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The Bortle dark-sky scale (usually referred to as simply the Bortle scale) is a nine-level numeric scale that measures the night sky's brightness of a particular location. It quantifies the astronomical observability of celestial objects and the interference caused by light pollution .
Light pollution is the presence of any unwanted, inappropriate, or excessive artificial lighting. [1] [2] In a descriptive sense, the term light pollution refers to the effects of any poorly implemented lighting sources, during the day or night. Light pollution can be understood not only as a phenomenon resulting from a specific source or kind ...
Laser light interacts with a glass sphere: the radiation pressure force causes it to vibrate. The presence of a single molecule on the sphere disturbs that (thermal) vibration, and the disturbance in the sphere's motion can be detected in the oscillator spectrum on the left. [33]
Predominantly because of this effect, white light sources such as metal halide, fluorescent, or white LED can produce as much as 3.3 times the visual sky glow brightness of the currently most-common high-pressure sodium lamp, and up to eight times the brightness of low-pressure sodium or amber Aluminium gallium indium phosphide LED.
Ecological light pollution [1] is the effect of artificial light on individual organisms and on the structure of ecosystems as a whole.. The effect that artificial light has upon organisms is highly variable, [2] and ranges from beneficial (e.g. increased ability for predator species to observe prey) to immediately fatal (e.g. moths that are attracted to incandescent lanterns and are killed by ...
Figures 1 and 2 in A Preliminary communication on the pressure of heat and light radiation, Phys. Rev. 13, 307-320 (1901).. A Nichols radiometer was the apparatus used by Ernest Fox Nichols and Gordon Ferrie Hull in 1901 for the measurement of radiation pressure.
The current versions has only one band of observation, that can produce misinterpretations if the light pollution changes from sodium-vapor lamp to LED. [ 8 ] The SQM-L, or "Sky Quality Meter - L," is a model with an additional integrated lens, offering a narrower measurement range of 20° compared to the 84° range of the standard SQM model.
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