Collimation

Glossary

Calibration Frames

updated: 2025-03-14

Definition:

The making of a bundle of light rays parallel.
To adjust the line of sight of (an optical device).
The accurate adjustment of the line of sight of a telescope. readjustment, adjustment, registration - the act of adjusting something to match a standard.

A perfect parabolic mirror will bring parallel beams to a focus at a single point. Conversely, a point source at the focus of a parabolic mirror will produce a beam of collimated light, creating a collimator. Because the source must be small, such an optical system cannot produce much optical power. Spherical mirrors are easier to make than parabolic mirrors and are often used to produce approximately collimated light. Many types of lenses can also produce collimated light from point sources.

"Collimation" refers to all of the optical elements in an instrument being on their designed optical axis. It also refers to the process of adjusting an optical instrument so that all of its elements are on that designed axis (in line and parallel). The unconditional alignment of binoculars is 3-axis collimation, meaning that the two optical axes that provide stereoscopic vision are aligned parallel to the axis of the hinge used to select different interpupillary distance settings. In the context of a telescope, the term refers to the fact that the optical axis of each optical component should be centered and parallel so that collimated light emerges from the eyepiece. Most amateur reflector telescopes need to be recollimated every few years to maintain optimum performance. This can be done by simple visual methods, such as looking down the optical assembly without an eyepiece to make sure the components are aligned, by using a Cheshire eyepiece, or by using a simple laser collimator or autocollimator. Collimation can also be tested using a shear interferometer, which is often used to test the collimation of laser-like sources.

Reference:: Collimated beam - Wikipedia

Origin: Collimated beam - Wikipedia