The forecast calls for the greatest number of Eta Aquarid meteors to light up the predawn darkness over the next few mornings, before dawn on May 5 and 6. Best of all, the May 6 new moon will guarantee deliciously dark skies for this year’s Eta Aquarids. It is difficult to say with certainty which morning will be the better of the two – May 5 or 6 – since this shower has a relatively broad peak. But we give the nod to before dawn May 6. Just remember the dark hour before dawn begins to light the sky typically presents the greatest number of Eta Aquarid meteors. The beginning of astronomical twilight closes the curtains on the final hour of complete darkness. Don’t know when astronomical twilight begins in your sky? Find out with this handy custom sunrise-sunset calendar.
Under ideal conditions, the Eta Aquarid meteor shower produces up to 20 to 40 meteors per hour. The shower is best seen in the Southern Hemisphere, but mid-northern latitudes can still catch some meteors, though at reduced numbers. As alluded to earlier, we are extremely fortunate that the May 6 new moon will provide a dark sky for this year’s Eta Aquarid display. Although the more southerly latitudes have the better view of this shower, tropical and subtropical latitudes in the Northern Hemisphere still enjoy a decent view of the annual Eta Aquarid meteors. North of 40o north latitude the meteors tend to be fewer. But no matter where you live worldwide, the greatest number of meteors usually fall in the dark hours just before dawn.
The point in the sky from which meteors in annual showers appear to radiate is called the meteor shower radiant. You don’t have to locate the radiant to watch the Eta Aquarid meteors, but people always ask about them. Although the Eta Aquarid meteors streak all over the sky, they appear to radiate from the Y-shaped group of stars called the Water Jar. The Water Jar is part of the constellation Aquarius.
To star-hop to the Water Jar, first of all find the four stars of the Great Square of Pegasus. (See sky chart at bottom right.) Looking eastward at about 4 a.m. (Daylight Saving Time), the Great Square of Pegasus glitters like a celestial baseball diamond. Imagine the bottom star as home base. Draw a line from the third base star through the first base star, then go twice that distance to locate the star Sadal Melik.
To the lower left of Sadal Melik is the small Y-shaped Water Jar, marking the approximate radiant of the Eta Aquarid meteor shower. Again, you don’t need to know the shower’s radiant point to watch the meteors!
Bottom line: In 2016, the Eta Aquarid meteor shower peaks before dawn on May 5 and 6. May 7 before dawn might be good as well. This is a great shower for the Southern Hemisphere! But mid-northern latitudes may still enjoy a decent sprinkling of meteors, and the moon will be totally out of the way. Watch in a dark sky, and you might catch as many as 20 to 40 per hour. Have fun!