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.
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.
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.
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:
Minimises neighbourhood lighting nuisances by greatly reducing the allowable spill and glare disruption. Quantitative pass/fail thresholds are established.
Manages high angle glare, thus off-site light trespass and sky glow effects due to direct and reflected light are dramatically lower.
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.
Limits the class of play to recreational levels, thus discouraging over-lighting practices.
Promotes “Best Lighting” practices that minimize lumen densities, which reduces energy consumption, benefiting the environment at large.
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.
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.
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:
First, DarkSky recommends always having friendly neighbourly discussions with lighting offenders before making a complaint to the local government.
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?
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.
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.
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.)
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.
How many exterior lights do you have around your home or property? Are you sure? Have you carefully considered each fixture’s need, function, or design? Are you minimizing light pollution in your own backyard? If not, you’re not alone. Unfortunately, much of our outdoor residential lighting is inefficient, poorly installed, or altogether unnecessary.
These misguided lighting practices contribute to light pollution, disruption of wildlife, impact human health, and waste money and energy. As of 2018, the average American wastes 41-103 pounds of CO2 per year on excessive residential outdoor lighting alone (1). Across the country, this amounts to at least $1.4 to $3.5 billion wasted each year, unnecessarily lighting the dark around our homes. Our analysis also indicates that these numbers may grow as Americans are likely consuming more exterior lighting than ever before (2).
Here’s the bright side: Light pollution is completely reversible.
DARK SKIES START AT HOME
Want to protect the night from light pollution? Get started in your own backyard (or front porch, walkway, bedroom window, rooftop – anywhere!)
Follow this step-by-step guide to conducting an outdoor lighting assessment around your house, apartment building, property line, community centre, or wherever to evaluate the impact of your light on the night. After completing the steps to make your home dark sky friendly, you can download and display a Dark Sky Friendly Home Certificate!
BASIC LIGHTING PRINCIPLES
With responsible lighting practices, it is possible to reduce light pollution and create a beautiful, healthy, and safe lit environment where you live and work. Let’s learn the basics and put them to work.
Even the simplest actions can make a big difference. DID YOU KNOW? 20% – 50% of outdoor residential lighting is lost to the night sky, due to poor shielding alone (3).
FINDING DARK SKY-FRIENDLY LIGHTING
Did you know? DarkSky works with lighting manufacturers and home retail stores so that you can easily source DarkSky-approved lighting.
…MY NEIGHBOR’S LIGHTING?
So you’ve addressed all your problem lighting, but what about the lighting that is beyond your control? Maybe your neighbour’s lighting is shining in your bedroom window, or your landlord or property manager needs to make changes. Check out these tips for working with your neighbour’s lighting.
It’s important that your property is safe and responsibly lit to protect you from potential hazards, support wayfinding, or deter potential crime. But brighter does not equal safer. In fact, too much lighting can have the opposite effect. Learn more about lighting, crime, and safety.
Estimates suggest that on average street lighting accounts for about 50% of a city’s total light emissions (4). Learn what you can do about streetlights in your community.
I’VE ADDRESSED THE ISSUE AT HOME, NOW WHAT?
Ready for the next step? Learn what you can do to take action today for a better night tomorrow. The universe will thank you.
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.
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.
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.