Perseids are peaking this weekend!

The composite image above – from John Ashley at Glacier National Park in Montana, in 2016 – perfectly captures the feeling of standing outside as dawn is approaching, after a peak night of Perseid meteor-watching. As viewed from anywhere in the Northern Hemisphere, the Perseids’ radiant point is highest at dawn, and so the meteors rain down from overhead. View the full image here.

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When is the peak of the Perseid meteor shower in 2018? The best mornings will likely be August 12 and 13. The morning of August 11 is worth trying, too, as the Perseids are known to rise gradually to their peak. The best news is, in 2018, the moon is gone from the night sky! The peak may bring 50 to 60 – or more – meteors per hour, assuming you’ve given yourself optimum conditions for meteor-watching.

Those optimum conditions are simple to attain. Go to a country location, far from city lights. And watch during the hours between late evening (around midnight) and dawn.

Can’t get out of town? Then go to the darkest sky you can find near you (a beach? a park?) as late at night as you can. Situate yourself in the shadow of a tree or building, if there are lights around. Look up, and hope for the best! Who knows … you might catch a shooting star.

The fact is, this weekend is wonderful for meteor-watching. Enjoy it! We won’t have such gloriously moon-free nights for the Perseids again until 2021.

The Perseids are a long-lasting shower, starting each year around mid-July. People have caught a few already in 2018. Eliot Herman in Tucson, Arizona, captured this early Perseid on August 4. Nikon D810 camera and a 8 mm Sigma fisheye @ 15 sec, ISO 3200.

Can you watch the shower in the evening hours? From the Northern Hemisphere, you might see a smattering of Perseid meteors in the evening (assuming you’re watching in a dark sky). Plus, mid-evening is the best time of night to try to catch an earthgrazer, which is an elongated, long-lasting meteor that travels horizontally across the sky. Earthgrazers are rare but most memorable if you’re lucky enough to spot one.

What if you’re in the Southern Hemisphere? From the Southern Hemisphere, the first meteors – and possible earthgrazers – won’t be flying until midnight or the wee hours of the morning.

In either the Northern or the Southern Hemisphere, the greatest number of meteors streak the sky in the few hours before dawn.

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The earliest historical account of Perseid activity comes from a Chinese record in 36 A.D., where it was said that:

… more than 100 meteors flew in the morning.

Numerous references to the August Perseids appear in Chinese, Japanese and Korean records throughout the 8th, 9th, 10th and 11th centuries. Meanwhile, according to ancient western skylore, the Perseid shower commemorates the time when the god Zeus visited the mortal maiden Danae in the form of a shower of gold. Zeus and Danae became the parents of Perseus the Hero – from whose constellation the Perseid meteors radiate. More about the Perseid’s radiant point below.

The Perseid meteors happen around this time every year, as Earth in its orbit crosses the orbital path of Comet Swift-Tuttle. Dusty debris left behind by this comet smashes into Earth’s upper atmosphere, lighting up the nighttime as fiery Perseid meteors. The meteors start out slowly in the evening hours, begin to pick up steam after midnight and put out the greatest numbers in the dark hours before dawn.

The parent comet of the Perseids – Comet Swift-Tuttle – takes about 130 years to orbit the sun once. We see the meteor shower when Earth intersects the comet’s orbit each year, and debris left behind in its orbit enters our atmosphere. Chart via Guy Ottewell. More awesome Perseid charts from Guy in this post.

The paths of the Perseid meteors, when traced backward, appear to originate in the constellation Perseus. Hence, this meteor shower’s name. While out there peering into dark skies, try looking for the Perseid’s radiant point. You don’t need to find it to enjoy the meteors, but it’s fun to find.

Perseus itself isn’t all that easy to find, but a nearby constellation – Cassiopeia the Queen – is. Look northward for Cassiopeia. It has a very distinctive shape of the letter W or the number 3. See it? Good.

The constellation Perseus, radiant for the annual Perseid meteor shower

The constellation Perseus, radiant for the annual Perseid meteor shower. The easy-to-spot constellation Cassiopeia is nearby.

Want to go deeper? Then look for the Double Cluster in Perseus. This dual cluster of stars almost exactly marks the radiant point of the Perseid meteor shower. You can find it by scanning with your binoculars between Perseus and Cassiopeia.

Although the Double Cluster can be seen with the unaided eye in a dark country sky, the Double Clusters’ stars burst into view through binoculars. The clusters are more formally known as NGC 884 (Chi Persei) and NGC 869 (h Persei). The Double Cluster is thought to be over 7,000 light-years away from us, in the Perseus arm of the Milky Way galaxy.

Double cluster in Perseus via Greg Hogan of Kathleen, Georgia.

Now here’s the good news. You don’t need to know the constellation Perseus to watch the Perseid meteor shower. You don’t need to find the radiant point. The Perseids do radiate from there, but they will appear in all parts of a dark night sky.

Here’s all you do need to know about the radiant point. As viewed from the Northern Hemisphere, the radiant sits low in the northeast sky at evening and climbs upward throughout the night. The higher that the radiant is in your sky, the more Perseid meteors you’re likely to see. For the Perseids, the radiant is highest before dawn.

The Perseid meteors are even visible in the Southern Hemisphere, although the numbers are not as high. Photo credit: ESO/S. Guisard

Some Perseid meteors will be visible in the Southern Hemisphere, although the numbers will not be as high. Photo via the European Southern Observatory/S. Guisard in northern Chile.

Bottom line: The mornings of August 11 and 12 are both fine for meteor-watching in 2018, providing you have a clear sky.

Moonless nights for the Perseids (great charts in this post!)

Looking for a dark area to observe from? Check out EarthSky’s interactive, worldwide Best Places to Stargaze map.

EarthSky’s meteor shower guide for 2018

Bruce McClure