The Epsilon Geminids meteor shower

Key facts

Peak

around 18 October

Active

about 14–27 October

Rate at peak (ZHR)

about 3

Speed

70 km/s

Radiant

Gemini (near the star Mebsuta, Epsilon Geminorum)

Parent body

Possibly comet C/1964 N1 (Ikeya)

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 Epsilon Geminids are a small, very fast shower that runs alongside the Orionids in October. They are easy to overlook, and telling them apart from their famous neighbour is a good test of an observer's skill.

The radiant. The meteors seem to come from near Epsilon Geminorum, also called Mebsuta, a star in the body of the western Twin, Castor. This is only about ten degrees north-east of the Orionid radiant, which lies above Betelgeuse. The two radiants rise together in the late evening and are best placed before dawn.

The parent. A possible parent is comet C/1964 N1 (Ikeya), the first comet found by the Japanese amateur Kaoru Ikeya, who later shared the discovery of the famous sungrazing comet Ikeya–Seki of 1965. Comet Ikeya 1964 is a long-period comet that takes centuries to go round the Sun, on an orbit that brings its dust to Earth almost head on. That explains the shower's high speed. The link has been suggested from orbit comparisons but is not certain.

What to expect. At most about three meteors an hour, peaking around 18 October, a few days before the Orionid maximum. The meteors are among the fastest of any shower, at about 70 kilometres per second, and many leave brief trains. Because Orionids are also very fast, the only reliable way to separate the two is to note carefully where each meteor appears to come from. A meteor that traces back to the Twins rather than to the area above Betelgeuse may be an Epsilon Geminid.

Viewing from the UK. Good. Gemini is high in the east-south-east before dawn in October, and nights are long and dark. Any session for the Orionids will also include Epsilon Geminids.

Viewing worldwide. The radiant is north of the celestial equator but can be seen from most of the world. Southern observers see it lower in the north-east before dawn.

Viewing tips

1. Watch in the hours before dawn, when Gemini and Orion are high in the south-east.
2. Find Castor and Pollux, then look along Castor's body towards Mebsuta.
3. Separate them from Orionids by tracing each meteor back to its source.
4. Expect very fast meteors, often with brief trains.
5. Plot meteors on a chart if you want to count this shower separately.