Mobile Apps

Dark Sky meter App (iPhones)
The Award-winning Dark Sky Meter by DDQ helps you measure the night sky brightness with the press of a button. Get instant information about the night sky quality and contribute to creating a global map of sky darkness. See our Measuring Light Pollution page for more information.

Loss of the Night App (iPhones and Androids)
The Loss of the Night app turns your eyes into a light meter, allowing you to become a citizen scientist and report how bright the night sky is where you live! See our Measuring Light Pollution page.

F.lux (available for Mac OS/X, Windows, Linx, iPhones and iPads)
f.lux is a colour temperature app that makes the colour of your computer’s display adapt to the time of day, warm at night and like sunlight during the day. It makes your computer screen look like the room you’re in, all the time. When the sun sets, it makes your computer look like your indoor lights. In the morning, it makes things look like sunlight again.

Lux (Android phones free or paid versions)
Lux intelligently adjusts the brightness of your display based on the environment you’re in. It’s also able to adjust the screen temperature of your display automatically to make it appropriate for night usage. At sunset, you can have Lux automatically warm your display and switch to your Night profile. If you’re an astronomer, you can enable astronomer mode to cut out harsh white light.

Twilight (for smartphones or tablets)
The Twilight app makes your device screen adapt to the time of the day. It filters the flux of blue light emitted by your phone or tablet after sunset and protects your eyes with a soft and pleasant red filter. The filter intensity is smoothly adjusted to the sun cycle based on your local sunset and sunrise times.

Dark-Sky Activities to Enjoy at Home

Here are some great resources to enjoy the night sky, whether it be in your garden, through your living room window, or on a computer screen.  

Family Arts & Crafts

Contribute to Night Sky Citizen Science

Familiarize yourself with your night sky and contribute to important citizen science projects:

  • Globe at Night is your go-to international citizen-science program that people can do from their backyards at no cost.
  • Dark Sky Citizen Science Program offers three citizen science programs to measure how light impacts our view of the night sky as well as three projects to measure the diversity of life on Earth.
  • The Satellite Streak Watcher citizen science programs or on SciStarter
  • Loss of the Night as well as on a blog on SciStarter 
  • Dark Sky Meter is a phone app that acts like a Sky Quality Meter.

Virtual Tours

Can’t get out into the dark? Check out these options for exploring the night sky with virtual reality:

Press Release Example

This is an example of a post that has its category set to ‘Press Release’ and how it shows up in the press release section. Any new post can be set as ‘Press Release’ as well as any other categories.

Outdoor Sports Lighting

LED lighted soccer facility located adjacent to a residential neighbourhood. The photo was taken approximately 150 meters from the field edge.

There has been a significant increase in the number of outdoor sports areas built in urban and suburban neighbourhoods; at schools, parks, and outdoor play areas. The excessive amount of light associated with these is a nuisance for neighbourhoods and creates significant environmental impacts.

Historically it has been difficult to control the light “lumens” to the level needed for dark-sky compliance because light fixtures used older bulbs lamp sources (incandescent, metal halide, high-pressure sodium, etc.). These bulbs and the reflectors housing them are too large to effectively shape and focus the light onto the field of play, causing light spillage, glare, and impacting nocturnal wildlife and the surrounding communities.

very bright uplighting glare from badly installed sports lighting.
Very bright uplighting glare from badly installed sports lighting (near Stonehenge). Image: CfDS
These two photos were taken at the same facility, on opposite sides of the access road. (Left) Pointed toward the athletic field. (Right) Pointed toward the neighbourhood.

Recent advances in LED lighting technology offer lighting designers the opportunity to develop lighting sources strong enough to light the field of play, BUT small enough to be effectively shielded. With this technology, recreational sports lighting can be configured and designed to be effectively shielded to illuminate the field of play and minimize or eliminate glare and light trespass.

