How to See the Diamond Ring Effect During a Total Solar Eclipse

The diamond ring effect is one of the most distinctive features of a total eclipse of the Sun. It appears immediately before and after totality, the period when the Sun is completely obscured by the Moon.

The “diamond ring” first appears 10 or more seconds before totality: a dazzling burst of light that clings to one edge of the Moon as the soft glow of the corona emerges from the background sky and silhouettes the opposite edge. Its striking resemblance to a diamond engagement ring is unmistakable. After totality, the effect is briefly visible once again.

To see the diamond ring, experts recommend wearing your solar eclipse glasses until totality has begun — that is, when the crescent Sun is no longer visible through the glasses. It’s then safe to remove the glasses so you can marvel at views of the incomparable solar corona. Of course, by that time, the opportunity to see the diamond ring before totality is already over.

But fear not. A better opportunity for those watching with the unaided eye is to catch the diamond ring just after totality ends. At that time, a dazzling starburst will appear and quickly grow along one edge of the Moon as the diamond ring forms. Take a second to admire it, then cover your eyes with your solar eclipse glasses. Much longer than that, and the Sun's glare becomes uncomfortably bright, with an increasing risk of danger to your eyes. 

If you’re using this approach, do not use binoculars or a spotting scope — it is not safe.

However, if you are a photographer using a telephoto lens or telescope, and you’re not looking through the optical viewfinder with your eyes, you can remove the solar filter from your camera lens 20 or 30 seconds before totality begins. You can then safely view and photograph the diamond ring by watching your camera’s display screen (or electronic viewfinder). You can do the same thing after totality ends. Just remember to put your solar filter back on your camera lens no more than 20 to 30 seconds after the end of totality. Photos taken during this time are quite spectacular!

This phenomenon is incredibly fast-changing, as the remaining crescent Sun rapidly shrinks and vanishes behind the Moon’s disk. The brilliant jewel of sunlight decreases in intensity while the sky simultaneously darkens, and the corona becomes increasingly prominent.

During the last few seconds, the crescent Sun breaks up to form Baily's beads (those are typically only visible through a telescope with a solar filter attached). At the end of totality, this sequence happens in the reverse order, starting with Baily's beads until the returning burst of sunlight becomes too bright to view with the naked eye. That’s why the end of totality offers the best opportunity to see the diamond ring: You start from “safe mode” instead of having to guess when safe mode starts.

The Diamond Ring through History

The first mention of the diamond ring metaphor appears in the French newspaper Le Figaro, which published the following after the total eclipse of April 18, 1912, in Paris: “A young woman observed the lingering sliver of Sun. As overheard by an on-site Le Figaro reporter, she suddenly exclaimed, ‘On dirait une bague de fiançailles’ (It looks like an engagement ring).” She made the observation without optical aid or magnification.

More references appear after the Moon’s shadow passed through New York City on Jan. 24, 1925. The next day, The New York Times published a story titled, “Scientists Missed Sun’s ‘Diamond Ring,’” which included the following: “This was spontaneously called ‘the diamond ring’ by numbers of observers in New York, and this term, hitherto unknown to astronomy, was apparently fixed forever as a technical term in the literature of the subject by (the following) night.”

That article also contains the first explanation of the diamond ring effect by Princeton professor Henry Norris Russell, who goes on to say it is “an optical illusion experienced by observers with the naked eye.”

Which Comes First? Diamond Ring vs. Baily’s Beads

Given that we’ve been talking about the diamond ring for more than a century, it might surprise you that not everyone agrees on how to define the phenomenon. Some references of the diamond ring effect describe it as “a single Baily’s Bead, shining like a brilliant diamond set into a pale ring created by the pearly white corona ... (signaling) that totality is about to start or has ended.”

Personally, I disagree with this definition. For an observer near the center of the path of totality, Baily’s beads only lasts 3 to 5 seconds. So, by the above definition, the "diamond ring effect" must be shorter, since it is formed by the last bead before totality and the first bead after totality.

Yet from my own experience of observing more that 20 total solar eclipses, I have frequently photographed a diamond ring effect beginning 10 seconds or more before totality, and the effect continues up until the Moon’s disk fully covered the Sun’s. The diamond reappears when totality ends and lasts 10 seconds or more until the sky grows to bright to detect the corona.

In this case, the diamond is actually a blend of several Baily’s beads or a short, continuous arc of photosphere. In other words, magnification (via a telescope) is needed to see the beads, while naked eye viewers will report seeing the diamond ring instead.

Note, however, that a naked-eye viewer can’t be looking at the Sun with so much photosphere exposed –– it’s just too uncomfortably bright (and unsafe). Only a camera can capture that bit of photosphere and the innermost corona at the same time. It’s those views that show a diamond-like effect some 10 seconds before totality.

However you define it, the effect is dazzling. Hopefully on April 8th, you’ll have the chance to see it for yourself.

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Retired NASA astronomer Fred Espenak has traveled to 30 total eclipses of the Sun. His most recent book (along with coauthor Mark Littmann) is Totality - The Great North American Eclipse of 2024. 

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