8 night sky events to see in May, from a blue moon to a Milky Way showstopper
May’s sky features not one but two full moons as well as the dazzling Eta Aquarids meteor shower. Here’s when to look up for the month’s most striking alignments.
The night sky brims with spectacles this May, from a meteor shower and planet-moon conjunctions to not one but two full moons. The month also brings longer windows to better admire the Milky Way core; Northern Hemisphere stargazers can spot that luminous strip from around midnight until the early morning.
Here are eight of the best astronomical sights to catch this May, including timing to snag the best view.
See the full “flower moon”—May 1
May’s full moon is named for the month’s abundance of blossoms. The sphere reaches peak illumination midday on May 1, although the most dramatic time to watch is when it rises and sets. For the best view, catch it at moonrise or moonset, when an optical illusion makes it appear larger and gives it a warm, orange hue.
(The moon is even older than we thought.)
Eta Aquariid meteor shower peaks—May 5-6
The Eta Aquariids are visible from April 19 to May 28, but their activity peaks overnight from May 5 to 6. Known for their fast, bright meteors and lingering trains, the shower can produce up to a few dozen streaks per hour, especially in the Southern Hemisphere. This year’s conditions, a waning gibbous moon will wash out all but the brightest streaks. Still, patient observers under dark skies may catch a few—especially in the pre-dawn hours.
Mars, crescent moon, Saturn appear close together—May 12-13
Head out an hour before sunrise on the mornings of May 12 to 13 to catch an eye-popping alignment in the eastern sky. Mars, Saturn, and the crescent moon will line up almost perfectly just above the east horizon. The trio will appear roughly an hour before sunrise, then climb higher before our bright star ascends.
To see them, look for a viewpoint with unobstructed vistas toward the east horizon—think: a lake or hilltop. While May 12 and 13 provide optimal alignment, you can also catch the trio clustered together in a pyramid shape on May 14, when the moon is a dramatically thin wisp.
New moon for Milky Way viewing—May 16
To catch May’s astronomical showstopper—the Milky Way core—head out around the night of May 16. The new moon will cast no lunar glow. Pair that with a dark sky, such as those you’ll find in many national parks, and the galactic center will shine at its brightest. It’s also the best time to photograph the Milky Way. The core rises around 11 p.m., depending on your coordinates, and it remains visible until the pre-dawn hours.
The new moon is also an ideal time to view distant galaxies via telescopes. Some of the easiest to see include the Whirlpool Galaxy (near the Big Dipper’s handle) and the Sombrero Galaxy (close to the bright star Spica).
Moon-Venus conjunction—May 18
Don’t miss the sunset on the evening of May 18. Just after it, you can watch the crescent moon and Venus, the sky’s brightest planet, appear in a tight pair. The duo will shine above the western horizon and remain visible for roughly 2 hours. Just as the sky darkens, you can also spot Mercury above the west horizon, with Jupiter above the moon-Venus conjunction, too. (Remember: Only point optical aids west once the sun has fully set.)
A rare “blue moon”—May 31
May closes out with an uncommon lunar event: a second full moon in a single calendar month, often called a blue moon. According to NASA, this occurs about once every two to three years. The blue moon name doesn’t mean our neighbor will actually look blue. Instead, just like the early May moon, it could appear yellowish when it’s near the horizon. Moons typically appear blue only when Earth has certain particles, such as volcanic ash, in its atmosphere.
Use Jupiter to find Gemini—All month
Jupiter shines brightly in the western sky all May; it’s also in the perfect position to help you locate the constellation, Gemini, also known as the twins. The planet sits near the constellation’s two brightest stars, Pollux and Castor. While you can also locate Gemini using another night-sky navigational tool, the Big Dipper, Jupiter offers an especially easy visual cue this month.
Jupiter nears Venus—All month
At the beginning of the month, Jupiter and Venus will appear within 40 degrees (or 10 fist widths) from each other above the west horizon. By Memorial Day, they will line up within 14 degrees (just over one fist width). Mercury joins the scene later in the month, becoming easier to see as it moves toward its greatest eastern elongation in mid-June.
