On Saturday, the moon will pass in front of the sun, obscuring much of it but leaving behind a brilliant ring, or annulus, of unfiltered sunlight in parts of the western United States. This is known as an “annular” or “ring of fire” solar eclipse.

Only a narrow swath from Oregon to Texas as well as parts of Mexico, Central America, Colombia and Brazil will be able to see the full ring of fire, but the entire Lower 48 states will witness at least a partial solar eclipse.

This annular solar eclipse is different from a total solar eclipse, even though they both happen when the moon intercedes between the Earth and sun. During a total solar eclipse, the moon fully blocks the sun — whereas during an annular solar eclipse, the moon isn’t large enough to entirely cover the solar disk. That leaves behind a hollowed-out sun surrounded by narrow circlet of sunlight.

For areas outside the swath of where this ring of fire will be visible — which is most of the Lower 48 states — a partially eclipsed sickle-shaped or croissant-shaped sun will be visible.

To view either the ring of fire annular eclipse or the partial eclipse, you’ll need protective eclipse glasses to avoid permanent eye damage when watching it.

Sunday marks exactly six days until the annular eclipse and also six months to day until the more dramatic total solar eclipse on April 8, 2024. Day will turn to night as the moon extinguishes sunlight for upward of four minutes, allowing the sun’s atmosphere — the ghostly-white corona — to emerge, along with individual stars, also along a narrow swath.

What is an annular eclipse?

All solar eclipses require the moon to block sunlight from reaching the Earth. The moon’s orbit around Earth is elliptical though, meaning its distance from Earth varies. Subsequently, how large it appears in our sky varies.

The moon and sun appear the same size in our skies. Though the sun is 400 times wider, the moon is 400 times closer.

During apogee, or the farthest point in the moon’s orbit, the moon appears smaller — about 14% smaller, and 30% less bright. Perigee, on the other hand, is when the moon is closer. (That’s when “super moons” occur.)

The moon will be at apogee on Oct. 10, about 251,919 miles away from Earth. (At perigee, on Oct. 26, the moon will be 25,198 miles closer.) Since the eclipse is happening closer to apogee, the moon is farther away and will be more diminutive in our sky, and not able to cover the sun.

That’s why, even with the moon passing directly in front of the sun, the edges of the sun are still visible. If the moon was closer, it would be a total solar eclipse.

Which big cities are in the path of the ring of fire?

For Saturday’s annular eclipse (Oct. 14), areas between Eugene and Medford in Oregon will see the eclipse during the midmorning; 1 hour and 9 minutes of partiality will give way to the ring of fire at about 9:15 a.m. local time.

Then the path will then sweep over Elko, Nev. (9:22 a.m. local time) and southern Utah. After that, it makes a beeline for Albuquerque (10:34 a.m.), which sits smack dab on the centerline and will see 4 minutes 51 seconds of “annularity.” Coincidentally, Balloon Fiesta, a festival of hundreds of hot air balloons that attracts between 800,000 and 1 million guests, will be ongoing at the time. (Author’s note: I’ll be there.)

After that, Roswell, N.M. (10:38 a.m.) is next up, and then Midland (11:43 a.m.), San Antonio (11:52 a.m.) and Corpus Christi (11:55 a.m.) in Texas.

Interactive maps and tools at NASA and timeanddate.com will supply the exact time of the eclipse at specific locations.

How rare are annular eclipses?

The last annular eclipse visible from the United States occurred May 20, 2012; it delivered a stunning sunset ring of fire that was captured far and wide across Texas and the Southwest.

The next one in the United States won’t be until 2046. Even then, only a sliver of southern Oregon, northern California, extreme northwest Nevada and southwest Idaho will see the show.

Total solar eclipses happen over a given location only once on average every 375 years. Annular eclipses, like this one, are just slightly more common.

How can I view it?

Eclipse glasses! During a total eclipse, you can take off your glasses during the peak of the show when the sun is fully covered. But during annular eclipses, the sun is never fully blocked, so you must keep your eclipses glasses on.

There’s nothing “special” about the sunlight that reaches Earth during a solar eclipse. But, simply stated, if you wouldn’t ordinarily stare at the sun, don’t do so during an eclipse.

Alternatively, you can also make a “pinhole projector” to replicate an image of the sun, or look for miniature projections in the shades of trees.

What’s more dramatic: a total solar eclipse or an annular eclipse?

Undoubtedly a total solar eclipse. It’s a heightened sensory experience that simply can’t compare to anything else. The sun becomes replaced by a perfectly-spherical jet-black void in the sky, the air temperature suddenly drops, a minutes-long nightfall interrupts the day and the sun’s atmosphere appears. That’s not to mention the 360-degree twilight that encircles the horizon, representing where the sun is still shining just outside the incredibly narrow zone basking in the moon’s shadow.

(Author’s note — I’ve seen the northern lights, stood in the eyes of major hurricanes, chased down fifteen tornadoes and camped beneath meteor showers. Nothing compares to a total solar eclipse.)

That said, annular eclipses are still cool; being able to witness the rendezvous of two celestial bodies is an ephemeral experience few get to have. You may also notice a strange sepia-like dimming of the daylight even if the sun is never fully extinguished. And besides — the event is just an appetizer for April 8, 2024, when a total solar eclipse marches from the Texas-Mexico border to Maine.

Geoff Chester contributed to this report.