The annual Eta Aquariid meteor shower peaks this weekend, and people will inevitably ask about its radiant point. That’s point in the sky from which meteors in annual showers appear to radiate.
You don’t have to locate the radiant to watch the Eta Aquariid meteors. Instead, the meteors will appear unexpectedly in all parts of the sky. Yet if you traced their paths backwards, all of these meteors would appear to radiate from a single point in our sky, from a Y-shaped group of stars – an asterism – called the Water Jar in the constellation Aquarius.
Aquarius is faint. You’ll need a dark sky to spot it. The bright star Fomalhaut in the constellation Pisces Austrinus, the Southern Fish, is near it and can guide your eye. On old star charts, the Aquarius the Water Carrier is often pictured pouring water into the open mouth of the Southern Fish, from the Water Jar. In a very dark sky, you can see a zigzag line of star leading downward from the Water Jar to the star Fomalhaut.
Or try star-hopping to the Water Jar from the Great Square of Pegasus (see star chart below). Four medium-bright stars mark the corners of the Square. Looking eastward in the hour or two before sunup in May, the Great Square of Pegasus glitters like a celestial baseball diamond. Imagine the bottom star as home base. Draw a line from the third base star through the first base star, then go twice that distance to locate the star Sadal Melik in Aquarius.
To the lower left of Sadal Melik is the small Y-shaped Water Jar, marking the approximate radiant of the Eta Aquariid meteor shower.
Bottom line: Eta Aquariid meteors radiate from the Water Jar in the constellation Aquarius. Just remember, you don’t need to know the shower’s radiant point to watch the meteors!
Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.