{"id":30829,"date":"2022-04-04T09:44:42","date_gmt":"2022-04-04T09:44:42","guid":{"rendered":"https:\/\/www.skyatnightmagazine.com\/?p=45980"},"modified":"2022-04-04T09:54:16","modified_gmt":"2022-04-04T09:54:16","slug":"the-best-outdoor-lighting-to-minimise-light-pollution","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/rss_feed\/the-best-outdoor-lighting-to-minimise-light-pollution\/","title":{"rendered":"The best outdoor lighting to minimise light pollution"},"content":{"rendered":"

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By Allan Howard\n \t\t<\/p>

Published: Monday, 04 April 2022 at 12:00 am<\/p>

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A<\/span>rtificial light can be a nuisance for many people, particularly astronomers. Bright lights at night cause glare discomfort, disability and loss of darkness, all of which creates problems for anyone who wants to admire the splendour of a clear night sky.<\/span><\/p>\n

And \u2018obtrusive light\u2019 isn\u2019t just a nuisance for those at the eyepiece who\u2019d like to be able to observe more stars; it can also have negative economic and ecological effects.<\/span><\/p>\n

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Image: Getty Images \/ iStock \/ AmArtPhotography<\/span><\/figcaption><\/div>\n

The obstructive glow from artificial lights is known generally as light pollution<\/a>, and it comes in different forms:<\/p>\n

Sky-glow<\/strong> is the general, diffuse sheen visible in the direction of large cities, airports and industrial complexes.\u00a0It occurs from both natural and artificial light sources and does not depend exclusively on lighting design, but also on atmospheric conditions.<\/p>\n

Glare<\/strong> is the name we give to the uncomfortable brightness of a light source when viewed against a darker background.<\/p>\n

Light can be propagated into the atmosphere either directly upward or from incompletely shielded sources.<\/p>\n

It may also be reflected off the ground or other surfaces, partially scattering back towards observers and limiting the perceived darkness around them.<\/p>\n

But lighting at night also has its uses, providing visibility and security around your home.<\/p>\n

Luckily, there are lights designed for domestic use that will keep your property safe and won\u2019t impact too much on your nightly observing.<\/p>\n

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Modifying the position of a light source can diminish its polluting effects on the night sky. Credit: BBC Sky at Night Magazine<\/span><\/figcaption><\/div>\n

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The science of light pollution<\/strong><\/h2>\n

When observing the night sky, the human eye becomes nearly or completely dark-adapted, or \u2018scotopic\u2019. The scotopic eye is much more sensitive to blue and green light and much less sensitive to yellow and red light than the daytime-adapted, or \u2018photopic\u2019, eye.<\/p>\n

Different light sources have different levels of apparent brightness to the dark-adapted eye.<\/p>\n

White light sources such as metal halide, fluorescent or white LED can produce up to three times the visual sky glow brightness of a high-pressure sodium lamp.<\/p>\n

Astronomers tend to use a red light source to view star charts, books and notepads in the dark, as this helps to protect night vision adaption.<\/p>\n

Information printed in white text on black paper also helps maintain dark-adapted vision, because the light reflected back into the eye is considerably reduced.<\/p>\n

Below we reveal four types of lighting that can be used for security and safety around the home and garden, including some examples of astro-friendly units that will preserve the darkness.<\/p>\n

Best security lights to minimise light pollution<\/strong><\/h2>\n
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A poorly positioned security light can lead to uncomfortable levels of glare. Credit: iStock<\/span><\/figcaption><\/div>\n

Domestic security lights should provide the minimum level of illumination to light a single property, not half the street.<\/p>\n

Because of the price and ease of installation, many people install tungsten halogen floodlights, which can provide satisfactory security lighting. It is rarely necessary to use a lamp greater than 2,000 lumens (150W).<\/p>\n

These lights can be fitted with detectors to sense the movement of intruders, but often the systems require the detector and the floodlight to be aimed in the same direction.<\/p>\n

Suggested security lights:<\/strong><\/h2>\n

Blooma Pietas external security floodlight<\/strong><\/h3>\n
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