A red dot sight is an optical sight for firearms and smaller astronomical telescopes. In contrast to the rifle scope, a reflex sight offers little or no magnification but is parallax free. The target is captured, unlike the rifle scope, with both eyes.
Due to the construction method, a target can be targeted in the shoulder attack for long weapons both precisely and very quickly over short and (shorter) mean distances . Hits down to lower long distances are possible depending on the extended projectile trajectory.
The red dot sight, unlike a target point projector, does not emit an active beam of light which, in conjunction with the weapon for searching, aiming and quickly detecting at dusk and at night, for accurate shooting from the hip stop by illuminating the target. Red dot sights are also suitable for combat in built-up areas.
A bright target point (or another reticle) is reflected through a semi-transparent mirror in the eye of the shooter. A lens optic (collimator) ensures that this reticle appears closer to the shooter at infinity (or close to a closer target). The shooter sees at the same time through the semitransparent mirror the target and the reticle reflected over the mirror.
Since the light beam of the reticle falls precisely in the direction of the line of sight in the eye, the reticle always appears in the right place regardless of the relative position of the eye to the sighting device.
Basically, three types are distinguished:
- The reticle and the collimator lens are at right angles to the beam path of the object under consideration. The two images are mixed via a beam guide or glass plate. This type requires a lot of space and is mainly used in aircraft head-up displays.
- A more compact style uses a curved dichroic mirror which both focuses the reticle and mixes the two images. This species is often used as a red dot sight on small arms.
- The reticle itself is too close to be in the focus of the viewer, but the curved mirror mixes the two images in the infinity. This species was used as a viewfinder for cameras but also as a weapon sight, for example in the Bazooka.
Among the advantages include the target is sighted with both eyes and the spatial vision as well as the full field of view is preserved. As the target point is imaged into the infinite by means of optics, the eyes can focus the target and the target at the same time. This is not possible with the sight and grain, which are much closer to the shooter so that either the sighting device or the target is always slightly out of focus.
The luminous aiming point makes sighting possible even in the dark, as long as the target is still visible. In order not to be dazzled by the luminous point itself, its brightness can usually be adjusted. Unlike any type of target illumination (such as laser or white-light bulb mounted on the weapon), a red dot sight is also permitted for hunting and sport shooting in accordance with the weapons law.