Albedo formula_5 (also called blue-sky albedo) can then be given as: Directional-hemispherical reflectance is sometimes referred to as black-sky albedo and bi-hemispherical reflectance as white-sky albedo. These terms are important because they allow the albedo to be calculated for any given illumination conditions from a knowledge of the intrinsic properties of the surface. The albedos of planets, satellites and minor planets such as asteroids can be used to infer much about their properties. The study of albedos, their dependence on wavelength, lighting angle ("phase angle"), and variation in time comprises a major part of the astronomical field of photometry. For small
Javelin (surface-to-air missile) Javelin (surface-to-air missile) Javelin is a British man-portable surface-to-air missile, formerly used by the British Army and Canadian Army. It can be fired from the shoulder, or from a dedicated launcher known as Javelin LML: Lightweight Multiple Launcher. Capable of being vehicle mounted, the LML carries three rounds. It was replaced in front line British service by the Javelin S-15, sold commercially as the Starburst surface-to-air missile in 1993 (radio frequency guided Javelin was retained for some time thereafter for training purposes), and later by the Starstreak starting around 1997. The Javelin GL was hastily purchased by the Canadian Forces