A sight is an aiming device used to assist in visually aligning ranged weapons, surveying instruments or optical illumination equipments with the intended target. Sights can be a simple set or system of physical markers that have to be aligned together with the target (such as iron sights on firearms), or optical devices that allow the user to see an optically enhanced — often magnified — target image aligned in the same focus with an aiming point (e.g. telescopic sights, reflector sights and holographic sights). There are also sights that actively project an illuminated point of aim (a.k.a. "hot spot") onto the target itself so it can be observed by, such as laser sights and infrared illuminators on some night vision devices.