The IDA Technical Committee released the criteria for IDA Community-Friendly Outdoor Sports Lighting in March 2018:

  1. Minimises neighbourhood lighting nuisances by greatly reducing the allowable spill and glare disruption. Quantitative pass/fail thresholds are established.
  2. Manages high angle glare, thus off-site light trespass and sky glow effects due to direct and reflected light are dramatically lower.
  3. Mandates curfew requirements, thus mitigating neighbourhood nuisance factors and sky glow effects which benefit flora/fauna and night sky enthusiasts’ and astronomers’ views of the night skies during peak viewing periods.
  4. Limits the class of play to recreational levels, thus discouraging over-lighting practices.
  5. Promotes “Best Lighting” practices that minimize lumen densities, which reduces energy consumption, benefiting the environment at large.
Bad Sports Lighting in West England showing two pictures one with the lights on and terrible glare, and the other with lights off and a good dark sky.
Bad Sports Lighting in West England, turned on or off.

Now sports lighting designers can apply to IDA-UK for certification of their designs. Fields in full compliance with the IDA Criteria for Community-Friendly Outdoor Sports Lighting (PDF) can then receive recognition from IDA and an award plaque, recognising the minimisation of light pollution.

Lighting Laws & Policy

Lighting regulations are an important tool for setting reasonable limits on light pollution. IDA-UK supports cities to adopt and enforce policies that call for shielded, downward-pointing lighting, lighting timers and other sensible controls. Doing so conserves energy, lowers costs and carbon emissions and helps to minimize glare, light trespass and skyglow.

Our Policy Goals are to Update the Existing Legislation

From the APPG For Dark Skies Policy Plan:

The existing legal framework regulating light pollution is derived from statute and therefore can only be amended by Parliament. New legislation is therefore likely to be necessary to truly protect the UK’s dark skies and night-time landscape.

1.    Strengthen the National Planning Policy Framework: for the first time ever, make extensive specific reference to the control of obtrusive light in the National Planning Policy Framework.

2.    Expand the scope of the planning permission process: introduce regulations for exterior lighting that are similar to those which currently cover advertisements.

3.    Strengthen Statutory Nuisance Provisions: remove exemptions to give local authorities a more effective method of preventing nuisance lighting. ”   

APPG For Dark Skies
  • For a detailed look at UK laws, head over to the CfDS webpage on lighting law by clicking here.
  • For a more in-depth look at how the APPG for Dark Skies want to change existing legislation click here.
  • The governments light pollution planning page is here.

The IDA/IES Model Lighting Ordinance

In 2011 IDA and the Illuminating Engineering Society of North America approved the Model Lighting Ordinance (MLO), an outdoor lighting template designed to help councils develop outdoor lighting standards that reduce glare, light trespass, and skyglow. The MLO is a valuable guide for environmentally responsible outdoor lighting in the USA that has applications in the UK as well. It encourages the broad adoption of comprehensive outdoor lighting ordinances without burdening cities with the extensive staff time and resources needed to develop their own codes.

The MLO offers several innovations to outdoor lighting regulation, including the use of lighting zones to classify land use with appropriate lighting levels for each. The MLO also makes use of the “BUG” (Backlight, Uplight and Glare) classification of outdoor lighting fixtures to ensure that only well-shielded fixtures are used. The MLO is a useful tool that the IDA-UK uses to support similar lighting changes across the United Kingdom.

What to Consider Regarding LEDs

As many communities move to embrace LED lighting, the landscape of nighttime lighting is changing rapidly and dramatically. While some industry representatives tout these new fixtures as being “dark sky friendly,” that’s not usually the case.

Communities considering switching out their older streetlights for LEDs should read:
Printable LED Information Handout (PDF)
Visibility, Environmental, and Astronomical Issues Associated with Blue-Rich White Outdoor Lighting (PDF)

Bad Streetlights

A bad example: All these streetlights spill light in all directions and up into the sky. With no shielding, the exposed globes cause glare, making it difficult to see. Photo by Jim Richardson

Sometimes streetlights are badly designed or installed incorrectly and end up shining lights into your home and garden, This is known as light trespass.

If the bad lighting is from a neighbour’s light, see our My Neighbour’s Lighting webpage.

