Astrophysics (Index)About

optical axis

(center line through an optical instrument)

The optical axis of a telescope or other optical instrument is the line along which a ray of light is not refracted by a lens, and if reflected by any curved mirror, is reflected at its center-of-curvature. In a telescope that is axisymmetric, the line is the axis of symmetry, through the middle. In the case of reflector telescopes, often the optical axis is not actually used optically, being blocked by the secondary mirror or whatever is located at the prime focus. The optical axis is of use in geometrical descriptions of the instrument's/telescope's optics.


(telescopes,optics,instruments)
Further reading:
https://en.wikipedia.org/wiki/Optical_axis
https://socratic.org/questions/what-is-the-optical-axis
https://www.photonics.com/EDU/optical_axis_OA/d5755
https://www.photokonnexion.com/definition-optical-axis/
https://www.britannica.com/technology/optical-axis
https://www.ux1.eiu.edu/~cfadd/1160/Ch24ML/CrvMr.html
http://boson.physics.sc.edu/~rjones/phys153/raytrace.html

Referenced by pages:
astigmatism
Cassegrain reflector
focal length
focal plane
focal plane tilt
Gregorian telescope
off-axis telescope
spherical aberration

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