Aiming mark illumination
The presence in the sight of a special
illumination for the aiming mark.
Collimator models, "night lights" and thermal imagers (see "Type") have this function by definition — in fact, the aiming mark itself in them represents either a light mark on the lens (in the first case), or a set of pixels on the screen (in the rest). But for traditional optics, this feature is far from mandatory and is intended mainly for specific cases — for example, when a dark target is on a dark background, which makes the unlit reticle almost invisible. Note that the backlight usually requires a battery to work; there are systems that do not require power (tritium illumination), but they are practically never found in civilian sights.
Backlight brightness adjustments
The ability
to adjust the brightness with which the aiming mark is illuminated.
Such adjustment can be provided in all types of illuminated sights (see above). It allows you to optimally adjust the backlight to the specifics of the situation: for example, if the background in the field of view of the optics is very dark, a too bright grid will “cut the eye” against its background; and for a collimator in bright sunlight, maximum brightness may be required — otherwise the mark will be poorly visible.
Power source
The type of power used in the scope, in fact, describes the type of autonomous element (accumulator or battery) that the device is designed for.
The most popular elements in modern sights are CR2032 elements — characteristic "pills" with a diameter of 20 mm and a thickness of about 3 mm. Their shape fits very well into the layout of both optics and classical collimators (see "Type"), and the capacity, although relatively low, is quite sufficient for normal operation for a long time, because the power consumption of these types of sights is low. But in more “gluttonous” night, thermal imaging (see ibid) and holographic (see above) models, more solid batteries are usually used — most often either a pair of standard “finger” AA cells, or a 3.7 V CR123 element (diameter 17.5 mm, length 35 mm). In this case, the sight can be compatible with either one of these types, or both. It is also worth noting that AA and CR123 elements are also available as rechargeable batteries, which can be perfect for frequent use of the scope.
Sight length
The total length of the sight.
This parameter is important primarily for optical sights (see "Type"). Such devices can be quite large — from
20 – 30 cm in the most compact models up to
40 cm or more ; and the distance from the eyepiece to the eye when aiming must be strictly defined. So before buying, it's ok to clarify whether it will be possible to correctly place the selected model on the weapon. But collimators, even the largest ones, are very compact, usually there are no problems with their installation, so in such models the length does not play a special role.
