Star light, Star bright….?

Well maybe, depending on the lighting where you are

Light Pollution

The Problem

Light pollution can affect us more than you may be aware of. Some of the affects include the diminished areas for recreational and scientific astronomy, high-energy consumption, security of property, safety of drivers, health and well being of humans as well as flora and fauna.

Light pollution occurs when too much artificial illumination shines directly or reflected into the sky, this light then reflects off water droplets and dust particles causing a condition called skyglow. Light trespassing is also a problem when light shines past the property line on which the light is mounted, to where it not required or desired.

With dark-adapted eyes, we should be able to see at least 2,600 stars in the sky on any clear moonless evening. In many urban areas and now even many suburban and rural areas have less than 100 stars visible in the night sky. With this lost of viewing for recreational and scientific astronomy we are loosing our shared heritage of the night sky. This is happening form the misunderstanding that more and brighter light translates to greater security and safety.

The energy consumption from lights now concerns to everyone form private, public and corporate institutions. When a bright and ineffective light shines up, sideways as well as down are very wasteful and diminishes safety. No one notices a light that never shuts off, but people notice when a light is switched on.

If lights are too bright then the contrast blocks out seeing anything that might be in the shadows. The glare of bright lights can distract, diminish visual acuity, and temporally blind drivers. Glare can also endanger pedestrians when they can disappear behind the vial of a bright light and cannot be seen by an approaching vehicle.

Bright lights during night can disturb natural circadian rhythms and reduce the levels of melatonin. These harmful effects to health are illustrated by more and more medical studies. Animals are also affected by disturbing bird migration routes and can also be temporarily blinded from bright lights. Bright lights can alter growth rates and change the normal day and night cycle of plants.

The Solution

Energy costs for the owner can be reduced by using less powerful lights that focus light where it is needed, and using a more efferent light bulb and reflector. Security and safety can also be gained by using motion sensor, which switch lights only when needed, rather than burning continuously.

To eliminate light trespassing lights can be bought with what is called full cut-off shielding, at very comparable price to the standard light fixture, so that no direct light can shines above the horizontal plane form the lowest part of the fixture. Existing light fixtures can be fitted with shielding, but the energy savings possible by replacing it with a more efficient light may be cheaper.

By Maurice Sluka

Published in the Prince George Astronomical Society’s magazine “PeGASus”