Why more Eta Aquariid meteors in Southern Hemisphere?

Deep blue sky over desert mountains with many short white streaks and circle around radiant location.
Eta Aquariid meteor shower in 2015 from Chile’s Atacama Desert. Composite image by Yuri Beletsky.

The famous Eta Aquariid meteor shower – one of the year’s major meteor showers – peaks every year in early May. In 2022, the peak centers around May 5. This shower is known to be richer as seen from Earth’s Southern Hemisphere than from the Northern Hemisphere. Why?

Water Jar in the constellation Aquarius

If you traced the paths of Eta Aquariid meteors backward on the sky’s dome, you’d find that these meteors appear to stream from an asterism, or recognizable pattern of stars, known as the Water Jar in the constellation Aquarius.

This spot in the sky is the radiant point of the Eta Aquariid meteor shower. The meteors seem to emanate from the vicinity of the Water Jar, before spreading out and appearing in all parts of the sky.

Star chart of constellation Aquarius with radial purple arrows and water jar labeled.
The radiant point of the Eta Aquariid meteor shower is near the famous Water Jar asterism of the constellation Aquarius.

Water Jar rises about the same time worldwide…

Because the Water Jar is on the celestial equator – an imaginary great circle directly above the Earth’s equator – the radiant of the Eta Aquariid shower rises due east as seen from all over the world. Moreover, the radiant rises at about the same time worldwide, around 1:40 a.m. local time (2:40 a.m. daylight saving time) in early May, around the shower’s typical peak date.

So you’d think the shower would be about the same as seen from around the globe.

…yet the sun rises later in the Southern Hemisphere

But it’s not. The reason it’s not is that sunrise comes later to the Southern Hemisphere (where it’s autumn in May) and earlier to the Northern Hemisphere (where it’s spring in May).

Later sunrise means more dark time to watch meteors. And it also means the radiant point of the Eta Aquariid shower has a chance to climb higher into the predawn sky as seen from more southerly latitudes. That’s why the tropics and southern temperate latitudes tend to see more Eta Aquariid meteors than we do at mid-northern latitudes.

Cruise to a southerly latitude, anyone?

Everything you need to know: Eta Aquariid meteor shower

Many bright white streaks and glowing moon above desert horizon.
Eta Aquariids in 2013 by Colin Legg in Australia.

Bottom line: Everyone around the globe can enjoy the Eta Aquariid meteor shower in early May. Best for the Southern Hemisphere! Peak in 2023 is on or near the morning of May 5.

Read more: EarthSky’s annual meteor shower guide

May 3, 2020

Like what you read?
Subscribe and receive daily news delivered to your inbox.

Your email address will only be used for EarthSky content. Privacy Policy
Thank you! Your submission has been received!
Oops! Something went wrong while submitting the form.

More from 

Bruce McClure

View All