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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 .
The Bortle scale is a nine-level measuring system used to track how much light pollution there is in the sky. A Bortle scale of four or less is required to see the Milky Way whilst one is "pristine", the darkest possible.
See the Bortle scale.) There is even variation within metropolitan areas. For those who live in the immediate suburbs of New York City, the limiting magnitude might be 4.0. This corresponds to roughly 250 visible stars, or one-tenth of the number that is visible under perfectly dark skies.
A dark-sky preserve (DSP) is an area, usually surrounding a park or observatory, that restricts or reduces light pollution or maintains and protects naturally dark night skies. Different terms have been used to describe these areas as national organizations and governments have worked independently to create programs.
Data showed that Earth's artificially lit outdoor surface at night grew by about 2 percent annually in brightness and area from 2012 to 2016.
Globe at Night is an international scientific research program that crowdsources measurements of light pollution in the night sky. At set time periods within each year, the project asks people to count the number of stars that they can see from their location and report it to the project's website.
Pages in category "Light pollution" The following 27 pages are in this category, out of 27 total. ... Bortle scale; C. Light pollution in China; D. Dark-sky movement;
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. [9]