Clouds Illuminated by Light Pollution
Light pollution, also known as photopollution or luminous pollution, is excessive, misdirected, or obtrusive artificial light. .
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Light pollution is a side effect of industrial civilisation. Its sources include building exterior and interior lighting, advertising, commercial properties, offices, factories, streetlights, and illuminated sporting venues. It is most severe in highly industrialized, densely populated areas of North America, Europe, and Japan and in major cities in the Middle East and North Africa like Tehran and Cairo, but even relatively small amounts of light can be noticed and create problems. Since the early 1980s, a global dark-sky movement has emerged, with concerned people campaigning to reduce the amount of light pollution. The International Dark-Sky Association (IDA) is one non-profit advocacy group involved in this movement..
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This form of light pollution is known as Skyglow and refers to the glow effect that can be seen over populated areas such as Basingstoke here. It is the combination of all light reflected from what it has illuminated escaping up into the sky and from all of the badly directed light in that area that also escapes into the sky, being scattered (redirected) by the atmosphere back toward the ground. This scattering is very strongly related to the wavelength of the light when the air is very clear (with very little aerosols). Rayleigh scattering dominates in such clear air, making the sky appear blue in the daytime. When there is significant aerosol (typical of most modern polluted conditions), the scattered light has less dependence on wavelength, making a whiter daytime sky. Because of this Rayleigh effect, and because of the eye's increased sensitivity to white or blue-rich light sources when adapted to very low light levels (see Purkinje effect), white or blue-rich light contributes significantly more to sky-glow than an equal amount of yellow light. Sky glow is of particular irritation to astronomers, because it reduces contrast in the night sky to the extent where it may even become impossible to see any but the brightest stars..
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The Bortle Dark-Sky Scale, originally published in Sky & Telescope magazine, is sometimes used to quantify skyglow and general sky clarity. The nine-class scale rates the darkness of the night sky and the visibility of its phenomena, such as the gegenschein and the zodiacal light (easily masked by skyglow), providing a detailed description of each level on the scale (with Class 1 being the best)..
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Light is particularly problematic for amateur astronomers, whose ability to observe the night sky from their property is likely to be inhibited by any stray light from nearby. Most major optical astronomical observatories are surrounded by zones of strictly enforced restrictions on light emissions..
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Skyglow is made considerably worse when clouds are present. While this has no effect on astronomical observations (which are not possible at visible wavelengths under cloud cover), it is very important in the context of ecological light pollution. Since cloudy nights can be up to ten times brighter than clear nights, any organisms that are affected by sky glow (e.g. zooplankton and fish that visually prey on them) are much more likely to have their ordinary behavior disturbed on cloudy nights..
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This view is from Basingstoke Common in Old Basing, which was provided to replace the original Common in London Road, and was incorporated into War Memorial Park aspart of the new town development. In summer the land is often grazed by cattle, so dogs are recommended to be kept on leads..
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The layered thorn hedges, magpies and rabbits are a familiar sight on the Common. From its highest point the view towards Basingstoke has the distinctive skyline of Festival Place,Basing View and the AA building. The actual town is masked here by higher ground between here and the town..
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Although Basingstoke Common is totally within the parish of Old Basing the common is provided by Basingstoke Council. It is bounded by London Road (A30), Redbridge Lane, Crown Lane and Park Lane. From the A30 end of Park Lane, there are views across to the office towers of Basingstoke. This area, which stretches as far as Basing House is popular with walkers, particularly those with dogs. The common is always considered sacrosanct when developers come looking for land. The fear, though, that one day it will house a new estate is always there..
.
Clouds Illuminated by Light Pollution
Light pollution, also known as photopollution or luminous pollution, is excessive, misdirected, or obtrusive artificial light. .
.
Light pollution is a side effect of industrial civilisation. Its sources include building exterior and interior lighting, advertising, commercial properties, offices, factories, streetlights, and illuminated sporting venues. It is most severe in highly industrialized, densely populated areas of North America, Europe, and Japan and in major cities in the Middle East and North Africa like Tehran and Cairo, but even relatively small amounts of light can be noticed and create problems. Since the early 1980s, a global dark-sky movement has emerged, with concerned people campaigning to reduce the amount of light pollution. The International Dark-Sky Association (IDA) is one non-profit advocacy group involved in this movement..
.
This form of light pollution is known as Skyglow and refers to the glow effect that can be seen over populated areas such as Basingstoke here. It is the combination of all light reflected from what it has illuminated escaping up into the sky and from all of the badly directed light in that area that also escapes into the sky, being scattered (redirected) by the atmosphere back toward the ground. This scattering is very strongly related to the wavelength of the light when the air is very clear (with very little aerosols). Rayleigh scattering dominates in such clear air, making the sky appear blue in the daytime. When there is significant aerosol (typical of most modern polluted conditions), the scattered light has less dependence on wavelength, making a whiter daytime sky. Because of this Rayleigh effect, and because of the eye's increased sensitivity to white or blue-rich light sources when adapted to very low light levels (see Purkinje effect), white or blue-rich light contributes significantly more to sky-glow than an equal amount of yellow light. Sky glow is of particular irritation to astronomers, because it reduces contrast in the night sky to the extent where it may even become impossible to see any but the brightest stars..
.
The Bortle Dark-Sky Scale, originally published in Sky & Telescope magazine, is sometimes used to quantify skyglow and general sky clarity. The nine-class scale rates the darkness of the night sky and the visibility of its phenomena, such as the gegenschein and the zodiacal light (easily masked by skyglow), providing a detailed description of each level on the scale (with Class 1 being the best)..
.
Light is particularly problematic for amateur astronomers, whose ability to observe the night sky from their property is likely to be inhibited by any stray light from nearby. Most major optical astronomical observatories are surrounded by zones of strictly enforced restrictions on light emissions..
.
Skyglow is made considerably worse when clouds are present. While this has no effect on astronomical observations (which are not possible at visible wavelengths under cloud cover), it is very important in the context of ecological light pollution. Since cloudy nights can be up to ten times brighter than clear nights, any organisms that are affected by sky glow (e.g. zooplankton and fish that visually prey on them) are much more likely to have their ordinary behavior disturbed on cloudy nights..
.
This view is from Basingstoke Common in Old Basing, which was provided to replace the original Common in London Road, and was incorporated into War Memorial Park aspart of the new town development. In summer the land is often grazed by cattle, so dogs are recommended to be kept on leads..
.
The layered thorn hedges, magpies and rabbits are a familiar sight on the Common. From its highest point the view towards Basingstoke has the distinctive skyline of Festival Place,Basing View and the AA building. The actual town is masked here by higher ground between here and the town..
.
Although Basingstoke Common is totally within the parish of Old Basing the common is provided by Basingstoke Council. It is bounded by London Road (A30), Redbridge Lane, Crown Lane and Park Lane. From the A30 end of Park Lane, there are views across to the office towers of Basingstoke. This area, which stretches as far as Basing House is popular with walkers, particularly those with dogs. The common is always considered sacrosanct when developers come looking for land. The fear, though, that one day it will house a new estate is always there..
.