Annular Solar Eclipse: Why the Moon Leaves a Ring of Sunlight and Why It Is Never Safe to Look

At the middle of an annular eclipse the Moon sits squarely in front of the Sun, and yet a band of sunlight shows all the way around it. NASA describes the scene as a dark disk on top of a larger, bright disk, which looks like a ring around the Moon. The ring is not a faint glow. It is the Sun itself.

This guide explains why the Moon sometimes falls short of covering the Sun, which part of its shadow reaches the ground, how long a ring can last and why NASA says there is no safe moment to look without eye protection. It ends with a task in the Alignment Bench.

What an annular solar eclipse is

NASA says an annular solar eclipse happens when the Moon passes between the Sun and Earth while it is at or near its farthest point from Earth. Because the Moon is farther away, it appears smaller than the Sun and does not completely cover it. NASA's explanation of eclipse geometry calls the leftover ring of sunlight an "annulus." NASA's pages on the 2023 eclipse call the effect a "ring of fire."

NASA's eclipse FAQ calls an annular eclipse a special type of partial eclipse, because the Moon blocks all of the Sun except a small ring around the edge. NASA's eclipse tables list it as its own type, because a different part of the Moon's shadow reaches Earth. The two views come from different NASA pages. They describe the same event and only draw the groups differently.

Why the Moon falls short

NASA's geometry page says the Sun is about 400 times bigger than the Moon and about 400 times farther away, so the two look almost the same size. Almost is the key word. Both orbits are slightly oval, so the Moon's distance changes over a month and Earth's distance from the Sun changes over a year.

NASA's Moon fact sheet gives the Moon's mean perigee, its closest point, as 0.3633 million kilometers, about 226,000 miles. The mean apogee, its farthest point, is 0.4055 million kilometers, about 252,000 miles. The sheet adds that over the year the distance roughly ranges from 357,000 to 407,000 kilometers, or about 222,000 to 253,000 miles.

The Sun changes size too. NASA's Five Millennium Canon of Solar Eclipses gives the Sun's apparent width as 1,952 seconds of arc at perihelion, in early January, and 1,887 at aphelion, in early July. The Canon says the Sun's larger size at perihelion makes annular eclipses more frequent around that time. It counts annular eclipses as more likely from November through January than from May through July.

The antumbra and the path of annularity

NASA's geometry page names the shadow part that matters here. The part of the Moon's shadow that extends from the end of the umbra is called the antumbra. Observers inside the antumbra see the annular eclipse. Observers in the penumbra see only a partial eclipse. The path the antumbra traces across Earth is the path of annularity. For the annular eclipse of October 14, 2023, NASA's path table lists a width of 187.4 kilometers, about 116 miles, at greatest eclipse, with a central duration of 5 minutes 17.2 seconds.

NASA's eclipse glossary adds a helpful detail. From inside the antumbra, the Sun appears larger than the Moon, which is seen in complete silhouette. The antumbra is like the penumbra in one way: the Sun is only partly blocked.

The drawing is the Bench's side view with the Moon at its far position, 0.3 degrees above the plane of Earth's orbit.

NASA's eclipse maps use a number called eclipse magnitude, the fraction of the Sun's diameter covered by the Moon. It is always less than 1.0 for partial and annular eclipses, and 1.0 or more for total and hybrid eclipses.

How long a ring lasts

Annularity is the stretch when the Moon's whole disk is seen against the Sun. NASA's glossary says it can last from a fraction of a second to a maximum of 12 minutes 29 seconds. The same glossary gives a maximum of 7 minutes 32 seconds for totality. A ring can stay up much longer than a total phase.

How common annular eclipses are

NASA's Canon counts 11,898 solar eclipses from 2000 BCE to 3000 CE. Annular eclipses are 3,956 of them, or 33.2 percent. That is a little more than total eclipses, at 26.7 percent. When an eclipse is total in some places and annular in others, NASA calls it hybrid. Hybrids are 4.8 percent.

Watching safely

NASA is direct about annular eclipses. The Sun is never completely blocked by the Moon, so it is never safe to look directly at the Sun without specialized eye protection designed for solar viewing. NASA also says partial and annular eclipses differ from total ones in one way that matters: there is no period of totality, when the Moon completely blocks the Sun's bright face.

NASA's eclipse glossary describes the Sun at maximum as a blindingly bright ring. It also says that even when 99 percent of the Sun's surface is covered during the partial phases of a solar eclipse, the remaining crescent is still intense enough to cause permanent retinal damage. The danger grows if you look through binoculars or other optical aids.

Here are NASA's rules for watching an annular eclipse:

• Look through safe eclipse glasses or a safe handheld solar viewer at all times.
• Do not use regular sunglasses. NASA says they are not safe, no matter how dark.
• Choose viewers that ought to comply with the ISO 12312-2 international standard. NASA does not approve any particular brand.
• Check the glasses before use and discard them if they are torn, scratched or damaged. Supervise children.
• Do not look through a camera lens, telescope or binoculars while wearing eclipse glasses. Those devices need their own solar filter, fixed over the front.
• With no glasses, use an indirect method such as a pinhole projector, with the Sun at your back. Never look at the Sun through the pinhole.
• Wear sunscreen, a hat and protective clothing, because you may be in direct sunlight for hours.

The guide to watching eclipses safely gathers these rules in one place.

