Red dot sight

Introduction

Red dot sight is a reflector sight with no magnification.

Collimator sight.

Invented by Howard Grubb.

Theory

Aiming using red dot sight

Spherical partially reflecting mirror.

Parallax free only at infinity, see

Optical system can be made to compensate for off axis spherical aberration.

the Grubb’s reflector

References

https://en.wikipedia.org/wiki/Red_dot_sight

https://www.chuckhawks.com/optical_sights.htm