Dark skies are defined by the Oxford English Dictionary as "places where the darkness of the night sky is relatively free of interference from artificial light."
Between 1993 and 2000 light pollution across England increased by 24%. Today less than 10% of the UK population can enjoy a view of our own galaxy, the Milky Way. To put this another way, more than 90% of the UK population is now denied a view the sky which was taken for granted for almost all of human history – a view which has fired the imagination of generations of people and in the process inspired countless artists, poets, musicians, mathematicians, scientists and philosophers. Without the night sky acting as a source of creativity and questioning, some of the most important scientific discoveries may not have been made nor works of art produced.
The High Weald has some of the darkest skies in the South East. Sky Quality Meter (SQM) readings taken around Wadhurst indicate skies as dark as 21.09 mags/arcsec2 – a figure that corresponds to a Silver Tier International Dark Sky Reserve, described by the International Dark Sky Association as being: “Night-time environments that have minor impacts from light pollution and other artificial light disturbance, yet still display good quality night skies and have exemplary night-time lightscapes.”
The unusually dark skies over the High Weald AONB have been identified as worthy of conservation by the International Dark Sky Association (IDSA). However light pollution is rapidly increasing and our dark skies may not exist for much longer.
View light pollution change in the South East 1993 - 2000.
You can use this interactive map produced by the Campaign to Protect Rural England (CPRE)to find out more about light pollution in your area of the High Weald.
- Wastes energy and money
Inefficient lighting wastes over £1 billion per annum in the UK, with streetlights alone wasting over £100 million – all of which represents an enormous amount of money spent on generating light that is wasted directly into the sky.
- Detrimental to wildlife
Poorly designed lighting can affect the foraging, mating, and migratory behaviours of a wide range of nocturnal wildlife. Bats can become disorientated by artificial lighting and insects, like moths, can be killed by collisions with hot bulbs, become concentrated around a light and thus be easily predated, or get too exhausted to feed or reproduce. Thousands of migrating birds are also killed each year in collisions with unnecessarily illuminated buildings.
- Harmful to human health
Prolonged disruption of the circadian rhythm is linked to sleep disorders, obesity, depression, diabetes, and an increase in the growth of cancer cells.
- Doesn’t necessarily improve safety or reduce crime – lighting can actually make a place more unsafe!
Believe it or not, but too much lighting can threaten security by compromising vision with glare and casting harsh shadows where criminals can hide. To show how this can happen, just look at how the intruder disappears when you change angle of the light on this interactive simulator).
And there are more profound reasons that light pollution and the loss of dark skies matter. It denies every one of us – not just astronomers – the opportunity to experience an important part of our natural and cultural heritage: the majesty of the night sky. As the International Dark-Sky Association puts it:
"A lost view of the stars extinguishes a connection with the natural world and blinds us to one of the most splendid wonders in the universe. Children who grow up without the experience of a starry night miss invaluable opportunities to speculate about larger questions and to learn about the environment and larger world.”
We’ve produced a range of activity cards for schools to help them count stars and measure light pollution. Children are able to learn about the importance dark skies, as well as a number of subjects in the Key Stage 2 curriculum, including Light, Environmental Impact, and Earth & Space. The cards are freely available on our website and are already being used by a number of High Weald Hero schools. If you want to have a go at counting the stars, download the primary school light pollution activity sheets for free!
- Only use light when you need it and only use as much as you need for that purpose – anymore is just wasted, so avoid using brighter lights than absolutely necessary
- Install lighting only where necessary and always direct it towards the ground
- Turn oﬀ lights when you don't need them
- Use fully shielded fixtures around your home and encourage their use at your workplace and elsewhere
- Use energy saving features such as timers, dimmers, and motion sensors in all outdoor lighting, and avoid using inefficient high wattage light sources (i.e. ones that produce less light per watt)
- Always remember to draw your curtains or blinds at night to prevent intrusive light unnecessarily spilling out of your home
- Use long wavelength light (light that has a red or yellow tint rather than very white or blue lights) to minimize impact
- Promote the use of intelligent and effective outdoor lighting in your community
- Educate your friends and neighbours about the economic, environmental and security benefits of good outdoor lighting
Also, it’s worth playing around with this fun interactive light pollution simulator. It’ll give you a better idea of how different types of lighting can create or limit light pollution, as well as the striking impact poorly designed lighting can have on the night sky and surrounding environment.
The main aim is to raise awareness of the value of dark skies, and in the process inspire people about astronomy and the importance of preserving our shared view of the stars.
“An IDA Dark Sky Community (DSC) is a town, city, municipality, or other legally organized community that has shown exceptional dedication to the preservation of the night sky through the implementation and enforcement of quality lighting codes, dark sky education, and citizen support of dark skies.” - International Dark Sky Association
Some communities within AONBs and National Parks across the country are work towards becoming an International Dark Sky Community certified by the International Dark-Sky Association. However its isn't easy; there are currently only seven other International Dark Sky Communities in the world!
Campaign for Dark Skies lighting guidelines – Guidance from the lighting experts at the Campaign for Dark Skies. Advice to save money, increase safety, and minimise light pollution.
Institute of Lighting Professionals lighting guidance – Information from the Institute of Lighting Professionals on simple ways to reduce of obstructive light pollution.
The International Dark Sky Association website – A treasure trove of information and downloads on dark skies and light pollution (both its impacts and how to prevent/limit it) from the International Dark-Sky Association. There's a search to find approved Dark Sky Friendly lighting and illustrations of acceptable versus unacceptable outdoor light fixtures.
The British Astronomical Association’s Campaign for Dark skies website – Provides a useful overview of light pollution, its impact in the UK, why it matters and what you can do about it, as well as some key definitions.
Flagstaff Dark Skies Coalition – A useful webpage on how lamp spectrum affects light pollution, with particular reference to the potentially negative impacts of increasingly popular LED lighting
SKYGLOW – A fantastic interactive overview of light pollution in the UK and how it's changing.