Forward Looking Infra Red (FLIR) systems have become an important addition to the family of surveillance and fire control sensors associated with a variety of military weapon systems. These systems, operating primarily within the 8 to 14 micrometer atmospheric window, provide a real time image of ground, surface or air targets. Since the image results from the thermal contrast differences between targets and backgrounds, no external light source, such as moonlight, is necessary for operation at night. The systems were first used extensively during Southeast Asia operations in the late 1960's, where their main drawbacks were cost, size and weight. These latter problems were addressed over the past 5 years and a common design has evolved which results in compact, affordable systems which meet 80% of known DoD needs.