optical axis

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optical axis

The imaginary line passing through the midpoint of a lens, mirror, or system of such elements and on which lies the focal point of parallel paraxial rays.
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 It might be outdated or ideologically biased.

Optical Axis

 

The optical axis of a lens or a concave or convex mirror is the straight line that is the axis of symmetry of the refracting surfaces of the lens or of the reflecting surface of the mirror. It passes perpendicularly through the center of these surfaces. Optical surfaces that have such an axis are said to be axially symmetric. The optical axis of an optical system is the common axis of symmetry of all the lenses and mirrors in the system.

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

optical axis

[′äp·tə·kəl ′ak·səs]
(anatomy)
An imaginary straight line passing through the midpoint of the cornea (anterior pole) and the midpoint of the retina (posterior pole).
(optics)
A line passing through a radially symmetrical optical system such that rotation of the system about this line does not alter it in any detectable way.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

optical axis

An imaginary line drawn from the geometric center of a film to the center of a lens. It may project beyond the lens. Also called a lens axis and a camera axis
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved
References in periodicals archive ?
Any deviation in the course of the seeker control loop will make the body attitude angle couple into the LOS rate output, because the missile will be subject to airflow, disturbance torque in the flight process, thereby affecting the stability and tracking of the radar seeker beam axis and reducing the missile guidance accuracy [19-22].
The total displacement at any given point of the section is related to the beam axis displacements as
The calculations are in good agreement with measurements on the neutron beam axis for the 43-MeV p-[sup.7]Li neutron source with up to 25% discrepancy, as shown in Table 2.
All 4 radars are able to capture and describe the "27-day" variability of the microwave signal emitted by the Sun; the DRAO reference curve, which refers to accurate 1-hour-long daily measurements with the antenna radiation pattern beam axis hitting the center of the disk, is obviously much smoother than radar daily estimates, which are retrieved by fitting tens of off-axis hits acquired during a fraction of a second.
The authors developed a program in MATLAB that performs the calculation of (11) and (12) depending on the orientation of the body frame relative to the orbital frame and angle of the ion beam axis deflection a.
Nevertheless, the photon fluence appears to decrease as we move further away from the beam axis, since the thickness decreases with the distance of the axis of the beam due to the geometry of the flattening filter.
TBM constitutes an improvement over EBBM since the cross-section does not necessarily remain perpendicular to the beam axis after deformation and one degree of freedom (i.e., the unknown rotation [[phi].sub.Z]) is added to the original displacement field (see Figure 2(b)).
"In radiography, if a defect's orientation is more than 8[degrees] in relation to the beam axis the defect is unlikely to be detected," says Richards.
A rigid arm is placed between the deviator and the beam axis, while the rubber element, which can adjust the frictional coefficient between external tendon and deviator, is set in the node between the rigid arm and beam axis.
In order to determine the process function HV, hardness was measured in several characteristic points, that is in the points [a.sub.0], b and c located on the beam axis and, respectively, in symmetrical points [a.sub.s1], [a.sub.d1], [a.sub.s2], [a.sub.d2] and [b.sub.s], [b.sub.d], [c.sub.s] and [c.sub.d], represented in figure 1.
For 100% efficiency, detector modules are consecutively placed along the beam axis. Analysis over several regions with alternating wire strip orientation provides a two-dimensional beam profile.
The magnitude and phase of received RF energy each feedhorn receives varies according to the position and vector velocity of the target relative to the beam axis. The received beams include a sum channel, a difference signal between the upper and lower halves of the antenna, and another difference signal between the left and right halves of the antenna.