• The best times to look for eta Aquarid meteors are just before local dawn on May 5th and 6th.
• Southern-hemishpere observers are favored; they could see as many as 40 or 50 shooting stars per hour.
• Eta Aquarid meteoroids hit Earth's atmosphere traveling 66 km/s.
• Typical eta Aquarid meteors are as bright as a 3rd magnitude star.

Our planet passes close to the orbit of Halley's comet twice a year. Although the comet itself is very far away [diagram] tiny pieces of Halley are still moving through the inner solar system. They're leftovers from the comet's many close encounters with the Sun. Each time Halley returns (every 76 years) solar heating evaporates about 6 meters of ice and rock from its nucleus! Debris particles called meteoroids, usually no bigger than grains of sand, gradually spread along the comet's orbit forming an elongated stream of space dust. Earth passes through the debris stream once in May (the eta Aquarid meteor shower) and again in October (the Orionid meteor shower).

The eta Aquarids are named after a star in the constellation Aquarius. The star has nothing to do with the meteor shower except that the shower's radiant happens to lie nearby. (The radiant of a meteor shower is a point in the sky from which the meteors appear to stream.) The eta Aquarid's sister shower in October is called the Orionids, after the constellation Orion.

The eta Aquarid radiant never climbs very far above the horizon in the northern hemisphere. That makes it a better shower south of the equator. Most years when bright moonlight is not a problem northerners count about 10 eta Aquarid meteors per hour, while southerners see 6 or 7 times that many.

Northern sky watchers sometimes spot spectacular "Earth grazers," while the active eta Aquarid radiant is low on the horizon. These are meteors that skim horizontally through the upper atmosphere. "Earth grazers" are typically slow and dramatic, streaking far across the sky.

Middle-latitude sky watchers in both hemispheres will see the eta Aquarid radiant rise over the eastern horizon at approximately 2:30 a.m. local time. Aquarius is a fairly dim constellation. The nearest bright star is 1st magnitude Fomalhaut in the constellation Piscis Austrini. Fomalhaut is a good finder star for sky watchers in the south, but it's not much use to northerners because of its low altitude. In Sydney, Australia, Fomalhaut will be visible at 4 a.m. at an elevation of +25 degrees, just above and westward of the shower's radiant.

Above: This image shows the area of sky around the eta Aquarid radiant (indicated by a red dot) as seen from Sydney, Australia at 4 a.m. on May 5th. At 4 a.m. local time -- that is to say, when it is 4 in the morning where you live -- the following statements will be true: The radiant will be about 30 degrees above the eastern horizon if you live at a mid-latitude site south of the equator. The radiant will be about 15 degrees above the eastern horizon if you live at a mid-latitude site north of the equator. Northern observers should rotate this sky map by 180 degrees to see the arrangement of stars in their hemisphere.

Experienced meteor watchers suggest the following viewing strategy: Dress warmly. Bring a reclining chair, or spread a thick blanket over a flat spot of ground. Lie down and look up somewhat toward the east. Meteors can appear in any part of the sky, although their trails will tend to point back toward the radiant.