An illuminated reticle rifle scope is a standard optical sight that features an internal light source that illuminates the reticle or cross hairs, thereby making them more visible in low light situations. Illuminated rifle scopes generally fall into two categories: general purpose scopes for hunting or recreational shooting and tactical sights used in self defense, military, and police applications. The light sources that illuminate the reticles of the scopes fall into two categories unique to these separate categories. Hunting and recreational scopes generally use a switchable battery powered light emitting diode (LED) as a light source while tactical sights use passive light gathering fiber optics or radioactive tritium lamps.
Optical sights such as the telescopic sights used by hunters and the tactical sights used by military and police offer several distinct advantages over conventional iron or open sights. The hunter's telescopic sight brings the target in close even at long distances where iron sights would all but totally obscure the target. Tactical sights offer a instant, wide view sight picture that allows fast, instinctive shooting under pressure. Traditional glass sights have, however, always had one fault: the scope's poor light gathering characteristics which see the reticles or aiming point disappear in low visibility conditions. Fortunately the illuminated reticle rifle scope has addressed this problem by allowing users to continue shooting in all ambient light conditions.
Illuminated optical sights adhere to the same fundamental designs as conventional sights with wire or engraved reticles or cross hairs located between magnification and focusing optics. In the case of the illuminated reticle rifle scope, the design deviates with the addition of an independent light source that illuminates the reticle when required. In the case of standard telescopic sights, the light source is switchable and typically consists of a LED situated behind the reticle. The LED is powered by one or more flat, watch type batteries and usually features several illumination power settings suitable for all ambient light conditions. One of the most common problems with these sights, however, is over-illumination where even the lowest power settings “burn out” or illuminate the reticle so brightly that it is impossible to use.
The tactical type of illuminated reticle rifle scope typically features low-to-moderate magnification, large optics, and permanently illuminated, single dot engraved reticles. All of these features make for rapid, instinctive sight/target alignment under duress. These sights generally illuminate the reticle with passive, non-powered light sources such as a fiber optic “light rail.” The light rail is an element that gathers light during daylight and transmits it to the reticle. In low light and darkness, the reticle is illuminated by a tritium lamp which is small glass tube filled with radioactive tritium gas that glows with a soft yet strong light and may last up to 12 years.
Red is the most commonly used color for the illuminated reticle rifle scope because it is the easiest on the eye in low light. Many sights use other colors, though, with green, amber, or yellow light sources being common alternatives. This is particularly true of tritium powered sights which feature a predominance of green light sources.