Before dawn this weekend – May 5 and 6, 2018 – the Eta Aquariid meteor shower reaches its annual peak. Here’s the bad news. A bright moon will interfere with meteor-watching. Here’s the good news. There are some tricks to watching in moonlight. More good news if you live south of the equator … this shower particularly favors the Southern Hemisphere.
It’s true. The moon will be out in force during the prime viewing hours of this predawn meteor shower in 2018. To optimize your chances for seeing meteors, try one or both of these two things. First, try watching in a dark country sky in very late evening, or around midnight, when the moon is either still below the horizon, or low in the sky. You won’t catch as many meteors, but you might catch a few. Don’t know when the moon rises in your sky? Find out with this handy custom sunrise-sunset calendar.
Second, if you’re watching in the prime hours before dawn – when the Eta Aquariid radiant point is highest in your sky, and the most meteors will be flying – try sitting in a moonshadow. That could be the shadow of a barn or large solitary tree or even a mountain, anyplace you can create some extra darkness for yourself while gazing up at an open sky.
It’s hard to say with certainty whether May 5 or May 6 will be the better morning to watch. This shower has a relatively broad peak. Try both mornings. Just remember that – as seen from all parts of Earth – the dark hour before dawn typically presents the greatest number of Eta Aquariid meteors.
And, as always for meteor-watching, be sure to avoid city lights …
Under ideal conditions, the Eta Aquariid meteor shower produces up to 20 to 40 meteors per hour. If you’re in the Southern Hemisphere, and you have a very dark sky with no moon, you might see that many in a year when the moon is not in the sky. In the Northern Hemisphere, those living at subtropical and tropical latitudes have the advantage over their more northern counterparts.
North of about 40 degrees north latitude the meteors tend to be sparser. The reason has to do with the time of twilight and sunrise on the various parts of Earth. To learn more, check this post on why more Eta Aquariid meteors are visible in the Southern Hemisphere.
Bottom line: In 2018, the Eta Aquariid meteor produces the most meteors before dawn on May 5 and 6 in the glare of a bright waning gibbous moon.
Bruce McClure has served as lead writer for EarthSky's popular Tonight pages since 2004. He's a sundial aficionado, whose love for the heavens has taken him to Lake Titicaca in Bolivia and sailing in the North Atlantic, where he earned his celestial navigation certificate through the School of Ocean Sailing and Navigation. He also writes and hosts public astronomy programs and planetarium programs in and around his home in upstate New York.