It is time for stargazers to dig out the deckchairs to try to enjoy what is considered to be one of the best meteor showers of the year.
The Perseids are expected to peak on the night of 12 August, although they have been active from mid-July and will continue to be visible for a further couple of weeks.
The annual event, which is most visible in the northern hemisphere, arises as comet debris burns up in Earth’s atmosphere.
“Each year, Earth passes through the material shed by an ancient celestial body, Comet 109P/Swift-Tuttle, which is estimated to be well over 5bn years old – older even than Earth,” said Dr Richard Parker, an astrophysicist at the University of Sheffield.
He said the comet visited the inner solar system every 133 years, and would next make its closest approach to Earth in 2126.
“Notably, the comet is the largest object that approaches Earth – but thankfully, it’s not predicted to come dangerously close for thousands of years,” Parker added.
The Perseids arise because debris left by the comet lingers in space.
“Because we orbit the Sun year after year, we keep hitting into it at the same time and from the same orientation,” said Dr Ed Bloomer, an astronomer at the Royal Observatory, Greenwich. “So from our point of view, standing on the Earth, it looks as if [the Perseids] come from that same part of the sky every single year.”
This radiant appears to be in the constellation of Perseus – giving the meteor shower its name.
Perseus is now visible in the north-eastern sky. But for the best chance of seeing the meteors, Bloomer said it was worth turning towards the east-south-east, looking towards Saturn, or more to the north, looking towards the constellation of Ursa Major.
“To maximise your chances, if you turn slightly away from Perseus, you’re likely to catch them out the corner of your eye,” he said, noting that it was easier to see in low light conditions with peripheral vision.
With the peak occurring just days after a full moon, experts have said fainter meteors might be tricky to see this year.
Bloomer said it was best to head out late at night to as dark a location as possible, with as clear a horizon as possible, and wait up to 30 minutes for your eyes to adjust.
He recommended viewing with friends, but said individual meteors might flare up for only a second, or even less.
“It’s one of those things where you can’t really spot it, turn to somebody beside you, tap them on the shoulder and try and get them to look at the same part of the sky. It’s done by then,” he said. “So in a way, it is quite a solitary thing, because you just have to sit and have your eyes open and that’s it.”
