The first meteor shower of the summer may peak in the early hours of Tuesday morning with stargazers hoping to see dozens of shooting stars tearing across the night sky every hour.
Astronomers have debated the origins of the Delta Aquariids meteor shower, with the sungrazing comet 96P/Machholz regarded as the most likely candidate. The four-mile-wide ball of dust, rock and ice takes a little more than five years to complete an orbit around the sun.
The Delta Aquariids are active from mid-July to late August, but the best time for viewing the shower is expected to be in the hour or two after midnight UK on Monday, before the waning crescent moon has risen enough to brighten the sky.
Meteor showers happen when the Earth passes through the stream of dust left behind by a comet. The dust particles are smaller than grains of sand and produce bright streaks of light when they vaporise in the atmosphere.
On a dark, moonless night stargazers can expect to see 15 to 20 shooting stars an hour at the height of the Delta Aquariids. The shower gains its name from Aquarius, with the shooting stars appearing to come from the direction of Delta Aquarii, a bright star in the constellation.
To find Aquarius, astronomers recommend looking for the square of Pegasus in the south eastern sky then looking down towards the horizon and what looks like a bright star, but which is actually Saturn in Aquarius. On locating the right spot, gaze about 45 degrees away for the best chance of spotting the longer meteor streaks.
“The key to enjoying any meteor shower is finding yourself a truly dark sky location,” Prof Catherine Heymans, Scotland’s astronomer royal, told the Guardian.
“To really appreciate this spectacular light show you’ll need to get away from the street lights and out into the countryside if you can. Then it’s just a case of lying face-up on a blanket with a thermos of hot chocolate, watching and waiting for those shooting stars to streak across the sky,” she said.
Of the Delta Aquarii meteors, 5-10% leave persistent trains: glowing streaks of ionised gas that are visible for one or two seconds after the meteor has passed. Because telescopes and binoculars have a narrow field of view, experts recommend viewing with the naked eye after taking time to adjust to the dark.
“Remember, don’t look at your phone,” Heymans said. “Your eyes take more than 10 minutes to get dark-adapted, and even a quick glance at your screen will reset them meaning you might miss something.”
If cloud cover or moonlight intervenes, fear not. The Delta Aquariids rumble on into August when they merge with the more prolific and typically brighter Perseids.
“Unfortunately, summer meteor showers aren’t the best for children as you need to wait until long after the sun has set for the sky to become dark enough to see them,” Heymans said. “But it’s a great event for adults, particularly those looking for an excuse to take a romantic starlit getaway.”
