Black sky at night, stargazers' delight

Astronomers are waking up to the brilliant celestial views from the Galloway Forest Park
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The Independent Online

Boasting hundreds of square miles of deserted woodland, lonely lochs and boggy moor, the hills of the Galloway Forest Park have long provided a refuge for lovers of the rugged outdoors. Soon, many of those making their way to this corner of south-west Scotland will be seeking a glimpse of somewhere even more distant from the clamour of human activity.

This weekend, representatives of the International Dark-Sky Association (IDA), an organisation dedicated to preserving the night sky from the effects of light pollution, will travel to the park to test claims that the region affords the darkest and clearest views available to stargazers in Europe.

Using sensitive equipment, experts will be asked to confer on the forest the status of a "dark sky park" – making it the first place outside North America to receive the accolade. Should it be successful, national parks across England, including Exmoor and the Peak District, as well as the Brecon Beacons in Wales are expected to follow in its footsteps.

Galloway measures just three on the Bortle scale – a sliding register of light in which a major city such as London would be marked as 10 while the night sky above a point in the Pacific Ocean would be recorded as one. The inky blackness is disrupted only by the faint glimmer over the horizon of the lights of Glasgow an hour and a half to the north, and from Belfast to the west. The only major source of light within the park emanates from the hamlet of Glentrool, where 23 lights shine out.

Steve Owens, the UK co-ordinator for Unesco's International Year of Astronomy, said: "We have lost the experience of looking at the dark skies because most people live in cities and towns, which are badly affected by light pollution. Some might be able to find the North Star or the Plough but most would be unable to identify any constellations at all," he said.

"Looking at an unspoilt night sky speaks to something very primitive in us. Astronomy was one of the first instances when human beings encountered something outside their experience and tried to explain it."

Because of its northerly position and relatively high rainfall, which washes dust from the atmosphere, Galloway forest, at six times the size of greater Glasgow, has become a popular haunt among astronomers. They have been coming in growing numbers looking to enjoy views of the heavens unrivalled in Europe outside Scandinavia or the remote Pyrenees.

In this corner of Scotland even the planets cast shadows of their own, and while, in the middle of a major conurbation, only 200 stars might be visible to the eye, in the centre of the park more than 7,000 can be regularly recorded.

The vast expanse of the Milky Way is routinely observable with the naked eye, stretching as a myriad of light from horizon to horizon. The nearest galaxy to our own, the spiral Andromeda, can also be viewed with a telescope in the right conditions, along with spectacular displays of meteor showers, which are due to climax this season with the arrival this weekend of the Orionids, followed by the Leonids in November and the Geminids the following month.

Keith Muir, head of tourism and environment at Forest Commission Scotland, believes the darkness offers a major tourism opportunity and the chance to get more people out into the park in winter, when the skies are at their clearest and the countryside at its most deserted.

He said the key to getting the status had been convincing a handful of local residents to make minor adjustments to their habits. "This is not about us trying to change the lighting rules in Britain, it is us trying to tell people to put your spotlights down and turn them off when you don't need them. Then you will realise that you have had something amazing overhead all the time," he said.

The IDA will meet in the United States in November to consider Galloway's application alongside that of Hungary's Hortobagy National Park. They are expected to join dark sky parks at the Natural Bridges Monument in south-east Utah, a dark sky community at Flagstaff in Arizona, and the first dark sky reserve at Parc National du Mont Megantic in Quebec. In July this year Borrego Springs in California became the second dark sky park.

In recent decades there has been growing pressure to reduce the glare from street and other lighting from scientists and enthusiasts across the world. Supporters of organisations such as the British Astronomical Society's Campaign for Dark Skies claim that £110m a year is lost in wasted energy from poorly positioned lights.

Street lighting from sodium lamps provided by local authorities remains the biggest polluter in the UK. But apart from spoiling the views, the loss of darkness has been blamed for disrupting migration and breeding patterns of animals. Songbirds have been left confused by the encroaching all-night dawn, while even insect populations are believed to be impacted as they cluster around artificial lights.

Human psychology and physical health is also affected. Artificial light has been found to disrupt sleep patterns and the human internal clock with its circadian rhythms of sleep and wakefulness, while one study suggested a link between breast cancer rates and night-time brightness.

The Bortle scale: Visibility levels

1. Black sky The Milky Way, Scorpius and Sagittarius cast shadows

2. Dark sky Airglow weakly visible near the horizon

3. Rural sky Some light pollution at the horizon

4. Rural/suburban transition Milky Way begins to lose clarity

5. Suburban sky Clouds become brighter than the sky

6. Bright suburban sky The Milky Way is only visible at zenith

7. Suburban/urban transition Sky takes on greyish hue, light sources visible

8. Urban sky Sky glows orange

9/10. Inner city sky Only the moon and planets are visible