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
Cerberus (Martian albedo feature) showing no large craters with diameters 500 m superimposed on Western Cerberus Plains lavas indicate the same surface is younger than 49 Ma. Cerberus (Martian albedo feature) Cerberus is a large "dark spot" (an albedo feature) located on Mars and named after the mythical dog Cerberus. The arcuate markings in the upper right are in the Amazonis plains and may be sand drifts. The Elysium volcano, a yellow area north of Cerberus, has several channels radiating from its flanks. The three bright spots, upper left, are volcanoes partially veiled by thin clouds. High resolution images show the bulk of the