If the light trespass comes from a street light, it’s unlikely that you’ll be able to get the offending streetlights removed but polite yet firm action may help you get your peace of mind and dark skies back.

a street showing bad streetlights that produce glare, light trespass and uplighting.
Bad streetlights that produce glare, light trespass and uplighting. Image: Chris Baddiley

It’s probably the council who are responsible for streetlights and there’s usually a department dedicated just to street lighting. You should be able to call your council switchboard to find out who to email or speak to, and sometimes the council website will have a form you can fill in to make a complaint. However you do it, explain how your quality of life has been diminished by the streetlight/s and request a “full cutoff shield” or a “house-side shield” for the most offending lights.

light from streetlights pours into a house on the staircase through a window
Light Trespass from an unshielded streetlight into a house. Image: CfDS

Shields for streetlights are available from most streetlight manufacturers, although your council may initially tell you otherwise. Be persistent, you are simply requesting that the light shining in your direction be directed toward the ground where it belongs. If this approach fails or your written requests go unanswered, contact your local councilor or MP and request action and support for your position, but be diplomatic. Many politicians might feel proud about lighting up the streets, making people feel safe, and deterring crime in spite of the fact that this isn’t the case and that the evidence linking brighter lighting to less crime is inconclusive at best.

By tactfully and persistently making your case about the effects of light trespass on you and your property, eventually, you should prevail. You could offer to pay for the shields, but only as a last resort.

Outdoor Lighting Basics

IDA-UK recognizes that we need good outdoor lighting at night, but any required lighting be used thoughtfully. To minimize the harmful effects of light pollution, lighting should

  • Only be on when needed
  • Only light the area that needs it
  • Be no brighter than necessary
  • Minimize blue light emissions
  • Eliminate upward-directed light

Glossary of Lighting Terms

Types of Light (The Science Bit…)

Most people are familiar with incandescent or compact fluorescent bulbs for indoor lighting, but outdoor lighting usually makes use of different, more industrial sources of light. Common light sources include low-pressure sodium (“LPS”), high-pressure sodium (“HPS”), metal halide, and, most recently, light-emitting diodes (“LEDs”).

LPS is an old technology that is no longer being manufactured. It was favoured for use around observatories and some environmentally sensitive areas. Narrow-band amber LEDs emulate the colour.

HPS is commonly used for street lighting in many cities. Although it still emits an orange-coloured light, its colouring is more “true to life” than that of LPS.

In areas where it’s necessary to use white light, two common choices are metal halide and LEDs. One of the advantages of LED lighting is that it can be dimmed. Thus, instead of always lighting an empty street or parking lot at full brightness, LEDs can be turned down or off when they aren’t needed and then brought back to full brightness as necessary. This feature both saves energy and reduces light pollution during the night.

Because of their reported long life and energy efficiency, LEDs are rapidly coming into widespread use, replacing the existing lighting in many cities. However, there are important issues to consider when making such a conversion. See our LED Practical Guide for more information.

Colour Matters

It is crucial to control upward-directed light, but we know that the colour of light is also very important. Some lights have large amounts of blue light in their spectrum. Because blue light brightens the night sky more than any other colour of light, it’s important to minimize the amount emitted. Exposure to blue light at night has also been shown to harm human health and endanger wildlife. IDA recommends using lighting that has a colour temperature of no more than 2,700 Kelvins.

Lighting with lower colour temperatures has less blue in its spectrum and is referred to as being “warm.” Higher colour temperature sources of light are rich in blue light. IDA recommends that only warm light sources be used for outdoor lighting.

several diagrams showing the light spectra of various types of artificial and natural light.
Sunlight vs L.E.D. vs Florescent Light Spectra Comparison

Lighting Regulations and Policies

Outdoor lighting regulations are a great tool for ensuring that councils implement good, safe outdoor lighting. Well-written regulations, with proper lighting installed, will save the public money and increase safety.

