Horningsham Community
Horningsham Community

Cranbourne Chase AONB Dark Skies

The Right Light at Night


In October 2019, Cranborne Chase AONB became only the 14th International Dark Sky Reserve (IDSR) worldwide (there are now only 17). This prestigious status was awarded in recognition of the exceptional character of our dark skies in particular, and nocturnal environment in general.

We need artificial light at night for safety, for work, and for leisure, but nature needs the night, so how do we balance our needs and those of the nocturnal environment? The principles of responsible outdoor lighting are encapsulated in the ditty Right Light, Right Place, Right Time.

The last two of these are obvious. Right Place is simply to use careful aiming and shielding to direct the light to where it is needed and ensure that it does not intrude where it is neither wanted nor needed, especially upward into the sky. Right Time is when it will actually be useful, and this can be achieved by using timers or PIR motion detectors. On-all-night security lighting often merely acts as a beacon to advertise that there is something valuable nearby.

If you drive, you will have noticed that you need to wipe far fewer insects off your windscreen than even 5 years ago. You may also have noticed that you have far fewer moths and insects coming into a lit room if you leave a window open. These two reveal the long-term effects of the wrong sort of light: harsh, cold, bright white “blue rich” light. This has been devastating for nocturnal wildlife: amongst other harms, it is a direct driver of the “insectageddon” component of the biodiversity collapse. We are on course to lose 30% of our remaining insect populations in the next 20 years. The American Medical Association has already declared light pollution to be a health risk because of its adverse effects on human health. The Right Light is a softer “warm white” light of the minimum necessary brightness, which does not create glare or dark shadows that conceal what it should reveal.


You can use this handy flowchart to check if your outside lighting is dark sky friendly: https://tinyurl.com/2pbny5dv

Cranborne Chase AONB has funding available to support the movement towards Dark Night Sky friendly light fittings, both domestically and specifically for farmers and land managers through the Farming in Protected Landscapes programme, running until March 2024.

For more information, contact The AONB’s Dark Skies Adviser, Steve Tonkin at [email protected] .



Home Lighting Assessment
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Please do take a look at your properties lighting

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