Photonics Dictionary: C

A type of comparator with a telescope equipped with a cross wire mounted on a vertical sliding column. It is used to measure vertical distances on fairly near objects.

In a reflecting telescope, the obstruction of the primary mirror by a secondary mirror which blocks a small amount of the light reflected by the primary mirror and introduces additional diffraction.

Chromatic aberration is an optical phenomenon that occurs when different wavelengths (colors) of light are refracted by a lens or optical system, leading to a failure to focus all colors to the same...

A plane mirror mounted on a polar axis that lies parallel to the plane of the mirror. When the mirror is rotated once in 48 hours, celestial objects can be made to appear stationary and are...