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aberration

n. (in optics) a defect in the image formed by an optical device (e.g. a lens). In chromatic aberration the image has coloured fringes as a result of the different extent to ...

aberration

aberration   Quick reference

A Dictionary of Electronics and Electrical Engineering (5 ed.)

Reference type:
Subject Reference
Current Version:
2018

... A defect in the image produced by an optical or electronic lens system. ...

aberration

aberration   Quick reference

World Encyclopedia

Reference type:
Subject Reference
Current Version:
2004
Subject:
Encyclopedias
Length:
63 words

... In astronomy, apparent slight change of position of a star due to the effect of the Earth's orbital motion and the finite velocity of light. A telescope must be inclined by an angle of up to 20° to compensate for aberration. The effect was first described by James Bradley in 1729 and was used to prove that the Earth orbits the...

aberration

aberration   Quick reference

World Encyclopedia

Reference type:
Subject Reference
Current Version:
2004
Subject:
Encyclopedias
Length:
78 words

... In physics, defect in lens and mirror images arising when the incoming light does not fall at or near the centre of the lens or mirror. Spherical aberration occurs when rays falling on the periphery of a lens or mirror are not brought to the same focus as light at the centre; the image is blurred. Chromatic aberration occurs when the wavelengths of dispersed light are not brought to the same focus; the image is falsely...

aberration

aberration n.((in optics))   Quick reference

Concise Medical Dictionary (10 ed.)

Reference type:
Subject Reference
Current Version:
2020
Subject:
Medicine and health, Clinical Medicine
Length:
80 words

... n. (in optics) a defect in the image formed by an optical device (e.g. a lens). In chromatic aberration the image has coloured fringes as a result of the different extent to which light of different colours is refracted. In spherical aberration , the image is blurred because rays from the object come to a focus in slightly different positions: the rays passing through more peripherally are bent more than those passing through centrally. This occurs even with monochromatic...

aberration

aberration n.   Quick reference

A Dictionary of Psychology (4 ed.)

Reference type:
Subject Reference
Current Version:
2015

... n. 1. A deviation from what is normal, usual, or right. See also chromosomal aberration . 2. A temporary lapse of behaviour or mental function. 3. A defect of the crystalline lens of the eye, or of any other lens or mirror, also called astigmatism or dioptric aberration , in which rays of light do not all converge on to a single focal point. In chromatic aberration , different wavelengths of light are refracted through different angles and focused at different distances, leading to blurred images with coloured fringes— see also ...

aberration

aberration   Quick reference

A Dictionary of Physics (8 ed.)

Reference type:
Subject Reference
Current Version:
2019
Subject:
Science and technology, Physics
Length:
218 words
Illustration(s):
1

...aberration 1. (in optics) A defect in the image formed by a lens or curved mirror. In chromatic aberration the image formed by a lens (but not a mirror) has coloured fringes as a result of the different extent to which light of different colours is refracted by glass. It is corrected by using an achromatic lens . In spherical aberration , the rays from the object come to a focus in slightly different positions as a result of the curvature of the lens or mirror. For a mirror receiving light strictly parallel with its axis, this can be corrected by...

aberration

aberration n.   Quick reference

A Dictionary of Nursing (7 ed.)

Reference type:
Subject Reference
Current Version:
2017
Subject:
Medicine and health
Length:
80 words

...aberration [ab-er- ay -shŏn] n. 1. deviation from the normal. 2. a defect in the image formed by an optical device (e.g. a lens). chromatic a. a defect in which the image has coloured fringes as a result of the different extent to which light of different colours is refracted. spherical a. a defect in which the image is blurred because curvature of the lens causes light rays from the object to come to a focus in slightly different positions....

aberration

aberration n.   Reference library

Garner’s Modern English Usage (4 ed.)

Reference type:
Subject Reference
Current Version:
2016

... ; aberrant , n. ; ✳aberrance ; ✳aberrancy . Aberration = (1) a deviation or departure from what is normal or correct; or (2) a mental derangement. Aberrant , which is almost always used in reference to people, means “a deviant; one deviating from an established norm.” ✳Aberrance and ✳aberrancy are needless variants of aberration —enough so to be labeled linguistic aberrations themselves. See spelling (a)...

dioptric aberration

dioptric aberration n.   Quick reference

A Dictionary of Psychology (4 ed.)

Reference type:
Subject Reference
Current Version:
2015

...aberration n. Another name for aberration ( 3 )...

aberration, optical

aberration, optical   Quick reference

A Dictionary of Astronomy (3 ed.)

Reference type:
Subject Reference
Current Version:
2018

..., optical An imperfection or error in the image produced by a lens, mirror, or optical system. There are six types of aberration: chromatic aberration , spherical aberration , coma ( see Coma, Optical ), field curvature , distortion , and astigmatism . Chromatic aberration is not present in images formed by mirrors. All can be corrected to a greater or lesser extent by suitable optical...

diurnal aberration

diurnal aberration   Quick reference

A Dictionary of Astronomy (3 ed.)

Reference type:
Subject Reference
Current Version:
2018

...aberration The aberrational displacement of a star’s position due to the velocity of the observer on the rotating Earth. It is much smaller than annual aberration , amounting to only 0″.3 on the...

planetary aberration

planetary aberration   Quick reference

A Dictionary of Astronomy (3 ed.)

