In 2017, the forecast calls for the greatest number of Eta Aquariid meteors to light up the predawn darkness on May 5 or 6. Despite the waxing gibbous moon lighting up the evening hours and the wee hours after midnight, it still may be a decent year for watching this shower, because the moon sets a few to several hours before sunrise. (Click here, and check the moonrise and moonset box, to know when the moon rises and the sun sets in your sky .) This shower favors the Southern Hemisphere, ranking as one of the finest showers of the year. At mid-northern latitudes, these meteors don’t fall so abundantly, though mid-northern meteor watchers may catch some, too, and might be lucky enough to catch an earthgrazer – a bright, looong-lasting meteor that travels horizontally across the sky – before dawn. The Eta Aquariids are mainly a predawn shower. Follow the links below to learn more about the Eta Aquariid meteor shower.
When and how should I watch the Eta Aquariids? The 2017 Eta Aquariid meteor shower is expected to produce the greatest number of meteors in the wee hours before dawn on May 5 and 6. However, the broad peak of the Eta Aquariid shower may present a decent showing of meteors during the predawn hours on May 4 and May 7, too.
The best time to watch these fast and often bright meteors is in the early morning hours, before the onset of morning twilight. Don’t know when twilight begins in your part of the world? Try one of the links on our almanac page.
Give yourself at least an hour of viewing time for watching any meteor shower. Meteors tend to come in spurts that are interspersed by lulls. Also, it can take as long as 20 minutes for your eyes to adapt to the dark.
You need no special equipment to watch a meteor shower, but a little luck always helps. Meteor watching is a lot like fishing. Sometimes you catch a good number of them and sometimes you don’t.
Radiant point of the Eta Aquariid shower If you trace the paths of the Eta Aquarid meteors backward, they all seem to radiate from a certain point in front of the constellation Aquarius the Water Bearer. This point on the sky’s dome is called the radiant of the meteor shower, which nearly aligns with the faint star Eta Aquarii. Hence, the meteor shower is named in honor of this star.
Eta Aquarii is one of the four stars making up the Y-shaped Water Jar asterism in the northern part of Aquarius. If you can find the Water Jar in the constellation Aquarius, you’ve as good as located the radiant point for the Eta Aquarid meteors. However, the alignment of the radiant and the star is coincidental. Eta Aquarii looms some 170 light-years away while the Eta Aquarid meteors burn up about 100 kilometers (60 miles) above the Earth’s surface.
The higher the radiant appears in your sky, the more Eta Aquarid meteors that you’re likely to see. The radiant soars highest in the nighttime sky just before dawn, so that’s why you tend to see the most meteors in the wee morning hours.
But you don’t have to locate the Water Jar, or the radiant of the shower, to enjoy the Eta Aquarids. These meteors fly every which way across the sky, in front of numerous constellations. Find a dark, open sky away from artificial lights, and sprawl out on a reclining lawn chair to comfortably watch the wondrous nighttime attraction.
How many meteors should I expect to see? In a dark sky, especially at more southerly latitudes, the Eta Aquarids can produce up to 20 to 40 meteors per hour. From mid-northern latitudes, you might only see about 10 meteors per hour. Or you might see more.
Halley’s Comet is the source of the Eta Aquariid meteor shower. Every year, our planet Earth crosses the orbital path of Halley’s Comet in late April and May, so bits and pieces from this comet light up the nighttime as Eta Aquarid meteors. This shower is said to be active from April 19 to May 20, although Earth plows most deeply into this stream of comet debris around May 5 or 6.
The comet dust smashes into Earth’s upper atmosphere at nearly 240,000 kilometers (150,000 miles) per hour. Roughly half of these swift-moving meteors leave persistent trains – ionized gas trails that glow for a few seconds after the meteor has passed.
Our planet also crosses the orbital path of Halley’s Comet at the other end of the year, giving rise to the Orionid meteor shower, which is usually at its best in the predawn hours on or near October 21.
Why not see how many Eta Aquarid meteors you’ll catch in the dark hours before dawn on May 5 and 6?
Bottom line: What’s a good shower for the Southern Hemisphere? In 2017, it’s the Eta Aquariid shower on the mornings of May 5 and 6. It’s possible to see some Eta Aquariids in the Northern Hemisphere, too, but the farther south you live in the Northern Hemisphere, the better! How to watch, some history, chart showing radiant point in this post.
Bruce McClure has served as lead writer for EarthSky's popular Tonight pages since 2004. He's a sundial aficionado, whose love for the heavens has taken him to Lake Titicaca in Bolivia and sailing in the North Atlantic, where he earned his celestial navigation certificate through the School of Ocean Sailing and Navigation. He also writes and hosts public astronomy programs and planetarium programs in and around his home in upstate New York.