A Rare Blue Micromoon Peaks This Weekend-And You Won't See This Combo Again for 40 Years
If you're a serious stargazer, it's time to set those alarms: Sunday morning brings a doubly-rare lunar event you won't see again for decades. Something called a blue micromoon peaks at 4:45 a.m. ET on May 31, though it will look full to the naked eye from Friday night through the following evening. For skywatchers in certain regions, there's an extra treat, transforming the double-rarity into a real triple threat: a brilliant red star named Antares will temporarily vanish as the moon passes directly in front of it.
Why Is This Weekend's Moon Doubly Rare?
This weekend's moon is rare because two unusual things are happening at the same time. First, it's a blue moon. That just means we're getting two full moons in May instead of the usual one. May 1 had the first full moon. May 31 brings the second. A blue moon like this only happens every two to three years.
Second, it's a micromoon. Think of it as the opposite of a supermoon. The moon's orbit around Earth isn't a perfect circle-it's slightly oval-shaped. That means the moon gets closer and farther from us throughout the month. A supermoon happens when the full moon is at its closest point. A micromoon happens when it's at its farthest point. This Sunday, the moon will be 252,360 miles away-further than usual. Because of that extra distance, it will look about 6 percent smaller and 10 percent dimmer than a regular full moon. You probably won't notice the difference, but it's there.
The last time this exact combination happened was August 31, 2023. The next one won't occur until December 31, 2066. So if you miss it this weekend, you've got a 40-year wait.
For viewers in the Southern Hemisphere, the moon puts on an extra trick. In Argentina, Chile, New Zealand, eastern Australia, parts of Antarctica, and a few scattered islands, the moon will pass directly in front of a bright red star called Antares. The star will disappear from view for a few minutes as the moon blocks it-then reappear on the other side. It's called an occultation, and it's a spectacular sight if you're in the right place.
If you're anywhere else in the world, you'll still see Antares shining right next to the moon all night long. It won't disappear, but it should still be beautiful.
Despite the name, this blue moon won't appear blue. The term refers only to timing-the occurrence of two full moons in one month. Near the horizon at moonrise and moonset, the moon may glow golden or orange thanks to Earth's atmosphere. Higher in the sky, it returns to its typical bright white.
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How to See the Blue Micromoon
You won't need any special equipment to spot this celestial phenomenon. The moon is normally visible to the naked eye from anywhere with clear skies. As always, find a spot away from city lights for the best view. The moon will rise southeast around sunset and sets southwest before sunrise, reaching its highest point in the southern sky around midnight.
Peak illumination hits 4:45 a.m. ET on May 31. The moon will appear full from the evening of May 30 through the evening of May 31. If you're photographing it, bring a tripod to keep your camera or phone steady. Minimal cloud cover is expected this weekend, so viewing conditions should be excellent across most of the country.
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This story was originally published May 28, 2026 at 10:15 AM.