A flurry of recent sightings of the Brocken spectre, a spooky weather effect that was in ancient times believed to be a supernatural creature, have made Burley Moor in Wharfedale a surprise mecca for tourists and meteorologists alike. The phenomenon is so creepy it has made many who have witnessed it afraid of their own shadow.

Named after Brocken, the German mountain on which the spectacle was first noted, the spectre is an optical illusion created when a magnified shadow of an observer is cast on to cloud. It often appears on a misty mountain in low light and resembles a huge ghostly figure with a luminous halo of rainbow-coloured rings, which is caused by the diffraction of light.

The mirage is so terrifying it has inspired German folklore. Legend has it a man was walking alone early one morning when a giant glowing figure suddenly loomed over him. Panicked, he jumped off the mountain to his death.

Brocken mountain, part of the Harz range and the highest peak in northern Germany, pulls mist on its slopes up to 300 days a year. While the number of foggy days in Burley is far fewer, there are frequent reports of sightings of the spectre rising from the moors beside the dale.

If you’re not a hiker or anywhere near Burley, you may still get the opportunity to see Brocken spectre. If you look through the window of an aeroplane mid-flight, you can sometimes see the shadow of the aircraft imprinted on the clouds below, encircled by a rainbow.

For such a mirage to form, the plane needs to be sandwiched between the sunshine and clouds at an angle at which you can see the plane’s shadow. If you’re close enough to the clouds, a glowing spectre should materialise.

Finding your own ghoulish shadow on foot can be more difficult. There needs to be a couple of things working in your favour: a sunny early morning and a certain type of fog. This is why the mountains are such a good place to find them.

But Burley Moor is miles from the closest mountain, so what makes the location so popular with spectres? The clue lies in its proximity to Leeds Bradford airport, which is infamous for being shrouded by fog. The UK’s highest hub is only four miles from the moor, which means the mist that frequently delays flights also creates ghostly shadows nearby.

For spectre hunters, one of the great things about Burley Moor is that you do not have to climb far to see one. The village below, Burley Woodhead, is 170 metres above sea level so, if you’re lucky, you can spot a Brocken ghoul from there.

To give yourself the best chance of seeing one, you need to position yourself between the sun and mist. Ideally, you need to be walking along some kind of an edge, such as a cliff or mountain ridge.

Luckily, Burley Moor has the perfect edge at the perfect angle. A cauldron of mist often bubbles just over the edge and the rays from the early sun hit you from behind as you look over the rim for your shadow. Wait and watch the ebb and flow of billowing cloud beneath you. With luck, it will rise to a point where you are projected on to it with elongated legs and a shrunken head. If you’re there with someone else, you won’t be able to see their spectre but if you stand close enough you will both fit inside one.

To get there, take the Dales Way from Burley Woodhead and head straight uphill. If you’ve timed your day well, walk over towards the righthand edge, keeping an eye on where your shadow is falling. Early morning is best as your shadow is longer and has more chance of falling on to the cloud below.

If you see some mist in the valley but it has not reached your level, go for a walk to give it a little time to build – sometimes it can take until 10am for it to roll on to the hillside. The fog can almost look tidal, pushing in and retreating in waves.

Walking along the edge of Burley Moor towards Ilkley Moor provides plenty of stunning views and more vantage points for Brocken spectres to appear. It’s not an exact science – some forecasts sound promising and may predict a blanket of pre-dawn mist. However, while walking up the hillside, you can suddenly find it is too windy and the fog dissipates, scuppering your chances of seeing a spectre. Nonetheless, it’s well worth the trip for a chance to witness the spookiest trick of the light you may ever encounter.