Annular eclipses demonstrate just how perfect the size-distance ratio has to be to produce a total solar eclipse. The Moon’s orbit around Earth is elliptical, meaning it comes closer to Earth at certain points in this orbit and farther at others. The difference between the two extremes is about 40,000 kilometers (about 25,000 miles), which creates a change of about 14% in the Moon’s apparent size from Earth.

When syzygy coincides with apogee (the point in the Moon’s orbit when it’s farthest from Earth), the Moon doesn’t completely cover the Sun. Instead, a ring of sunlight remains visible around the edges, which is why an annular eclipse is often referred to as a “ring of fire” eclipse.

Locations closer to the poles, such as the Arctic and Antarctic regions, see annular eclipses more often than locations closer to the equator because the Moon is slightly farther away from Earth’s poles than from its equatorial regions, making its apparent size in the sky slightly smaller.