell height and diameter measurements were made with the shell held in apertural view with the axis of coiling vertical, as shown in Fig.