Common mistakes

• Taking the glasses off at the ring. There is no moment of totality, so there is no moment when the naked eye is safe.
• Thinking a ring means a weak Sun. NASA's glossary calls it a blindingly bright ring, and a thin crescent of the Sun can still damage the retina.
• Believing the Moon shrinks. NASA says it only appears a little smaller than normal at apogee, because it is farther away.
• Mixing up the umbra and the antumbra. The umbra gives totality. The antumbra, which begins where the umbra ends, gives the ring.
• Thinking annular eclipses are rare. In NASA's count of 11,898 eclipses they are slightly more common than total ones.
• Using eclipse glasses with a camera or telescope. NASA says glasses and handheld viewers are not for use with optics.
• Putting the Moon at its near position in the Bench and expecting a ring. A near Moon points toward a total eclipse.

Try it in the instrument

Open the Alignment Bench and set the sky to an annular solar eclipse. Three settings decide the result.

1. Phase: New Moon. Solar eclipses only occur at a New Moon, according to NASA.
2. Height: close to zero. The Moon's orbit is inclined about 5.1 degrees to Earth's orbit. Fred Espenak of NASA's Goddard Space Flight Center writes that a solar eclipse is visible from somewhere on Earth if the New Moon is within about 17 degrees of a node. NASA's eclipse maps call an eclipse central, meaning total, annular or hybrid, when the shadow axis passes within 0.997 Earth radii of Earth's center. An annular eclipse needs the same near-perfect line-up as a total one.
3. Position: far. The Moon is near its farthest point, so its umbra does not reach Earth, and the antumbra lands there instead.

The line-up is the same as for a total solar eclipse. Only the distance changes the result. The Bench is a simplified model with two New Moon positions and a range of accepted heights around zero, so it teaches the relation and does not forecast real eclipses.

Questions people ask

Why does the Sun look like a ring in an annular eclipse?

The Moon is at or near its farthest point, so it looks smaller than the Sun. It covers the middle and leaves a ring of sunlight around the edge, according to NASA.

Is it ever safe to look at an annular eclipse without protection?

No. NASA says the Sun is never completely blocked, so it is never safe to look directly at the Sun without specialized eye protection designed for solar viewing.

How long can the ring last?

NASA's glossary says annularity can last from a fraction of a second to a maximum of 12 minutes 29 seconds.

Are annular eclipses rarer than total eclipses?

No. In NASA's count of 11,898 solar eclipses between 2000 BCE and 3000 CE, 33.2 percent are annular and 26.7 percent are total. That count covers the whole Earth, not one place.

Sources

• Types of Solar Eclipses, NASA Science. https://science.nasa.gov/eclipses/types/. Opened November 9, 2026.
• Why Do Eclipses Happen?, NASA Science. https://science.nasa.gov/eclipses/geometry/. Opened November 9, 2026.
• Annular Eclipse Safety, NASA Science. https://science.nasa.gov/eclipses/future-eclipses/eclipse-2023/safety/. Opened November 9, 2026.
• Eclipse Viewing Safety, NASA Science. https://science.nasa.gov/eclipses/safety/. Opened November 9, 2026.
• 2023 Annular Eclipse, NASA Science. https://science.nasa.gov/eclipses/future-eclipses/eclipse-2023/. Opened November 9, 2026.
• Eclipses Frequently Asked Questions, NASA Science. https://science.nasa.gov/eclipses/faq/. Opened November 9, 2026.
• Glossary of Solar Eclipse Terms, NASA Goddard Space Flight Center, Eclipse Web Site (Fred Espenak). https://eclipse.gsfc.nasa.gov/SEhelp/SEglossary.html. Opened November 9, 2026.
• Key to Solar Eclipse Maps, NASA Goddard Space Flight Center, Eclipse Web Site (Espenak and Meeus). https://eclipse.gsfc.nasa.gov/SEcat5/SEmapkey.html. Opened November 9, 2026.
• Periodicity of Solar Eclipses, NASA Goddard Space Flight Center, Eclipse Web Site (Fred Espenak). https://eclipse.gsfc.nasa.gov/SEsaros/SEperiodicity.html. Opened November 9, 2026.
• Path of Annular Solar Eclipse of 2023 Oct 14, NASA Goddard Space Flight Center, Eclipse Web Site (Fred Espenak). https://eclipse.gsfc.nasa.gov/SEpath/SEpath2001/SE2023Oct14Apath.html. Opened November 10, 2026.
• Five Millennium Canon of Solar Eclipses: -1999 to +3000 (2000 BCE to 3000 CE), NASA Technical Publication TP-2006-214141 (Espenak and Meeus). https://eclipse.gsfc.nasa.gov/5MCSE/5MCSE-Text11.pdf. Opened November 9, 2026.
• Moon Fact Sheet, NASA Space Science Data Coordinated Archive. https://nssdc.gsfc.nasa.gov/planetary/factsheet/moonfact.html. Opened November 9, 2026.

We opened each source ourselves on the date shown. The drawings are our own and were checked against the numbers in these sources.

Read next

• Total Solar EclipseA total solar eclipse is the Moon's darkest shadow, the umbra, landing on Earth.
• Partial Solar EclipseA partial solar eclipse happens when only the Moon's outer shadow, the penumbra, reaches Earth, so the Sun is covered in part and never fully.