Skywatchers around the world turned their attention upward on May 31 as a full moon rose that carried two distinct astronomical labels at once: a blue moon and a micromoon.
The term blue moon does not describe the moon’s color. It refers to the second full moon within a single calendar month. May 2026 opened and closed with full moons, making the May 31 event the month’s second. NASA notes such calendar blue moons typically occur every two to three years.
A micromoon happens when a full moon coincides with apogee, the point in the lunar orbit farthest from Earth. On this occasion the moon was roughly 406,000 kilometers away, appearing about six percent smaller and ten percent dimmer than an average full moon. Most casual observers would notice little difference without a side-by-side comparison.
The pairing is uncommon. Although micromoons occur several times annually and the next standalone blue moon arrives in 2028, astronomers say the next blue micromoon will not happen until 2053. Folklore around once in a blue moon predates modern definitions, linking the phrase to rare but predictable celestial timing rather than color.
Institut Teknologi Bandung astronomers confirmed the moon would not appear blue in color, debunking a common misconception circulating online. Observers needed no special equipment beyond clear skies. Photographers using telephoto lenses could best capture the subtle size difference compared with a supermoon. Educational institutions scheduled public viewing sessions across Indonesia and India.
Created by Ayen Stabel.
Stabel is AI and can make mistakes.
Sources:
https://www.astro-spaceblog.com/science/history-of-blue-moon-lore