Look for ‘Earthgrazers’ as the Eta Aquarid meteor shower overlaps the new moon on May 19

The peak of the Eta Aquarid meteor shower is a few days behind us, having occurred just before daybreak on Saturday morning (May 6).

This meteor display is active in the first week of May but will continue to put on a show for patient observers through May 28. The Eta Aquarid meteor shower is known to produce long streaks whose paths are aimed away from the “Water Jar” asterism of Aquarius. Their streaks are long for a good reason, for which I will explain in a moment.

Even though this year isn’t a particularly great year for viewing the Eta Aquarids, there’s still a chance for skywatchers to luck out and catch a sight of a long “Earthgrazer” created by a fragment of Halley’s Comet burning up along a shallow path through Earth’s atmosphere.

Related: Meteor showers 2023: Where, when and how to see them

Moon is a major handicap

To curb your enthusiasm, I feel it necessary to also warn you that this year, the Eta Aquarids will be poorly seen, because of glare from a practically full moon throughout the first weeks of May (it turned full on May 5 the day prior to its peak). Like a dazzling celestial spotlight glaring amidst the stars of Libra the Scales, our nearest neighbor in space will serve to light up the morning sky and likely squelch the majority of the fainter streaks from being visible.

In more favorable years — without a bright moon — the Eta Aquarids are usually the richest meteor display for observers situated south of the equator, producing up to 60 meteors per hour.

But with a new moon occurring on May 19, skywatchers should still be able to see a few stragglers toward the end of this annual meteor shower.

Too low

But bright moonlight is only one of two obstacles in viewing this shower. The other problem is that if you live in the Northern Hemisphere, hourly meteor rates drop off rather rapidly. This is especially true for north temperate latitudes because the Eta Aquarid radiant — from where the meteors appear to dart from — never reaches a high enough altitude above the southeast horizon (it rises around 3 a.m. local daylight time); so, rates are correspondingly low.

Observers typically report only 10 meteors per hour at 26 degrees north latitude (Miami), half this at 35 degrees latitude (Chattanooga) and little or nothing at all is usually seen north of latitude 40 degrees (Denver).

Hope for a “grazer”

Still, even if you live in a far northern location there is still reason to head outside and take a look, for it is possible that you just might luck out and sight an “Earthgrazer.” These are meteors emerging from the Aquarid radiant that will skim the atmosphere horizontally — much like a bug skimming the side window of an automobile. They also sometimes leave colorful, long-lasting trails.

Remember earlier when I said that the Aquarid trails are long? Well, Earthgrazing meteors tend to be extremely long and usually appear to hug the horizon rather than shooting overhead where most cameras are aimed. They also tend to be quite bright and can attract attention even in bright moonlight. They are rarely numerous, but even if you only see just one or two, they’ll likely be memorable.

Halley’s legacy

And if for nothing else, be aware that if you catch sight of an Aquarid meteor, you will have seen a piece of space debris that was likely shed by the famous Halley’s Comet many centuries ago. They remain traveling more or less along the comet’s 75-year orbit around the sun.

These particles likely range in size from sand grains to pebbles, and they have the consistency of cigar ash. Earth, in its annual orbit around the sun passes through this thin “river of rubble” twice. Once in late October, producing the annual Orionid meteor shower and also in early May causing the Eta Aquarids. Each meteoroid collides with Earth’s upper atmosphere at 41 miles (66 km) per second, creating an incandescent trail of shocked, ionized air. This hot trail, not the tiny meteoroid itself, is what you ultimately see streaking across the sky.

And just in case you’re wondering, Halley’s Comet itself will return to the sun’s vicinity during mid-summer of 2061.

If you want to get a closer look at Aquarius to hopefully see some of the Eta Aquarids, our guides to the best telescopes and best binoculars are a great place to start.

And you’re looking to snap photos of the night sky in general, check out our guide on how to photograph meteors and meteor showers, as well as our best cameras for astrophotography and best lenses for astrophotography.

Joe Rao serves as an instructor and guest lecturer at New York’s Hayden Planetarium (opens in new tab). He writes about astronomy for Natural History magazine (opens in new tab), the Farmers’ Almanac (opens in new tab) and other publications. Follow us on Twitter @Spacedotcom (opens in new tab) and on Facebook (opens in new tab).