The Eta Eridanids meteor shower
Key facts
- Peak
- around 7 August
- Active
- about 31 July to 19 August
- Rate at peak (ZHR)
- about 3
- Speed
- 64 km/s
- Radiant
- Eridanus (near the star Eta Eridani, close to the border with Cetus)
- Parent body
- Comet C/1852 K1 (Chacornac)
Dates shift slightly from year to year. This year's peak is in the events calendar, and the meteor-shower planner shows how high the radiant climbs from where you live, night by night.
The Eta Eridanids are a fast, faint shower of early August that shares the sky with the rising Perseids. They were brought to light by video observers and confirmed by the detailed orbits that modern camera networks provide.
Discovery. Japanese amateur astronomers running networks of video cameras in the 2000s, using software to detect and measure meteors automatically, found a group of meteors from Eridanus in August with closely matching orbits. The shower was added to the international list and has since been seen by video networks around the world.
The parent comet. The orbits match comet C/1852 K1, found in 1852 by Jean Chacornac, a French astronomer at Marseille who also discovered several asteroids. The comet was seen at only one return and is on a long orbit that will not bring it back for a long time. Its dust stream has outlived the comet's brief visit to our records.
The radiant. The radiant is near Eta Eridani, at the northern end of Eridanus, the long, winding River constellation. It lies just south of Cetus, the Whale, and a little below the celestial equator, so it can be seen from both hemispheres. It rises in the late evening and is best placed in the hours before dawn.
What to expect. Only about three meteors an hour. They are fast, at about 64 kilometres per second, so they are quick streaks, mostly faint. Many observers will never knowingly see one, because Perseids dominate the sky at the same time. The way to tell them apart is direction: Perseids come from the north-east, Eta Eridanids from low in the south-east.
Viewing from the UK. The radiant is low in the south-east before dawn. Early August nights are dark enough for faint meteors in most of Britain.
Viewing worldwide. Tropical and southern observers see the radiant higher, and with fewer Perseids to compete with, they have a better chance of picking out Eta Eridanids.
Viewing tips
- Watch in the two or three hours before dawn, when Eridanus is highest.
- Find the radiant below Cetus, south of the bright star Menkar.
- Separate them from Perseids by direction: these come from the south-east.
- Use video if you can, as most members are faint and quick.
- Observe from further south for a higher radiant and fewer Perseids.