Page:Glossary of NPIC Terminology (1965).pdf/4

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abandoned -- Status of an identified target or component thereof determined from photography to be not in use and unoccupied and not in a condition to be of immediate use. absorber -- An object which readily "soaks up" radiation; a good absorber reflects poorly and is a good emitter. (infrared) absorption coefficient -- A number characterizing the ability of a given material to absorb or attenuate radiations of a specified energy. The linear absorption coefficient expresses this ability per unit thickness and is stated in units of reciprocal length or thickness. The mass absorption coefficient is equal to the linear absorption coefficient divided by the density of the absorbing material; it is a measure of the absorption ability per unit mass. (infrared) access road -- A road branching from the complex main road to provide access to a launch area and/or group. (missile) active -- Status of an identified target or component thereof determined to be currently operating or in use. activity -- Physical manifestation of change indicating a state of action. Frequently used with changes which cannot be given a clear and concise identification such as unidentified military activity, track activity, or construction activity. aerial bomb -- An unpowered, usually free-falling device intended for delivery by aircraft for the purpose of causing damage and/or casualties. air base -- The distance between 2 exposure stations (points in space occupied by the camera lens at the moment of exposure). altitude correction graph' (ACG) -- A graph depicting basic mission parameters for the determination of the scale of certain types of photography. annotation -- Words, phrases, figures, or symbols placed on photographs or drawings for explanatory purposes. Annotations are used to indicate items or areas of special importance. antiballistic—missile (ABM) -- An adjective pertaining to objects or activities for countering ballistic missiles. antimissile missile (AMM) -- A missile designed to intercept and destroy another missile in/flight. apparent radiance -- The radiant power per unit solid angle from a source as witnessed by an airborne detector. The apparent radiance is directly related to tone on infrared imagery. (infrared) area -- l. A particular space or surface, e.g., an area of unidentified construction, an unidentified area. 2. A facility serving a special function and one that may be composed of 2 or more subordinate units called sections or sites, and usually 1 element of a larger facility which may be designated as a complex or center. See. armor-piercing bomb -- A bomb designed for maximum penetration before exploding. It is designed with a strong steel case, reinforced at the nose end, and cleanly streamlined. The explosive charge is small compared with the entire weight. (damage assessment) attenuation -- The reduction in the intensity of radiation on passage through matter where the effect is usually due to absorption and scattering. Reduction of radiation intensity caused by the atmosphere is called atmospheric attenuation. (infrared) autopositive -- Film or paper on which a positive image is made from a positive transparency by direct development. azimuth resolution -- See

berth -- A place for securing a vessel. black body -- A hypothetical object which