The Daytime Omega Cetids meteor shower
Key facts
- Peak
- around 8–10 May (northern and southern branches)
- Active
- late April to mid-May
- Rate at peak (ZHR)
- weak on radio; not visible by eye
- Speed
- about 39 km/s
- Radiant
- Cetus and Pisces (two radiants close to the Sun in the sky)
- Parent body
- Unknown
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 Daytime Omega Cetids are a pair of weak daytime streams in early May, with northern and southern branches whose radiants lie on either side of the ecliptic, the Sun's path across the sky.
Twin branches. Many meteoroid streams divide into northern and southern branches because the gravity of the planets has spread their orbits into a broad band. Earth meets the two branches at about the same time but from slightly different directions. The Northern Omega Cetids have a radiant in Pisces with a maximum around 8 May, and the Southern Omega Cetids a radiant near the border of Cetus and Pisces with a maximum around 10 May.
Discovery. Both branches were found by radar, which can detect meteors in daylight. Their radiants are within a few tens of degrees of the Sun, so they are above the horizon almost entirely in daytime.
How active are they? Modern radio results are mixed. Some long series of observations have found little or no clear activity from the northern branch in recent years, while the southern branch shows a weak peak. Meteors arrive at medium speed, about 39 kilometres per second.
The parent. No parent body has been identified.
What to expect. Nothing by eye, though tropical observers may catch a rare earthgrazer before dawn. Early May is also the time of the Eta Aquariids, a strong night-time shower whose radiant is in the same part of the morning sky. A long meteor low in the east at dawn in early May is far more likely to be an Eta Aquariid.
How to observe. By radio, comparing counts through late April and May. The Omega Cetids blend with the other spring daytime showers, the Epsilon Arietids, May Arietids and Omicron Cetids, so separating them needs care, and radar that measures directions is the best tool.
Viewing tips
- Use radio detection; the radiants are too close to the Sun to see.
- Remember that early May dawn meteors are usually Eta Aquariids.
- Count radio echoes daily from late April to late May.
- Never look towards the Sun when observing near dawn.
- Note that the two branches peak a couple of days apart.