If you live in the middle Atlantic or southeast part of the United States, you’ll have an opportunity on Saturday evening, April 25, to see a 70% illuminated waxing gibbous moon gradually drift toward and ultimately hide the 1st-magnitude star, Regulus, the brightest star of the constellation Leo the Lion.

This event is called an occultation, a word that is derived from the Latin occultāre, which means literally “to conceal.” And if you are fortunate enough to live in the zone of visibility for this event (see below), that’s exactly what you will see on Saturday evening: the moon, appearing to temporarily conceal Regulus from your view.

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The star will reappear from behind the moon’s sunlit edge sometime later. To see the reappearance, you’ll most definitely need a telescope, since the star will be buried in the glare of the moon’s brilliant limb — a tiny blue-white diamond suddenly and dramatically erupting into view on the lunar horizon.

Observers along New Jersey’s narrow graze line will see Regulus blink on and off as the moon’s rugged limb passes in front of it. (Image credit: Joe Rao (background added in Canva Pro))

the sun is low to the horizon. Of course, it also helps when you know in advance that the star is situated right next to the moon.

For all the above-mentioned locations, the reappearance of Regulus will occur either in a completely dark sky or during deep (late) twilight.


Regulus’ path behind the moon from six cities. Near the northern limit, the star grazes the moon’s upper edge. (Image credit: Graphic by Joe Rao, who plotted the various paths onto a view of the moon from NASA’s Scientific Visualization Studio. Background added in Canva Pro.)

International Occultation Timing Association (IOTA). Times are given in Universal Time (UT) and included is a color-coded map depicting the region of visibility.

Joe Rao serves as an instructor and guest lecturer at New York’s Hayden Planetarium. He writes about astronomy for Natural History magazine, Sky and Telescope, The Old Farmer’s Almanac and other publications.