The Isle of Sark draws its fair share of visitors in the warm months of summer. The rock is a haven for rare wildlife, a landscape where pretty hedgerows and quaint villages are bordered by a breathtaking, craggy coastline. There is plenty to do. The events calendar is full with wildflower walks, scarecrow competitions and sheep races that last a weekend.

Today, the inhabitants of Sark, the smallest of the four main Channel Islands, celebrate a unique addition to their list of attractions, one they hope will bring more visitors in the cold, dark winter season. Lying 80 miles off the south coast of England, Sark has been declared the first "dark sky island" in the world.

The award is in recognition of the exceptional blackness of the night sky that makes for spectacular stargazing on the island. On a cloud-free night, countless stars and hurtling meteors are visible against a backdrop of the Milky Way that reaches across the sky from one horizon to the other.

The announcement, by the International Dark Sky Association (IDA), a US-based organisation devoted to preserving the darkest and most beautiful night skies on Earth, follows more than a year of work with the island's 600-strong community to ensure as little light as possible spills upwards into the sky, where it can blot out starlight.

"You get spectacular views from lots of places in the UK, but there are few very special sites that are world class in terms of how dark they are," said Steve Owens, an astronomer who led Sark's application to the IDA.

"If you go to a place like Sark, the Milky Way is a regular feature of the night sky. It always fills me with a sense of wonder. Each of those dots is a sun and there are 100 billion of them. It makes me appreciate how special Earth is. We've not found anywhere else in the cosmos that is a perfect haven for life."

To earn the title of dark sky island, officials on Sark measured night time illumination levels and submitted digital photographs that showed the clarity of constellations in the night sky. As part of a lighting audit, Owens visited every outside light on the isle, which covers 5.5 sq km (2 sq miles), and made recommendations to reduce the amount of light escaping from them into the sky.

The Isle of Sark was already a dark place at night. There are no public streetlights and few, if any, buildings are floodlit. The favoured night time accessory for locals is a head torch. All cars are banned from the island. The only motor vehicles allowed on Sark are tractors, which tow trailers of supplies from the harbours and, in emergencies, pull the island's fire engine and ambulances, which have had their engines removed to make them lighter.

The government of Sark, the Chief Pleas, welcomed the award as recognition of the island's environmental credentials and as a potential boost for its economy.

"Our tourism is geared towards sunny weather, but this might bring people over in their woolly jumpers in the winter months when we have some wonderful night skies," said Paul Williams, chairman of the island's agriculture committee, whose other hats include that of volunteer firefighter and special constable. "Astronomy is catching on and lots of people want to know about the stars and planets, and whether there is life out there. Who knows, maybe they'll spot something from Sark," he told the Guardian.

The self-governing island is usually reached by boat from Guernsey, though services run from Jersey and France. The award of dark sky status ranks among the island's more notable events since an unemployed French nuclear physicist arrived in 1990 with a handgun and declared plans to take the island by force the following day. He was arrested and sent home when two volunteer police officers found him sat on a bench at a village church.

Sark joins a select group of dark sky regions around the world, including Galloway forest park in southern Scotland, which became Europe's first dark sky park in 2009. Keith Muir, head of tourism at the park, said the award prompted an upsurge in interest in astronomy and the night sky. Local hotels and B&Bs have started running stargazing nights and neighbouring councils have brought in dark sky policies to reduce their own light pollution. A new observatory is planned for the edge of Galloway Forest Park that will hold lectures and house a public telescope.

"The interest has grown and grown. We've even had requests from people to come up and renew their marriage vows under the stars. A lot of people don't realise how dark it is and go home early because they get scared shitless," Muir said. In the northern hemisphere, the darkest skies are visible between September and April, and for two hours after sunset.

Efforts to preserve areas where lighting has yet to spoil views of the night sky follows work by the Campaign for Dark Skies, a British group set up in 1989 to highlight the growing problem of light pollution. From an urban street, it might be possible to see between 50 and 100 stars, but from a truly dark spot there are too many to count.

Roger Davies, the president of the Royal Astronomical Society, said the announcement was a great achievement for Sark. "People around the world are becoming increasingly fascinated by astronomy as we discover more about our universe, and the creation of the world's first dark sky island in the British Isles can only help to increase that appetite. I hope this leads to many more people experiencing the wonders of a truly dark sky."

Other UK parks are now working towards dark sky status, including Exmoor national park, Loch Lomond and the Trossachs national park, and the Peak District national park.