brightness range
31colour — /kul euhr/, n., adj. v.t., v.i. Chiefly Brit. color. Usage. See or1. * * * I Aspect of any object that may be described in terms of hue, brightness, and saturation. It is associated with the visible wavelengths of electromagnetic radiation, which …
32Light pollution — This article is about light pollution in the visible spectrum. For information on pollution in the radio spectrum, see radio spectrum pollution. This time exposure photo of New York City at night shows skyglow, one form of light pollution …
33optics — /op tiks/, n. (used with a sing. v.) the branch of physical science that deals with the properties and phenomena of both visible and invisible light and with vision. [1605 15; < ML optica < Gk optiká, n. use of neut. pl. of OPTIKÓS; see OPTIC,… …
34Cosmic distance ladder — * Light green boxes: Technique applicable to star forming galaxies. * Light blue boxes: Technique applicable to Population II galaxies. * Light Purple boxes: Geometric distance technique. * Light Red box: The planetary nebula luminosity function… …
35Rings of Neptune — The scheme of Neptune s ring moon system. Solid lines denote rings; dashed lines denote orbits of moons. The rings of Neptune consist primarily of five principal rings predicted in 1984 by André Brahic and imaged in 1989 by the Voyager 2… …
36Variable star — A star is classified as variable if its apparent brightness as seen from Earth changes over time, whether the changes are due to variations in the star s actual luminosity, or to variations in the amount of the star s light that is blocked from… …
37Image editing — For the uses, cultural impact, and ethical concerns of image editing, see Photo manipulation. For the process of culling and archiving images, see Digital asset management. A colorized version of originally black and white photo, colorized using… …
38microscope — /muy kreuh skohp /, n. 1. an optical instrument having a magnifying lens or a combination of lenses for inspecting objects too small to be seen or too small to be seen distinctly and in detail by the unaided eye. 2. (cap.) Astron. the… …
39photoreception — photoreceptive, adj. /foh toh ri sep sheuhn/, n. the physiological perception of light. [1905 10; PHOTO + RECEPTION] * * * Biological responses to stimulation by light, most often referring to the mechanism of vision. In one celled organisms such …
40eye, human — ▪ anatomy Introduction specialized sense organ capable of receiving visual images, which are then carried to the brain. Anatomy of the visual apparatus Structures auxiliary to the eye The orbit The eye is protected from mechanical injury… …
