Lucky sky-watchers in the western U.S. are in for a treat Sunday: an annular eclipse.

That’s when the Earth and moon's relative orbital positions leave the moon too small to completely cover the sun, from our point of view. The result is a black disk encircled by a brilliant ring of fire. It’s the first time since 1994 that an annular eclipse will hit the mainland U.S.

Up to 94 percent of the sun will be blocked out—but you’ll still need a pinhole viewer or solar filter to view it safely. Weather permiting, the eclipse will be visible in several western U.S. states on the evening of May 20th. The eclipse path crosses Medford, Oregon; Chico, California; Reno, Nevada; much of the Grand Canyon; and Albuquerque, New Mexico. It will also cross Tokyo on the morning of May 21st, Japanese time. A partial eclipse can be seen from many more locations. For a map of where the eclipse will be visible, and when, go to bit.ly/solarpath.

If can’t see this eclipse, perhaps you’ll have better luck in 2017. That’s when a total eclipse of the sun will sweep across the U.S., giving you a chance to stand in the shadow of the moon.

—John Matson

[The above text is a transcript of this podcast.]