Night sky lovers are getting a rare celestial double feature at the end of May. On May 31, a blue moon will rise, and this one comes with an extra twist. It’s also a micromoon, meaning the full moon will appear slightly smaller and dimmer because it’s at one of the farthest points from Earth in its orbit. According to the Farmer’s Almanac, the moon will reach peak illumination at 4:45 am ET on Sunday, May 31. However, skywatchers should still be able to enjoy its glow in the days surrounding the event. Despite the name, the moon won’t actually turn blue. According to NASA, a blue moon simply refers to the second full moon in a single calendar month, something that only happens about every two and a half years. The phrase “once in a blue moon” dates back to the 16th century and was once used to describe something considered impossible. This year’s lunar lineup began with May’s Flower Moon earlier in the month. After this rare appearance, the next time that two full moons will share a month again will be in December 2028.