Autokollimátors

An autokollimator is an optical instrument used to measure small angles. It essentially consists of a telescope with a reticle in the focal plane of the objective lens. Light is collimated through the objective, forming a parallel beam. This beam is then reflected off a mirror or other surface. The reflected beam is refocused by the same objective lens, and the image of the reticle is observed through the eyepiece.

When the mirror is perfectly perpendicular to the collimated beam, the reflected image of the reticle is observed in the same position as the original reticle. However, if the mirror is tilted by a small angle, the reflected beam will be deflected by twice that angle. This angular deflection causes the image of the reticle to shift in the eyepiece. The autokollimator is calibrated to translate this shift in the reticle image into a measurement of the angle of tilt.

Autokollimators are used in various applications where precise angle measurement is critical. These include alignment of optical components, testing the flatness and parallelism of surfaces, and in the calibration of angular measuring devices. They are known for their high accuracy and sensitivity to minute angular deviations. The resolution of an autokollimator depends on its magnification and the precision of its reticle and focusing mechanisms. Modern autokollimators can measure angles in the arcsecond range.