  • How can you identify if your community has lighting regulations?
  • How to ensure lighting regulations are enforced
  • How to advocate for a lighting regulations

How to Identify if Your Community Has Lighting Regulations

Contact your local council and ask, or check your city’s website to see if you can search its laws and regulations. If you can’t find the relevant information on the website, try a web search using your town or city’s name along with the words “lighting regulations.”

Key phrases that you are looking for in these regulations are; “outdoor lighting,” “exterior lighting,” “light pollution” or “light trespass.”

Your search may turn up policies that regulate specific types of lighting; a common example of this is language in an ordinance regulating outdoor signs that incidentally mentions lighting. Look for search results that suggest a general and freestanding policy, which tends to be comprehensive in nature. Often these sections will be headed with simple descriptive titles like “Outdoor Lighting”. If you don’t find this, it’s a good bet that your community doesn’t have an outdoor lighting policy.

How to Ensure Lighting Regulations are Enforced

Many towns and DarkSky advocates think that the adoption of lighting codes/laws/policies is the end of their efforts. Instead, it’s often the beginning and ongoing education is key. Otherwise, a community might forget why it even adopted the original code and how it helps its citizens. The details of code enforcement may or may not be spelt out in the outdoor lighting regulation itself, so check the code to be sure. Many regulations are complaint-driven, but there are things to look out for before making a complaint about someone’s lighting:

  1. First, DarkSky recommends always having friendly neighbourly discussions with lighting offenders before making a complaint to the local government.
  2. Second, some codes have a grandfathering provision exempting lighting that was in place before the ordinance was passed. If your city has such a provision, many older lights may be exempt (e.g. listed buildings). There may be other exceptions or conditions in the code too, so be sure to look for those before making a complaint.

If a complaint is valid, then city officials might need to make a nighttime site visit to verify the claim. Often they’ll be reluctant to – that’s understandable as most of us don’t want to work beyond our normal work schedule. Stick to the facts (rather than making an emotional appeal), but be persistent when discussing your concerns with city officials. Remember that while your city works for you, it’s likely that the code enforcement office has too much to do and not enough resources to get everything done at once.

How to Advocate for an Outdoor Lighting Ordinance

Getting new laws passed is a lengthy process. A good way to start is to make an appointment with a member of city staff, the mayor or your councillor or MP. Don’t worry if your first meeting ends up being a short one. It’s entirely possible that your local officials don’t know what a lighting policy is or why one would be needed. It’s also very important to be prepared with relevant and objective information (you might want to check out our Lighting for Policy Makers webpage). Keep the discussion focused on the positive outcomes for the city and try to anticipate any questions that the officials might ask about costs and safety issues.

DarkSky UK has many resources that can assist you, which you can find in our “members” section.

In developing a new policy, there will be many factors to consider. Beyond the basic shielding requirements, DarkSky UK recommends that an ordinance address light trespass, lighting curfews and spectrum (see our LED guidelines)

There are a host of other questions that need answering, including

  • Should lighting zones be adopted?
  • Are any special considerations needed to protect environmentally sensitive areas or an astronomical observatory?
  • Should the new rules be applied to older, non-conforming lighting?
  • Should there be a timeline for when all lighting must be brought into compliance?

Lighting For Policy Makers

Why Should Your Town or City Worry about Light Pollution?

Energy Waste and Carbon Emissions

In an average year in the U.S. alone, outdoor lighting uses about 120 terawatt-hours of energy, mostly to illuminate streets and car parks. That’s enough energy to meet New York City’s total electricity needs for two years!

DarkSky International estimates that at least 30 percent of all outdoor lighting in the U.S. alone is wasted, mostly by lights that aren’t shielded. That adds up to $3.3 billion and the release of 21 million tons of carbon dioxide per year! To offset all that carbon dioxide, we’d have to plant 875 million trees annually (see our Light Pollution and Energy Waste page).

Negative Effects on Wildlife

Numerous studies have shown that artificial light at night has numerous negative and deadly effects on many types of wildlife including birds, amphibians, insects and mammals. The evidence and research is also growing to demonstrate that nocturnal pollinators are being hit hard by thoughtless lighting.

