The second full moon of May—a so-called Blue Moon—will occult the ancient red supergiant star Antares on May 31, creating a dramatic celestial event for observers in the right locations. Occultations occur when the moon passes directly in front of a more distant object, briefly hiding it from view.
Antares, a massive star roughly 550 light-years away, is one of the brightest in the night sky. Its distinctive red glow will vanish behind the illuminated lunar disk for up to an hour, depending on the observer's latitude. The event requires clear skies and a dark vantage point.
Visibility favors the Americas, parts of West Africa, and Europe. In the continental United States, the occultation will be visible from the West Coast and central states, with the moon about 20 degrees above the horizon. East Coast observers will see the moon set just before the event begins.
This is not a once-in-a-lifetime show but a moderately rare alignment—similar occultations of Antares occur roughly once every few years. The Blue Moon label, while evocative, refers simply to the second full moon in a calendar month and does not affect the star's appearance.
A counter argument: Some astronomers argue that the term "Blue Moon" has been overused in popular media, and that the event's significance is inflated for public engagement. The occultation itself, while visually striking, offers limited scientific value compared to other lunar occultations used to refine stellar diameters or detect close companions.