Starry, Starry Nights

1st January 2016

Light pollution is a growing problem, with detrimental effects on the environment and on health. Deborah Mulhearn looks at campaigns designed to restore our enjoyment of the night sky.

When was the last time you saw the stars (the ones in the sky, that is)? If you live in an urban area, the answer is probably a good while ago, or maybe when you were on holiday. To look up and see the Milky Way, the Northern Lights, a shooting star or a familiar constellation can be a magical and even life-changing experience.

The popularity of stargazing has certainly been boosted by discoveries from space missions and NASA’s robot rovers, and from TV programmes such as the BBC’s The Sky at Night and Stargazing Live. There has also been a growth in commercial stargazing ‘safaris’. It’s all helping to demystify the night sky.

But there is now so much light pollution, especially in our towns and cities, that views of the night skies are often obscured. “I can remember standing in the street in London as a young boy in the early 1950s and seeing thousands of stars,” says Bob Mizon, co-ordinator for the Commission for Dark Skies, a section of the British Astronomical Association set up to counter the growing tide of light pollution.

“You should be able to see between three and five thousand stars,” says Mizon, an amateur astronomer who tours schools in the south of England with his travelling planetarium. “But if you look up in central London today you’d be lucky to see half a dozen. London astronomers nowadays tend to focus on the moon, because that is pretty much all that can be seen.”

How do you know whether you are in a dark sky area, or one that suffers from light pollution? A simple – if unscientific – way to find out is to do a star count using the Orion constellation, usually visible in the winter skies. Orion is a hunter and easily identifiable from his ‘belt’, which comprises three bright and closely spaced stars. Look for the four stars that make a rough rectangle around this belt (like a pulled-in waist) and count how many stars you can see within the four ‘corners’. If you can see more than thirty you are in a dark sky area; if you can see fewer than ten, you have light pollution.

Light pollution is also detrimental to the environment, our health and our pockets, says Mizon, “There are many negative effects… but the main one is the incredible waste of energy. There is absolutely no need to leave office lights on all night, yet many companies do it. Migrating birds are also at risk, because they crash into brightly lit buildings. We don’t quite understand why yet, but it’s an enormous problem that kills millions of birds every year.”

The American Medical Association has now branded bad lighting a potential health hazard, and there are many studies looking at the negative health effects of poor lighting, including one from Israel, which makes the link between breast cancer clusters and brightly lit areas. Studies have also shown that light pollution can affect the body’s production of melatonin, a natural hormone that helps regulate our body clock and promotes good sleeping patterns.

But there have also been great strides to reduce light pollution, particularly in the more careful use of street lighting, says Mizon. “We’ve been talking to the Highways Agency, local authorities and lighting manufacturers for twenty-five years now and we’ve had a good response. All new motorway lighting has been downward shining since the 1990s, and street lighting is slowly being replaced with LED lights.” And you don’t have to be in the middle of the countryside to implement schemes. “We gave a good lighting award to Westminster City Council, for example, because their street lighting is all pointing downwards,” adds Mizon.

There are many campaign groups working to improve the quality of our night skies. The International Dark Skies Association (IDA) is based in Tuscon, Arizona, and awards different categories of ‘dark sky’ status, depending on the size and clarity of the area. The main stargazing destinations, as designated by IDA, are in the desert regions of the United States and South America. The remotest certified place to see dark skies is the AURA observatory in Chile. In Europe the best is considered by IDA to be the Tiede national park in Tenerife.

There are three IDA-designated ‘dark sky parks’ in the UK. The first was Galloway Forest Park in south-west Scotland, designated in 2009. The Elan Valley in the Cambrian Mountains in Wales now also has dark sky park status. Within these categories there are gold, silver and bronze tiers, depending on the size and proximity to light sources, and Kielder Forest National Park in Northumberland has gold tier status. Kielder is recognised as the UK’s premier dark sky zone, and the only site in England with a dark sky park designation. Kielder Observatory, which opened in 2008, has boosted ‘astro’ tourism in the region with its programme of public events, and the skies above it were designated in 2013.

There are also dark sky reserves, communities, sanctuaries and developments of distinction. UK Dark Sky Reserves include Exmoor, which was Europe’s first International Dark Sky Reserve, designated in 2011, and the Brecon Beacons National Park in Wales. There are local campaigns to have dark sky quality recognised by IDA above both the Isle of Wight and the South Downs in Hampshire.

Dark skies were identified as a special quality of the South Downs when it was awarded national park status in 2010. It is Britain’s newest national park and is currently applying for IDA dark sky reserve status. It’s not an easy process, and national parks, areas of outstanding beauty (AONB) astronomy clubs and residents’ groups have to work closely with their local authorities to achieve the status.

“First you need good mapping to show the dark skies in your area,” says Dan Oakley, dark skies project leader for the South Downs National Park. “Your local astronomy group may have local evidence, or there are apps you can download that turn your camera phone into a light quality meter. Otherwise you can buy a sky quality meter for around £100 from an astronomical supplier.”

Street lighting is the biggest contributor to loss of light quality, explains Oakley. “As the urban fringe encroaches on the countryside it pushes the darkness out with it,” he says. “But it’s about managing lighting rather than banning it, and making sure it is appropriate and downward directed. The newer style lights are much more optically efficient because they don’t scatter the light out and upwards as the old sodium lights do.”

The Campaign to Protect Rural England (CPRE) is currently updating its ‘night blight’ maps, first produced in 2003, when they showed a 26% increase in light pollution in the seven years between 1993 and 2000. The new maps will have a lot more detail and will be used to help local authorities control light pollution. And it’s not only urban areas that are affected.

“Light pollution doesn’t respect boundaries,” says Emma Marrington, senior rural policy campaigner at CPRE. “It can spread out into the countryside from a light source miles away. Airports, security lights, floodlights on sports grounds – they can all affect the view of the night sky.”

The maps will also help with applications for dark sky status, she adds. “It’s a longwinded process because the levels of light surrounding the area have to be assessed and this can take years, but it’s a huge achievement to be awarded the status, and once you have it, it can help boost tourism.”

The government introduced a national policy on the control of light pollution in 2012, and while progress is slow, councils are starting to respond. “The priority for local authorities is money, of course, and for some it includes energy saving,” says Marrington. “But our 2014 report, Shedding Light, gave an encouraging snapshot of the work being done at local level, where councils are agreeing to switch off street lighting at certain times or are replacing existing lighting with dimmer lights, which is more popular with the public. And it’s a happy coincidence that you can also see the stars.”

The buffer zones required by the IDA when nominating dark skies are difficult to establish in the UK, but there are other schemes that simplify the process for our more built-up areas. One exciting initiative is the Dark Sky Discovery scheme, which identifies the best places for stargazing around the UK, and encourages people to nominate their local dark skies. Once these ‘pockets’ of darkness are identified, the desire to preserve and promote tranquil night skies creates a virtuous circle. There are hundreds of amateur astronomy groups around the country, so go out and look at the stars. And don’t forget to turn off the light.

Find Your Local