What are the Eta Aquariids?

Origin story

The Eta Aquariids are leftover bits of debris from the famous Comet 1P/Halley. The meteor shower is active each year between April 19 and May 28, and peaks in early May. Comet Halley circles the Solar System every 76 years; the comet’s orbit was first predicted in 1705 by Edmund Halley, but Comet Halley has been observed in the sky for centuries. One famous visit happened in 1066 around the time of the Norman Conquest in England, and is featured on the Bayeux Tapestry that records the key Battle of Hastings during the conquest.

See Brian Ventrudo’s Exploring the Night Sky for more on the 2020 meteor shower

The radiant

Eta Aquariids’ radiant, located in Aquarius (Stellarium)

Meteor showers appear to originate in one region of the sky, called the radiant. In this case, the radiant is the constellation Aquarius (the Water Bearer). To find Aquarius, look for the “great square” of Pegasus, then move southeast. While Aquarius is faint, that’s about where the meteor shower radiant is located. The Eta Aquariids are named after one of the brightest star in Aquarius, called Eta Aquarii. Eta Aquarii is one of four stars that make up the “water jar” asterism in Aquarius.

What makes the meteors unique

Eta Aquariid Meteor Shower, photographed at the Marshall Space Flight Center May 5, 2015. (MSFC Meteoroid Environment Office)

Astronomers consider the Eta Aquariids “fast” meteors, which whiz through the upper atmosphere at 66 kilometres a second and tend to leave a train of debris behind. While the overall average of the meteor shower is low, at peak times you can see as many as 30 meteors an hour, with some of their trails lingering in the sky for several seconds.

Observing tips

You can see the meteor shower in both the Northern and Southern hemispheres, though they are easier to see from southern latitudes. All you need is your eyes — no binoculars or telescope are necessary. If possible, try to pick a time when the Moon is either below the horizon or at a crescent phase; the Full Moon can wash out the light of the meteors. Get up early, sometime between 2 a.m. and dawn. Find a spot as far away from outdoor lights as you can, face east, and give yourself 20 minutes to adjust to the darkness. Dress warmly, get comfortable on a blanket or a lawn chair, and wait patiently as an average of 10 to 20 Eta Aquariid meteors per hour streak across the sky.