On February 26, lucky sky-watchers across South America and Africa will witness the sun turn into a dramatic ring of fire due to an event known as an annular eclipse.

A solar eclipse occurs when Earth, the moon, and the sun line up perfectly so that the moon casts a shadow on our planet. However, the moon follows an elliptical orbit around Earth, and over time the distance between the two objects can vary. For sky-watchers, that means the apparent size of the lunar disk in the sky changes, too.

A total solar eclipse happens when the moon is close enough to Earth that it seems to completely cover up the sun. Annular eclipses occur when the moon is farther from Earth