What about Crime and Safety?

There is no clear scientific evidence showing that increased outdoor lighting deters crime. While brighter lighting may make us feel safer, poor outdoor lighting can actually reduce our personal safety. A study conducted by the city of Chicago found a correlation between increased crime and brightly lit alleyways. A study prepared by the U.S. National Institute of Justice concluded: “We can have very little confidence that improved lighting prevents crime.”

In fact, glare from bright lights creates shadows where criminals can hide. Some crimes like vandalism and graffiti thrive on lighting. Glare can also be dangerous to pedestrians and drivers. It shines into our eyes, constricting our pupils, which diminishes our ability to adapt to low-light conditions.

A Problem that has Simple Solutions

The good news is that your town can have it all – environmentally responsible lighting that helps keep citizens safe. When lighting is shielded, it’s directed down on the ground where it’s needed, which minimizes glare, light pollution and carbon emissions, and saves money.

Why Outdoor Lighting Policies Matter

Outdoor lighting policies are a great tool for ensuring that towns and cities implement good, safe outdoor lighting. A well-written policy, with proper lighting installed, will save the public money and increase safety. DarkSky International, in collaboration with the Illuminating Engineering Society (IES), created the Model Lighting Ordinance (MLO) to make it easier for municipalities to adopt good lighting plans. This is a USA-based policy but forms a good foundation for policy and legislation in the UK.

LEDs and Outdoor Lighting

Many towns and cities are replacing older, conventional, lighting systems with new, energy-efficient, light-emitting diodes (LEDs). However, energy efficiency is just one piece of the puzzle in improving outdoor lighting at night.

DarkSky International has developed a set of recommendations for towns and cities considering the installation of LED lighting systems. These recommendations take into account a number of important considerations and provide guidance for selecting outdoor lighting that increases energy and cost savings, enhances safety and security, protects wildlife, and preserves the nighttime environment.

My Neighbour’s Lighting

When a neighbour (or the council) installs outdoor lighting which also lights up your home, or shines through your windows, this is called “light trespass”. We don’t get involved in neighbourhood disputes BUT we can give you some useful information to help solve this problem in a simple, professional and friendly way. The first step is that your neighbour probably doesn’t realise there is a problem so its a good idea to have a friendly chat to begin with and maybe show them what their light looks like from your point of view. (A little goodwill goes a long way.)

Many people believe that more and brighter lighting makes us safer, but there is no solid evidence suggesting that’s true. In fact, glare from unshielded lights can create shadows where criminals hide. And bright lighting can even make it easier for criminals to work.

So, how do you talk to your neighbour about this situation?

(If the light trespass is from streetlights, see our Bad Streetlights page.)

Practical Actions:

  • Make friends, not enemies. Your neighbours probably don’t even realize their lighting is bothersome.
  • Stay positive and don’t argue. Be tactful and understanding about your neighbour’s right to light their property and to feel secure.
  • Suggest alternatives to their current fixture. Ask them to move the light, shield it, or add a motion sensor so it’s activated only when needed. Offer to help get this done.
  • Be helpful. Talking to your neighbour is a great opportunity to be an advocate for good lighting. There are many reasons to use dark sky-friendly lighting.
  • Have a list of shielded light fixtures to suggest as alternatives to your neighbour’s current lighting. Use our Fixture Seal of Approval database to find dark sky-friendly fixtures and devices.
  • Remember that everyone wants the same thing: a chance to relax in his or her own environment. Work together to create an atmosphere that benefits the community
  • Write a letter, take a picture of how the light impacts your home and garden. You may find it useful to put your thoughts on paper. We have provided a Sample Letter to Your Neighbor to get you started. Additionally, here is a recorded presentation on this subject.
Awful, cheap "security" light as sold by DIY Stores. Do not use.
Awful, cheap “security” light as sold by DIY Stores. Very bright, 5000 Kelvin, usually pointed upwards. Replace as soon as you can! Image: Bob Mizon