The Daytime Xi Orionids meteor shower
Key facts
- Peak
- around 20 July
- Active
- early to late July
- Rate at peak (ZHR)
- detected by radar; not visible by eye
- Speed
- about 41 km/s
- Radiant
- Orion (near the border with Gemini, 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 Xi Orionids are a July daytime shower whose radiant sits in northern Orion while Orion is hidden in the Sun's glare. They are known only from radar.
The radiant. In July, the Sun is passing from Gemini into Cancer, and the stars of Orion rise in the morning twilight shortly before it. The radiant of this shower lies near Xi Orionis, in the club that Orion raises above his head, only about 25 degrees from the Sun. It is above the horizon almost entirely in daylight.
What we know. The shower is listed in the international catalogue from radar surveys that measure the direction and speed of each meteor. The meteoroids enter at medium-fast speed, about 41 kilometres per second, with a maximum around 20 July. Few radio observers have studied it in detail, and its strength from year to year is uncertain.
The parent. No parent body has been identified.
Daytime and night-time. Several streams show both night-time and daytime faces. The Orionids of October and the Eta Aquariids of May, for example, are two encounters with the same stream of debris from Halley's Comet on either side of Earth's orbit. Whether the Xi Orionids have a night-time partner is not known.
What to expect. Nothing by eye. By radar or radio, a small rise in activity around 20 July, overlapping the start of the strong summer season of the Perseids, Southern Delta Aquariids and Alpha Capricornids.
How to observe. Radio counts through July can show a daytime peak against the slow rise in night-time activity. Separating the Xi Orionids from other showers needs equipment that measures direction, so most amateur counts treat them as part of the general daytime background.
Viewing tips
- Use radio or radar: the radiant is too close to the Sun to watch.
- Compare midday and midnight radio counts through July.
- Expect the night-time summer showers to dominate visual counts.
- Never look towards the Sun when observing near dawn.
- Keep consistent settings so the shower stands out against the background.