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Published 3rd May 2013 by

Light pollution is defined as any source of artificial light that shines outside the area it is intended to illuminate. It has become a growing problem for the past couple of decades and is a particular problem for astronomers as they are quite literally blinded by the light.
Observational Astronomy Series
  1. A Beginner's Guide To Stargazing
  2. Dark Eye Adaption - How We See In the Dark
  3. Light Pollution
  4. Using Star Charts and Measuring Distance
  5. Top Tips for Binocular Astronomy
  6. Moon Watching - How to Observe the Moon
  7. Buying Your First Telescope
  8. Your First Night With Your First Telescope
  9. Sky Orientation through a Telescope
  10. Polar Alignment of an Equatorial Telescope Mount
  11. All About Telescope Eyepieces
  12. Useful Astronomy Filters for Astrophotography
  13. How to Photograph Constellations

In the words of Sir Patrick Moore: "Light pollution is increasing. Unless something is done, future generations may never see the stars."

Light Pollution in Bristol

Light Pollution in Bristol

Clean Neighbourhoods and Environment Act 2005

Early in 2006, the first UK law expressly aimed at tackling the problem of light pollution came into effect. The Clean Neighbourhoods and Environment Act 2005 makes "exterior light emitted from premises so as to be prejudicial to health or a nuisance" a criminal offence. It adds exterior lighting as a potential nuisance in the view of the Environmental Protection Act l990, along with already recognised nuisances like noise and odours.

Both the British Astronomical Association and the Campaign for the Protection of Rural England (CPRE) define light pollution as any origin of artificial light that shines outside the area it is intended to illuminate. This includes light that is directed above the horizon into the night sky, creating skyglow, or which creates a danger or nuisance by glare. Skyglow is the light that catches particles in the atmosphere, creating an orange halo of light above a town or city at night and blocks out the stars. Figures from the CPRE show an average increase in skyglow of 24 percent between 1993 and 2000 for the UK with street lighting and floodlighting generally to blame.

Effects of Light Pollution on the visible stars

Effects of Light Pollution on the visible stars

While it is possible to see magnitude +6 stars from dark sites, city dwellers are restricted to magnitude +3 at best. Light that has taken many millions of years to reach us from space is blocked in the last milliseconds of its journey due to light pollution. Naked-eye objects are reduced to binocular objects, and the beauty of the Milky Way is rendered invisible from city skies. Powerful 500-watt floodlights, often misleadingly named "security lights", are a common cause of light pollution, as are sodium street lights a cause of light pollution.

Under the new law, the state takes on the burden of the action and prosecutes the perpetrator. This is preferable in some ways but comes at a cost. In order to be a criminal statutory nuisance, the offence must be damaging to people's health or interfere with a person's legitimate use and enjoyment of the land and be more than just an irritant. It must also come from a legally definable "premises" in order to invoke the criminal law.

Light Pollution and your Environmental Health

If you're a victim of nuisance lighting and light pollution you can now report the matter to your local environmental health office which is part of your local council. The officer, after trying mediation, will then have to decide, based upon the new guidelines, whether the lighting could be a nuisance. If it is then the officer will ask for the nuisance to be reduced or removed, for example by angling the offending light downwards. If the perpetrator fails to do this, the officer may take the matter to court and the perpetrator may be ordered to abate the nuisance and possibly fined. Unlike the old law, all of this will be without financial cost to the victim.

If this does not have the satisfactory outcome, section 82 of the Environmental Protection Act 1990 provides a victim with the right to a private action in a magistrates court if they feel their environmental health officer has failed to act. The magistrates will need all the relevant facts, including the local authority's view, and so this kind of private action is not a failsafe.

Court action should not be regarded as an initial step. Instead, if you are a victim you should first try to discuss the nuisance with your neighbour. A negative or abusive reply from them provides further evidence for use in court. If you are assigned an environmental health officer, he or she will expect you to try mediation before court action. Although the statute is silent on street lighting, it is not expressly exempt, but it is unlikely that the provisions will apply.

What's Included and Excluded in the Law


This is covered, and includes 500 watt "security" lights. Skybeams may also be covered, but the local authority must be convinced that your property is adversely affected.


Street lighting is not expressly excluded, but it is likely to conform to the legal definition of premises, and so will probably escape liability. Many cities are replacing their streetllghts with better designs that minimise light pollution by emitting no light above the horizontal. But the new brighter lights are often on longer poles and may shine into windows, or across gardens, creating a glare nuisance. This is a gain on one hand and a loss on the other.


The sorts of premises from which light will be covered include houses, blocks of flats, shops, supermarkets, shopping centres, office blocks, pubs and car parks (public as well as private).


There are a number of exempted premises under section 102(4) of the Act: airports, harbours, railway or tramway premises, bus depots, public service vehicle operating centres, goods vehicle operating centres, lighthouses and prisons are all outside the legislation. The reason for the exemption is that these premises need lighting for operational and safety reasons.


Other business premises and sports grounds are included in the Act, but have the defence of "best practicable means", This means that, legally, there is no nuisance if all reasonable steps have been taken to minimise the nuisance, but the purpose of the light trumps the remaining nuisance.

The attitude of both local authorities and the courts in interpreting what may constitute a nuisance or "best practicable means" is fundamental to the success of the new law.

Beacons of Bother

Light pollution can come from any type of light, but the main forms are shown below.



Uplighters are usually used to illuminate historic buildings or landmarks. Low powered lights may cause minimal light pollution however most are overpowered and represent a considerable source of light pollution.

Recreational Lighting

Recreational Lighting

Recreational floodlighting, such as that used on playing fields, is often very powerful to provide adequate lighting for participants and spectators and causes significant light pollution. Thankfully these lights are not on all night, nor every day.

Security Lights

Security Lights

Floodlighting used as a security light are usually overpowered and badly aimed. Glare caused by poor positioning can actually aid intruders rather than deter them.

Car park floodlights

Car park floodlights

Car park floodlights are usually overpowered and poorly directed with most of the light reflected into the sky.

How to take Action against Light Pollution

Step 1

Talk to your neighbour; many may be converted if they're invited over to observe and see first-hand the nuisance they're causing. In one case, a neighbour was found to repeatedly put their lights on to 'help' an astronomer see what he was doing! Also, consider mediation rather than court action, which could lead to a feud.

Step 2

Use the new law and complain to your local authority's environmental health office. Think carefully about your complaint and give clear reasons why your health - or enjoyment of your property - is being adversely affected; for example, the light may stop you sleeping, or it may shine across your observatory.

Step 3

If your local authority will not act, you can bring a statutory nuisance case to a magistrates' court yourself under section 82 of the Environmental Protection Act 1990. The magistrates will ask why your local authority did not act, and may be swayed by this.

Step 4

If all else fails, use private nuisance in common law. You will have to prove on the balance of probabilities that the light is a nuisance. One defence is the "hypersensitive complainant", where your neighbour alleges you are being unreasonably sensitive in looking at the stars.

Step 5

Often, the solution to light nuisance is to angle the light downwards, but if all other means have failed, see www.courtservice.gov.uk for details about suing. You could even consider taking out an ASBO, as this can be granted to individuals as well as local authorities.

More Information

Tutorial Series

This post is part of the series Observational Astronomy. Use the links below to advance to the next tutorial in the couse, or go back and see the previous in the tutorial series.

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