Photo via Fast Company
This weekend offers Atlanta-area residents an uncommon astronomical occurrence: a blue micromoon will reach peak illumination at 4:45 a.m. ET on Sunday, May 31. Despite its name, the phenomenon has nothing to do with the moon's color. Instead, it represents the second full moon within a single calendar month—a distinction that occurs roughly once every 30 months, according to The Old Farmer's Almanac.
The term 'blue moon' has two accepted definitions in the astronomy community. The more common modern definition describes a second full moon appearing within the same calendar month. An alternative astronomical definition refers to the third full moon in a season that typically contains only three lunar cycles. The next seasonal blue moon won't occur until May 20, 2027, making this weekend's event particularly noteworthy for skywatchers.
This specific blue moon carries an additional distinction: it qualifies as a micromoon, occurring when the moon reaches apogee—its farthest point from Earth in its elliptical orbit. While the visual difference is subtle, the micromoon will appear approximately 10 to 15 percent smaller in diameter and slightly dimmer than a standard full moon, according to National Geographic. The distinction remains difficult to detect with the naked eye.
For Atlanta residents planning to observe the phenomenon, clear skies and minimal light pollution offer the best viewing conditions. Those interested in astronomical events should note that a similar double blue moon occurrence won't happen again until 2037, making this weekend's early morning viewing window a rare opportunity in the broader celestial calendar.
