Meteor showers Eta Aquariids
Eta Aquariids
One of two letters Halley sends every year
Fast meteors from Halley’s dust, far better placed for the southern hemisphere.
- Active period
- 19 April to 28 May
- Usual maximum
- Around 6 May
- ZHR under ideal skies
- About 50, southern hemisphere
01 / Overview
Meet Eta Aquariids
The Eta Aquariid dust comes from comet 1P/Halley. In early May Earth crosses the inbound side of its orbit, and the meteors arrive at about 66 km/s — fast enough that many leave trains lasting several seconds. The radiant sits just south of the celestial equator, so the further south you are, the longer you can watch it.
Why the southern hemisphere has the advantage
The radiant only rises shortly before dawn. At northern mid-latitudes the sky brightens almost as soon as it clears the horizon, leaving a window of roughly an hour; further south there are several dark hours to use. The same shower can yield several times the counted rate at one latitude compared with another.
The same comet’s other shower
In October Earth crosses the other side of Halley’s orbit, producing the Orionids. Both showers run near the upper limit of meteor speed for the same reason: their dust travels the same retrograde orbit.
02 / Key data
Core parameters
- Active period
- 19 April to 28 May
- Usual maximum
- Around 6 May
- ZHR under ideal skies
- About 50, southern hemisphere
- Parent body
- Comet 1P/Halley
- Recurrence
- Early May, every year
Data and calculation notes
Active periods, peak dates and rates are multi-year averages; each year differs a little, so plan against the forecast issued for the year in question.
03 / Observing tips
How to watch
- The two hours before dawn are the only real window, and it widens towards the south.
- The meteors are fast and leave visible trains, which suits long exposures.
- Face an open south-eastern horizon rather than staring at the radiant itself.
04 / Sources