spherical aberration

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Related to spherical aberration: coma aberration

spherical aberration:

see aberrationaberration,
in optics, condition that causes a blurring and loss of clearness in the images produced by lenses or mirrors. Of the many types of aberration, the two most significant to the lens maker are spherical and chromatic.
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, in optics.
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Spherical aberration in convex lensclick for a larger image
Spherical aberration in convex lens

spherical aberration

(sfe -ră-kăl) (SA) An aberration of a spherical lens or mirror in which light rays converge not to a single point but to a series of points whose distances from the lens or mirror decrease as the light rays fall nearer the periphery of the optical element (see illustration). It is most obvious with elements of large diameter. It can be considerably reduced by using an aplanatic system, which also reduces coma, or by using a correcting plate. Paraboloid surfaces are free of spherical aberration, but not of coma. See also Schmidt telescope.

Collins Dictionary of Astronomy © Market House Books Ltd, 2006
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Spherical Aberration


a type of aberration of optical systems. In spherical aberration, rays of light that pass through an axisymmetric optical system, such as a lens, at different distances from the system’s optical axis are not brought to a common focus (Figure 1). Paraxial rays passing through the central zone h0h1 of the system come to a focus in the Gaussian image plane Oh. Rays passing through other zones, such as h1h2 and h2h3, are focused closer than the Gaussian plane in the case of converging, or positive, systems and farther away than the Gaussian plane in the case of diverging, or negative, systems.

As a result of spherical aberration, the image produced by parallel object rays on a screen perpendicular to the axis at the point O has the form not of a point but of a disk, called the circle of confusion, with a bright core and a fainter halo. When the screen is moved along the optical axis, the size of the circle of confusion

Figura 1. Spherical aberration of a converging, or positive, lens

and the distribution of illuminance in the circle are changed. At a certain position of the screen, the size of the circle of confusion is at a minimum, and we speak of the circle of least confusion. The diameter of the circle of least confusion is approximately one-fourth of that of the circle in the Gaussian plane.

A distinction is made between longitudinal and lateral spherical aberration. The longitudinal spherical aberration is equal to the length of the segment Oδs’ measured from the Gaussian plane to the point where the rim rays—that is, the rays passing through the outer zone at the rim of the optical system (h4h5 in Figure 1)—come to a focus. The lateral spherical aberration is equal to the radius of the circle of confusion Oδz’ in the Gaussian plane; this radius is determined by the rays coming from the outer zone h4h5.

Since for converging lenses Oδs’ < 0 and for diverging lenses Oδs’ > 0, spherical aberration can be almost completely eliminated by using a certain combination of lenses in the optical system. In the case of an individual lens with spherical surfaces, the spherical aberration can be reduced by using surfaces that exhibit an optimum ratio of their radii of curvature. If the refractive index of the material of the lens is 1.5, the spherical aberration is at a minimum when this ratio is 1/6. Spherical aberration can also be reduced by using optical elements with aspherical, for example, parabolic, surfaces.


Tudorovskii, A. N. Teoriia opticheskikh priborov, part 1. Moscow-Leningrad, 1948.
Rusinov, M. M. Tekhnicheskaia optika. Moscow-Leningrad, 1961.
Volosov, D. S. Fotograficheskaia optika. Moscow, 1971.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

spherical aberration

[′sfir·ə·kəl ‚ab·ə′rā·shən]
Aberration arising from the fact that rays which are initially at different distances from the optical axis come to a focus at different distances along the axis when they are reflected from a spherical mirror or refracted by a lens with spherical surfaces.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Hernandez, "Influence of spherical aberration, stimulus spatial frequency, and pupil apodization on subjective refractions," Ophthalmic & Physiological Optics, vol.
There was no significant difference between group 1 and 2 in terms of spherical aberration values recorded before surgery and on the month 1 and 2 after surgery (pgreater than 0.05) (Table-I) (Graph.2).
A number of studies have reported that overnight orthokeratology increases the RMS of higher-order aberrations, especially spherical aberration and coma aberration [8, 28, 29].
By controlling levels of spherical aberration in both bifocal and multifocal contact lenses, the image degradation and visual consequences of lens decentration can be minimised.
Several Hubble scientists describe the telescope's affliction as a classic case of spherical aberration. "This is what you learn about in the first optics course you take in school," Westphal says.
Although promising clinical results, in terms of safety, stability, predictability, and efficacy [1-3], were reported, an increase in the corneal spherical aberration was still found in patients undergoing SMILE procedure [4, 5].
Approximately 3-8% of patients implanted with monofocal IOLs will achieve good near vision (adequate for reading newspaper print) due to pseudoaccommodative effects including pupil miosis and increased depth-of-field; chromatic aberration; monochromatic higher order aberrations such as spherical aberration and coma; corneal multifocality; low myopia and against-the-rule myopic astigmatism.
In other words, contrary to some material on the internet, a misaligned secondary mirror doesn't produce astigmatism, coma, spherical aberration, or a stock market crash.
The parameters analysed included total wavefront error (WFE), total high order aberration (HOA), astigmatism, trefoil, coma, quadrafoil, secondary astigmatism, and spherical aberration. Visual acuity measurements included uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) and were assessed with the early treatment diabetic retinopathy study logarithm of the minimal angle of resolution (LogMAR) charts.
However, Bausch & Lomb Biotrue ONEday and Soflens Daily Disposable could potentially improve definition by reducing the amount of spherical aberration. This relies on the patient having the average amount of spherical aberration, which is not always the case.
The light path from the primary passes through the Mangin's glass and curved surface twice, correcting the primary's inherent spherical aberration. But because it is a lens as well as a mirror, it introduces some color aberration to the system.