The Eta Aquarid meteors, fragments of Halley’s Comet, should be seen on May 5, with a peak around 21h by Universal Time. That is, by clocks now twisted forward to so-called “daylight-saving time,” 8 PM in Britain, and 5 or more hours earlier in North America.
The shower gets its name because its radiant – the point from which the meteors fly out to any part of the sky – is near Eta Aquarii, one of the stars forming a distinctive small triangle, sometimes called the Urn or Water-Jar of the constellation Aquarius the water-carrier. The radiant does not come up into view until after midnight, so we will be seeing the shower some hours after its probable peak.
Here is the scene for an American location as the radiant climbs from the eastern horizon. Each hour, it will slope up higher, parallel to the celestial equator, so that more of the meteor streaks will be above the horizon.
When you look toward this radiant, you are looking into the meteor stream on its way out across Earth’s orbit. This explains why the meteors hit the front or morning side of Earth and why you see them mostly in the hours between midnight and morning twilight. (Notice the point we mark as “Earth’s direction of motion.”) This is explained more richly, with a space diagram, in our web page on “Halley meteors.”
How many might you see? The zenithal hourly rate (ZHR) of the Eta Aquarids is given as 50 – better than all except the Quadrantids (January), Perseids (August), and Geminids (December). But this is the estimated number that a single alert observer might count if the sky is clear and dark and the radiant is overhead. For your actual location and sky conditions your likely count may be in the single digits.
Another factor it the Moon. This May 5, it will be near first quarter phase and the light from its bright crescent will not begin to invade the eastern sky until around 6 in the morning.
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