Collimator sight: what it is, how it works, and what it is used for

One of the most convenient optical devices is a red dot sight. It makes aiming much easier and faster, and also improves shooting accuracy. Today, red dot sights are used by military and police officers, as well as hunters, sportsmen, and civilian firearms owners.

In this expert article, we offer a detailed understanding of a red dot sight, its operating principle, and its pros and cons. We will also share the basic rules for choosing a device.

The word 'collimator' comes from the Latin 'collimare' and means 'to direct in a line.' Accordingly, a collimator sight is an optical system that, by shaping a beam of rays and particles, helps reduce scattering and improve aiming accuracy during firing.

It's worth noting that collimators are applicable not only to the design of firearms but also to other applications. For example, such optical systems are used in telescopes and microscopes, in cameras for aligning optical paths and calibrating systems, in nuclear diagnostics, radiotherapy, and other fields.

Now let's figure out why a collimator is needed.

The design of collimator sights allows for the projection of a clear aiming mark in the form of a cross, circle, or dot onto the glass or lens. These devices don't require precise alignment of the front and rear sights, as with classic mechanical sights. With a collimator, you simply need to ensure the aiming mark covers the target, and the shot will go where it points, regardless of the shooter's eye position. This means you can aim with both eyes, identifying and locking on to the target much faster.

In addition, the use of a collimator allows you to quickly learn accurate shooting, for example, at a shooting range, without the need to spend a long time developing the 'front sight-rear sight-eye' system.

Collimators are used in a variety of applications, from game hunting and sport to military tactical missions.

Reflex sights have both pros and cons, which are taken into account when choosing.

If we talk about the pros, among them, it is certainly worth noting:

1. Quick target acquisition and acquisition, which especially improves the effectiveness of shooting at moving targets.
2. The ability to aim with both eyes, which significantly increases the shooter's area coverage, and therefore speeds up their reaction time.
3. There are no strict requirements for head position; more precisely, the shooter does not need to perfectly align their eye with the aiming axis.
4. Learning to use a reflex sight requires mastering a small number of skills.
5. The sight is lightweight and relatively compact, which allows it to be used on short platforms and for mobile shooting.
6. With small changes in the eye, the mark practically does not shift, that is, parallax is minimal.

Reflex sights also have several features:

• Reflex sights don't allow for ballistic compensation, meaning they don't take into account bullet drop, wind, or the height of the sight above the barrel. They only show direction.
• These devices have a zoom function, meaning shooting at very long distances will be ineffective.
• If the shooting distance is too long or the reticle brightness is poorly adjusted, it may obscure target detail.
• The need for regular battery charging or carrying spare batteries for the LED or laser to function. Once the battery runs out, the shooter loses the ability to aim accurately.

To understand how a red dot sight works, you need to know its structure. A sight consists of several elements:

• A housing made of aircraft-grade aluminum or another durable composite material. The housing's main purpose is to protect the electronics and optics from adverse external factors.
• An optical lens, made of translucent, multilayer glass, which displays the reticle. The angle and shape of the lens are adjusted to avoid target distortion and parallax.
• An emitter, typically an LED or laser, which forms the reticle.
• Reticle adjusters (screws), whose purpose is to shift the reticle vertically and horizontally and adjust its brightness.
• Power sources — batteries or built-in rechargeable batteries.
• Mounts — various rails and rails.

Some models are additionally equipped with light sensors and colored aiming reticles.

Now let's delve into the most interesting part—how a collimator sight works and what you can see. When the device is turned on, the power source primes the light element. It projects a reticle onto the translucent glass of the sight, located in the housing on the side or in front of the glass, so that the beam, incident at an angle, is reflected from the lens to the shooter's eye. The reticle's optical design allows the beams to emerge parallel. As a result, the image appears somewhat distant and barely shifts with slight eye movement.

What the shooter sees while aiming

While aiming, the shooter sees a reticle on the glass as a bright dot that appears to be on the target.

However, as we noted above, it should be noted that the collimator only shows the direction, but does not bullet trajectory. The parallax effect is minimal, but not zero, and the device itself has no magnification.

There are several types of collimators, which have been improved and modified over time, and each have their own advantages and features. The following are available on the market:

1. Open or reflex collimator sights. A simple, lightweight device consisting of a translucent lens, a small optical unit, and a light source. The tubular body is absent, which improves visibility. Among the main advantages are light weight and quick target acquisition. Among the features is minimal protection of the optics from external influences (dust, dirt, impacts).
2. Closed or tubular collimators. Equipped with a tubular body, which increases protection and service life of the devices, allowing for active operation in various weather conditions. However, they are heavier and have less field of view, compared to open sights.
3. Holographic sights. A separate type of device, similar to collimators, but with a different operating principle. These models project a reticle not with an LED dot, but using a laser and a holographic plate. They provide a clear image and allow for effective use of the weapon while moving.

Shooting efficiency directly depends on understanding how to choose the right red dot sight. It must be perfectly compatible with your weapon. When choosing, consider the following factors:

• Weapon type. In this case, we are talking about a characteristic called allowable muzzle energy. This indicates the load the sight can withstand without degradation.

Here are some clear guidelines you can use when making your purchase:

For those who plan to alternate or change weapons frequently, the best choice is a universal red dot sight with a high muzzle energy rating and good mounts.

• Case characteristics. The choice of an open or closed case depends on the conditions and purposes of use. Closed collimators are often used for hunting or on sniper platforms, where weather is a factor. Open sights are suitable for pistols, airguns, and carbines, where active shooting is important, which means the weight of the weapon and the field of view.
• Reticle shape and size. The red dot reticle is the most popular among shooters. However, its diameter varies greatly. It is indicated in special units - MOA (minute of angle), less often - in miliradians. 1 MOA is approximately 2.54 cm at 91 m. Therefore, the smaller the reticle, the more convenient it is to aim and Shoot at long ranges. The larger the dot, the easier it is to aim the reticle at the target. For rifles, an adequate dot size is 1–3 MOA, for pistols—4–8 MOA. However, the main factor when choosing is what is more important—speed or accuracy.
• Power source. Modern models are often equipped with CR2032 batteries. Pay attention to the battery life of the scope, which varies from device to device. Another important point is the ease of replacing batteries. We recommend choosing scopes that allow you to change the power source without removing the weapon.
  There are also options with built-in batteries and hybrid devices with a solar panel on the body. There are also models that operate solely on solar energy for a long time without the need for a battery.
• Brightness of the reticle. In high-quality models, the reticle The reticle adjusts well to lighting conditions. This is due to the presence of multi-stage or smooth adjustment. There are automatic, digital, and electromechanical adjustment types.
• Collimator Mount. There are several standard types of sight rails and mounts. These determine both the ease of installation and compatibility with the weapon.
  The main rails include the classic Weaver with grooves approximately 21 mm wide, the Dovetail (8-12 mm wide), and the military-standard Picatinny.
  If the weapon does not have an accessory rail, an additional bracket attached to the receiver is used as a mount. However, this can only be done by a specialist gunsmith.

A red dot sight is an indispensable and reliable optical device for accurate and effective shooting. It is used by hunters, sportsmen, military personnel, and civilians (gun owners). If the red dot sight is chosen correctly, you can significantly increase the accuracy of each shot.