superimposed on the field of view. These sights have been around for over 100 years and have been used on all types of weapons and devices. Reflector sights were first used as a weapon sight in German aircraft towards the end of World War I. Over the years they became more sophisticated, adding lead computing gyroscopes and electronics (the World War II Gyro gunsight) radar range finding and other flight information in the 1950s and 60s, eventually becoming the modern head-up display. Other types of optical sights Collimator sight Holographic weapon sight Laser sight Red dot magnifier used in conjunction with a non-magnified optical sight List of sights There are many types of sighting devices. They can be fixed, mechanical, optical, computational, or a mixture of all of these attributes. Bombsight Collimator sight Diopter sight Globe sight Head-up display Holographic weapon sight Iron sight Laser sight Reflector sight Gyro gunsight Red dot sight Telescopic sight Thermal weapon sight Night vision device Fire-control system See also Gun laying Predicted impact point Tritium radioluminescence Notes External links Firearm components Optical devices Artillery components Surveying instruments es:Visor