The Eta Aquariids reach peak activity over the next few nights, providing one of the best meteoric displays for the southern hemisphere and a special treat for observers in the northern hemisphere. The activity graph below is updated every 15 minutes – click for details.
What are the Eta Aquariids?
The period May 4 – 8 sees the peak of activity of the Eta Aquariid meteor shower. This is the strongest meteor shower of the south celestial hemisphere and is also best observed from the southern hemisphere. The shower is caused by meteoroids (small crumbs) of the most famous of all periodic comets – 1P/Halley. This shower’s radiant, the apparent point where the meteors fly out or radiate from (hence the name) is in constellation Aquarius. More precisely the radiant is located close to the conspicuous ”Mercedes” asterism of four 3rd magnitude stars. While Eta Aquariids can appear anywhere in the sky, tracing their paths backwards will intersect the radiant. At 66 km/s the Eta Aquariids are very fast meteors which often leave persistent trains.
How and where can I see them?
Being a southern hemisphere meteor shower the Eta Aquariids are best seen from the southern hemisphere. The radiant rises in the morning, so only in the final two hours or so before dawn will any Eta Aquariids be visible. Evening and midnight hours will be devoid of Eta Aquariids. The shower’s peak ZHR (Zenithal Hourly Rate) is somewhat variable, ranging from 50 to 80 meteors per hour. In 2013, however, there was a significant activity outburst as the ZHR reached approximately 130 meteors per hour with a high proportion of bright meteors.
Higher northern latitudes will see low activity from the Eta Aquariids as the radiant never rises high above the horizon. However, active meteor showers with their radiant near the horizon provide a special visual treat for observers – the so-called “Earth grazers”. These are meteors that strike our atmosphere nearly tangentially, skimming its higher parts. Such meteors are exceptionally long, stretching halfway or nearly across the entire sky and lasting for several seconds. While only a few of these will be visible when the radiant is low, each will be spectacular! Good luck with your observations!
To observe the Eta Aquariids, you need to dress warm, bring a reclining chair and watch the sky. You need no other equipment. If you decide to do so, use the IMO major meteor shower observing technique. This way your data will be in a standard format, that can readily be used for analysis. Send us your data as soon after the observations as posssible.
The 2013 outburst
The 2013 outburst of the Eta Aquariids was caused by several old dust trails the Earth encountered. Mikiya Sato posted a warning for observers on “meteorobs” mailing list two days before the peak about the possible increase in activity. The Earth encountered dust trails released in 1197 and 970 BC with additional meteoroids from 1403, 1333, 1265, 1128, 985 and 835 BC. No predictions are available for 2014 at this time.