Moon and Regulus

The last-quarter Moon moves toward a familiar companion late tonight: Regulus, the “heart” of Leo, the lion. The bright star rises below the Moon, and is in good view by 1 o’clock. The Moon will slide closer to Regulus during the night.

Regulus sits almost directly on the ecliptic — the Sun’s path across the sky. The Moon stays close to the ecliptic as well. That means the Moon can pass in front of Regulus, blocking the star from view. Such an event is called an occultation, from a Latin word that means “to hide.”

Occultations happen only when the Moon is crossing the ecliptic at the same time it’s passing Regulus. Thanks to that geometry, occultations come in bunches that are about eight or nine years apart. The last bunch wound up in July of 2017. The next one will begin in July 2025 and end a year and a half later.

The Moon isn’t the only body than can occult the star — so can the planets. Because the planets are much smaller targets in our sky, though, such events are quite rare. The last one came in 1959, with Venus crossing in front of Regulus. And our neighbor planet will repeat the performance in 2044.

For now, though, nothing is blocking our view of the lion’s magnificent heart. Watch it trail the Moon across the sky beginning after midnight. And if you miss it tonight, they’ll pair up again tomorrow night — but with the Moon following the star.

Tomorrow: the lion breathes fire.

Script by Damond Benningfield