Reference type:
Subject Reference
Current Version:
2018

...aberration The angle between the geometric direction to an object in the Solar System at the instant of observation and its apparent direction as seen by a moving observer. It is the combined effect of aberration due to the observer’s motion and the movement of the planet during the time that its light takes to reach the...

chromatic aberration

chromatic aberration   Quick reference

A Dictionary of Astronomy (3 ed.)

Reference type:
Subject Reference
Current Version:
2018
Subject:
Science and technology, Astronomy and Cosmology
Length:
124 words
Illustration(s):
1

...aberration False colour in a refracting optical system, arising because light of different wavelengths is refracted by different amounts. The most common example is the coloured fringes that appear round images produced by a simple lens. Red light is refracted less than blue light, so the red focus lies farther from a lens than the blue focus. An image which is in focus in yellow light will therefore have a red fringe. The longer the focal ratio of a lens, the less chromatic aberration it will show. Early telescopes were made with very long focal...

spherical aberration

spherical aberration   Quick reference

A Dictionary of Astronomy (3 ed.)

Reference type:
Subject Reference
Current Version:
2018
Subject:
Science and technology, Astronomy and Cosmology
Length:
160 words
Illustration(s):
1

...aberration A defect of mirrors and lenses in which rays of light parallel to but far from the optical axis are brought to a different focus from those close to the axis. Spherical aberration is seen in the images formed by spheroidal mirrors and by some lenses and eyepieces. A star image suffering from spherical aberration has no unique focus but instead has a least circle of confusion where the image is at its smallest. Beyond this point the image is a bright spot surrounded by a disk; inside it, the image is a ring darkening towards the centre. If...

chromosomal aberration

chromosomal aberration   Quick reference

A Dictionary of Genetics (8 ed.)

Reference type:
Subject Reference
Current Version:
2014
Subject:
Science and technology, Life Sciences
Length:
192 words

...aberration any abnormal chromosome complement resulting from an alteration in chromosome structure or number. Chromosomal aberrations can arise spontaneously or be induced experimentally. Intrachromosomal or homosomal aberrations involve changes that occur in but one chromosome. Such aberrations include deficiencies and duplications that result in a reduction or increase in the number of loci borne by the chromosome, respectively. Inversions and shifts involve changes in the arrangement of the loci, but not in their number. ...

chromosomal aberration

chromosomal aberration n.   Quick reference

A Dictionary of Psychology (4 ed.)

Reference type:
Subject Reference
Current Version:
2015

...aberration n. Any visible or gross abnormality in the number or structure of a set of chromosomes . See Klinefelter’s syndrome , trisomy , Turner’s syndrome , XXX syndrome , XYY syndrome . Compare Williams syndrome...

annual aberration

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A Dictionary of Astronomy (3 ed.)

Reference type:
Subject Reference
Current Version:
2018

...aberration The small displacement in position of a star’s image during the year due to the motion of the Earth around the Sun. Annual aberration was discovered by J. Bradley in 1728 from observations of the changes in distance from the zenith of the star Gamma Draconis. The ratio of the Earth’s mean velocity to the speed of light gives the constant of aberration , 20″.5. This is the maximum amount by which a star can appear to be displaced from its mean position. During the course of a year, the star appears to move around its mean position in a...

aberration, stellar

aberration, stellar   Reference library

The Oxford Companion to the History of Modern Science

Reference type:
Subject Reference
Subject:
Science and technology, History of Science
Length:
484 words

..., stellar . Because the observer on the earth is often moving across the path of the incoming light from a star, the observed direction of the star deviates from its true direction. This deviation, known as aberration, depends on the velocity of the observer on the earth and on the velocity of light. The maximum deviation owing to the earth's moving around its orbit is 20.5 seconds of arc. The earth's spin produces an additional much smaller diurnal aberration. James Bradley , England's third Astronomer Royal, discovered stellar aberration...

aberration of starlight

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A Dictionary of Astronomy (3 ed.)

Reference type:
Subject Reference
Current Version:
2018
Subject:
Science and technology, Astronomy and Cosmology
Length:
152 words
Illustration(s):
1

... of starlight The small apparent difference between the observed direction of a star and its true direction ( see diagram ). It is due to the combined effect of the observer’s motion across the path of incoming starlight and the finite velocity of light. The actual amount of displacement and its direction depend on the observer’s speed and direction of motion. Aberration of starlight resulting from the Earth’s orbital motion is termed annual aberration ; the much smaller effect resulting from the Earth’s rotation is diurnal aberration . Planetary...

radiation-induced chromosomal aberration

radiation-induced chromosomal aberration   Quick reference

A Dictionary of Genetics (8 ed.)

Reference type:
Subject Reference
Current Version:
2014
Subject:
Science and technology, Life Sciences
Length:
56 words
Illustration(s):
1

...chromosomal aberration a chromosomal aberration ( q.v. ) induced through breakage caused by ionizing radiation. In the figure below are shown the origin and mitotic behavior of a variety of radiation-induced aberrations. Original break positions are indicated by short diagonal lines. Radiation-induced chromosomal aberration From A. Hollaender, ed., Radiation Biology , Vol. 1 (1954), page 716, McGraw-Hill,...

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