Good News For Shaftesbury Stargazers – LEDs Have Reduced Light Pollution

The Cranborne Chase Area of Outstanding National Beauty is applying for International Dark Skies Reserve status in March. If the US based judging panels approves the bid, the status could bring extra cash into our local economy.

ThisIsAlfred.com’s Keri Jones joined a stargazing event and presentation at Ansty Farm shop on Tuesday as the AONB outlined their plans.

The Shaftesbury area offers stunning scenery with its green slopes and chalk downs. Most people think about our daytime views but our lack of light pollution means that our night skies are worth travelling to see. Most of the UK population cannot view the Milky Way because of the glow caused by artificial lighting. Cranborne Chase is surprisingly dark and it’s hoped that Dark Skies designation will encourage new tourists and help wildlife, which can become disorientated by bright light.

“If you look at light pollution maps from satellites in space, the Cranborne Chase AONB is the darkest place anywhere in South Central England. I have to go to Exmoor to find a place that is equally as dark,” explained Astronomer Bob Mizon. “I think it is partly to do with the topography – the lie of the land. As you come inland from Bournemouth, the land rises rapidly to a big ridge around Wimborne and Ferndown and then it goes down and up again. We have the river valleys here running east to west. Quite a lot of the time on the Cranborne Chase you are standing in a valley and you can’t see the distant towns and the sky glow that hangs above them.”

Bob Mizon, Amanda Scott and Linda Nunn

An Area of Outstanding Natural Beauty, or AONB, is similar to a National Park. And the Cranborne Chase AONB, which narrowly skirts Shaftesbury, includes Semley, East and West Knoyle, The Donheads, Ashmore and Compton Abbas. The AONB is asking councils within this area to tackle the sources of light pollution, to help the Dark Skies application.

“It’s not a statutory designation. It’s a kudos designation,” explains Amanda Scott, the AONB Dark Skies Advisor. Amanda says that the AONB plans to define a central core of dark sky villages. They’ll be surrounded by a buffer zone where the sky is brighter, nearer the population centres.

“It’s to protect the dark central core from at least 80% of the surrounding light pollution you might get from the urban areas. We’ll get quite a large central core because the skies are really dark but there will be a thin buffer around the outside to meet the requirements of being a reserve. That might include Iwerne Minster, which is quite dark but also close to Shaftesbury. As you get close to Blandford there will be a few villages which start looking a bit brighter but it’s all relative,” said Amanda. One of the villages with the lowest level of light pollution is just seven miles from Shaftesbury. “Tollard Royal is pretty dark at night,” said Amanda, who has undertaken readings using light pollution meters.

The AONB believe that it is possible to reduce the glow from housing, businesses or streetlights. Their astronomy adviser Bob Mizon says the lighting added when Shaftesbury’s new estates were built uses technology that doesn’t spoil the night sky view.

“There has been a huge amount of lighting change in Shaftesbury. There’s a lot less glare than there used to be. Shaftesbury now has LED lighting and nearly all LED road lights point downwards. The only problem is that some of them are too bright for the lighting task. You can always tell if a light is too bright. As you drive underneath them, the LED appears above you and it can be uncomfortable,” said Bob.

Bob Mizon

Bob says the recent lighting changes have increased opportunities for astronomers in and around Shaftesbury. He noticed the difference on Fontmell Down. “I was stargazing quite recently, close to Shaftesbury, and I could plainly see the Andromeda galaxy in the sky. It’s something you only see with the unaided eye from a really dark place. It’s two million light years away. You can see it glowing there. I am pretty sure that when Shaftesbury had the big, orange sodium lights, you would not have seen that,” said Bob.

But Astronomer Steve Tonkin, also present at the Ansty event, said the local light pollution could be reduced further. “They have made a major error with that. They have used blue-rich LED lights. Blue light scatters more than any other colour of light, which is why the sky is blue – sunlight is scattered. They are using lights that are far too bright for the purpose and the blue-rich LED lights scatter upwards. There are wonderful images of Milan, taken a few years apart, and you can see the difference before and after the LED lights were installed. It is much brighter afterwards. It’s a wasted opportunity.”

The AONB is keen to seize on the potential of Dark Skies designation because the Dorset and Wiltshire border is one of the best stargazing locations in the South. “At this very place, Ansty, we have measured one of the darkest skies in Southern England,” said Bob.

The Ansty Farm Shop staff turned off their outdoor lighting and our group headed into the pitch-dark car park, carefully and slowly. Some of us were armed with torches and headlamps. Others were just hoping not to walk into a boot or bonnet. The sky wasn’t entirely clear. There was some mist, but the moon was visible.

