One of the most beautiful meteor showers peaks this week. Under a clear, dark sky the Eta Aquarids produce up to 60 meteors per hour, one of the best displays of the year. There is just one catch.
Eta Aquarids are crumbs of the most famous comets of them all – Halley’s comet. As the comet rounds the Sun every 76 years, it releases large amounts of small dusty particles. Over centuries and millenia, these dust particles form a stream – called a meteoroid stream. When the Earth passes through the stream in May, dust particles hit our atmosphere and burn up as meteors of the Eta Aquarid meteor shower. Fun fact – the Earth passes through the same meteoroid stream again in October, and then we see comet Halley’s dust as the Orionid meteor shower.
Brilliant fireball shoots down the Milky Way. Note the reflection in the sea. Photo: Marko Korošec.
The Eta Aquarid meteor shower is a fine one. It is active from mid-April to the end of May, with a broad peak around May 6-7. The meteors are swift, shooting through our atmosphere at 66 km/s. They are often colorful and produce persistent trains. Occasionally the Earth encounters clumps of older dust particles that have been shepherded by the gravitational influence of giant planets – and an even more rich meteor shower happens. The last time this happened was in 2013, when sky watchers were treated to a show of up to 100 bright meteors and even brilliant fireballs per hour.
So where’s the catch? Well… the thing is best seen from the southern hemisphere. There. If you are in Australia, New Zealand, South Africa or anywhere else in the southern hemisphere, you will have a fine show. Not so much in the northern hemisphere. BUT! There is still some good show to be seen here, too. Here is how.
If you are north of 50 °N you will not be able to see any Eta Aquarids. Going further south your odds of seeing a good show improve. The southernmost locations in Europe, such as Canary Islands, southern Spain and Portugal, Malta and far southern Greece may still see a good show with up to 20-40 Eta Aquarids in the predawn sky. The Eta Aquarids peak on May 6 at 14h UT, but the peak of the shower is usually prolonged and good rates can be seen one or two nights before and after the peak. The radiant of the Eta Aquarids rises in the final pre-dawn hours: start watching the skies at 2 am and go until dawn. At around 35 °N you will probably see about 10-15 meteors per hour in the final pre-dawn hour. Find a dark spot – light pollution hides most meteors. You need a spot where the Milky Way is readily seen. And bring clothes, lots of them. It will be cold. But worth it!