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Eta Aquariid meteors are richer from the Southern Hemisphere

Eta Aquariid meteors are richer from the Southern Hemisphere

Eta Aquariid: Lines marking constellation with radial arrows near middle of it.
The radiant point of the Eta Aquariid meteor shower is near the star Eta Aquarii in the constellation Aquarius the Water Bearer. The radiant rises in the wee hours after midnight and is still climbing toward its highest point at dawn. That highest point is in the south as viewed from the Northern Hemisphere, and closer to overhead for the Southern Hemisphere. That’s why the Southern Hemisphere sees more meteors (the radiant is higher up), and it’s why – for all of us around the globe – the hours before dawn are best for this shower. However, in 2023, a bright moon will compete with the meteor shower.

The famous Eta Aquariid meteor shower – one of the year’s major meteor showers – peaks every year in early May. In 2023, the peak centers around May 6. 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. See chart at the top of this post.

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.

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. But it’s not.

The sun rises later in the Southern Hemisphere

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

Bottom line: Everyone around the globe can enjoy the Eta Aquariid meteor shower in early May. Best for the Southern Hemisphere! The peak in 2023 is on the morning of May 6.

Read more: EarthSky’s annual meteor shower guide


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