Steve is both a Fellow of the Royal Astronomical Society and a Wessex Astronomical Society member. He was on hand, giving guests a chance to gaze through a line of telescopes and binoculars. I was surprised that this location, next to the A30 and just minutes from Shaftesbury, was considered such an excellent viewing spot. “It is very dark and once you get rid of the night glow, which you tend to do after lights go off at around midnight and the traffic stops, it gets incredibly dark,” said Steve.

We could see the orange glow of the sky above Salisbury and Steve explained that later in the evening the glow of Poole and Bournemouth would become apparent. “It’s such a waste of energy and it confuses most night flying animals. It just takes away the night sky environment. We need to have less powerful lights, properly directed and we’d save a heck of a lot of money,” Steve said.

Steve guided me towards one of the binoculars, lined up on tripods at the end of the car park. It appeared to be a costly bit of kit. “It is expensive. It’s a 100mm binocular with changeable, angled eyepieces. The idea being that if I wanted to look at something overhead I wouldn’t have to tilt my head right back and see a physiotherapist the next morning.”

Steve encouraged me to peer through his binoculars. “So you can see the moon, and if you look at the left hand side, on the bottom, the line between light and dark is called The Terminator. There are craters being sunlit and at the bottom there’s a little bit of crater which seems detached from the rest of the moon.” It was so clear. And there was no sign of little green men waving back to me! “There is no atmosphere. It’s like Blandford Forum on a Friday night,” Steve laughed.

Steve is a firm believer in stargazing through binoculars. And Bob agrees that they’re best, especially for new astronomers. “Do not buy a small child a telescope. They won’t be able to use it because you have to find things. It’s like driving a taxi. You don’t jump into one and know where everything is. You have to learn it. Get binoculars. They are easy to use, you just point and look around the sky. Then get a telescope when you know what you are doing,” Bob said.

The men demonstrated free applications on an iPAD. There’s one that will make life easier for stargazing beginners. “Stellarium allows you to see through the clouds,” said Steve. “You can hold your tablet to the sky and it tracks where the stars and planets are in relation to your position.”

We headed back into the warmth of the farm shop café. Our £5 event fee included a hot drink and a cake. I wondered whether the old wives’ tale of carrots improving night vision also applied to carrot cake. Once everyone had refuelled, Bob turned on the overhead projector and loaded up his laptop with the realistic, 3D-like Stellarium software. He zoomed in and out of stars and solar systems and landed on planets. The software was like Google Earth – for everywhere that’s not on earth.

“There’s a huge amount of interest in space, especially amongst children. I have an inflatable travelling planetarium and I go to Scouts and schools. Teachers say there are two things that light up the eyes of children – space and dinosaurs. If they can see it, it turns them into scientists, mathematicians and historians. Astronomy is about everything,” said Bob.

I could understand the enthusiasm. The farm shop was full of people keen to learn more. Amanda said that the other Dark Skies Status areas have converted this passion for the planets into pounds for shops, hotels and guesthouses.

“Bed and breakfast businesses in places like the South Downs, Exmoor, Brecon Beacons and Snowdonia have been able to market themselves on the basis that they are close to a Dark Skies Reserve, which means they can get more business from astronomers and astrophotographers. Cranborne Chase AONB is beautiful but 50% of it is sky. We want to protect those dark skies.”

The Dark Skies designation would bring benefits for people in the adjacent areas and not just visitors. “It’s a resource for areas like Warminster and Salisbury. They can go into Cranborne Chase and see those lovely starry skies,” said Amanda.

During the evening Amanda offered advice on the right lights to buy if you want to reduce light pollution. The harsh lighting outside Guy’s Marsh Prison has concerned some locals and you may think that would be a sticking point. But Amanda says the AONB can advise on lighting solutions that both serve their purpose and protect the dark sky.

“It’s not a case of having no lighting. Local residents will need to have lighting outside a house just to be able to approach in the dark. It’s about having the right kind of lighting, which points downwards so the light goes to the ground where you need it and not into the sky. It’s also about the brightness of lights, so you have nothing brighter than is needed, and having motion sensors and time switches,” said Amanda.

Early next year, a US-based panel will assess the Cranborne Chase AONB Dark Skies bid. They’ll hear whether they’ve gained accreditation by early summer. “We’re putting the bid in at the end of March. The International Dark Skies Association will take 4-6 weeks to decide.”

In preparing the bid, Amanda has been touring villages and talking to locals. She says the proposal has been well received. “I’ve been walking around in the daytime, looking at external lighting. People stop me in the street because they want to know what I am doing. They think I am booking their car, which I am not! They’ve been really interested in what is happening.”

Amanda would like all locals to offer their backing, by taking two minutes to fill out an online pledge on the ChasingStars.org.uk website. “There’s a real commitment from people out there who really love the dark, starry skies,” said Amanda.

If you would like to meet the AONB team and astronomers in person, they are planning a second stargazing night at 7pm on 13th December at the New Remembrance Hall in Charlton. Remember to take a torch!