The Eta- Aquariiden ( sometimes called Mai- Aquariiden ) are a meteor stream, which can be seen in May every year. They come from the famous Halley 's Comet. For at least two millennia sightings are detected this comet. The name " Aquariiden " comes from the Latin name of the constellation Aquarius.
The Eta- Aquariiden are observable from Central Europe only in the last hour before dawn. Since then his Radiant - near the star Eta Aquarii - reached only a small height above the horizon, the meteors of the Eta- Aquariiden have a flat entry angle into the atmosphere, causing the meteor orbits in the sky often appear remarkably long. At a Radiantenhöhe 10 degrees less than 20 percent of the meteor be visible in comparison to the zenith position, that from a ZHR of 65, the observer can actually see maximum current 10-15 meteors per hour. Further south, the conditions improved appreciably, because both the duration of the night and the amount of radians in the possible observation window to grow. For example, in the Canary Islands you can effectively use about three hours and the Radiant reached the end of more than 30 degrees altitude.
On May 6, 2013, maximum ZHR of 135 was observed. According to model calculations of Mikiya Sato activity goes back primarily to meteoroids during the Perihelpassage the comet 1P/Halley 1197 BCE and 910 v.u.Z. were released and came close to Earth this time.