Moon and Antares

The gibbous Moon and the heart of the scorpion — the star Antares — play a game of “hide and seek” this evening. The Moon will pass in front of Antares as seen from most of the United States, hiding the bright star from view.

The event is an occultation. The name comes from the Latin word “occult” which means “to hide.”

Occultations happen because Antares and the Moon follow similar paths across the sky.

Antares is almost atop the ecliptic — the Sun’s path. The Moon stays close to the ecliptic as well. So every month, it passes close to the scorpion’s bright heart. But the Moon’s orbit is tilted a bit, so the Moon doesn’t always cover Antares.

Occultations come in series, when the Moon’s orbital cycles bring it into the proper alignment. In fact, tonight’s occultation is the first in a series that will continue for five years. But the circumstances of each occultation are different, so each one is visible from a different part of Earth. From the United States, we’ll see only a few — with tonight’s as one of the best of the bunch.

The occultation gets under way at 8:20 p.m. Central Daylight Time, and continues for more than two hours. But the exact timing varies depending on location. From Kansas City, for example, Antares will disappear around 9:20 and return to view more than an hour later. Most of the U.S. will see the beginning, the end, or all of this game of celestial hide and seek.

Script by Damond Benningfield