Total Solar Eclipse: What to See
Glimpse the full glory of the Sun’s outer atmosphere, or corona, visible only when the Sun’s disc is completely covered by the moon.
As the moon passes in front of the Sun, the eclipse goes through stages that provide an evolving spectacle, two plus hours of steadily changing views.
Remember: NEVER view any stage of the eclipse except totality with your naked eye. Use safe viewing techniques to preserve your eyesight.
Before the eclipse begins, and after it ends, the full disk of the Sun shines in the sky. The visible surface of the Sun is called the photosphere. While you wait for the eclipse to begin, use safe viewing techniques to look for sunspots, slightly cooler areas on the Sun that look dark compared to the blinding photosphere. The Sun has an 11-year cycle of sunspot activity, and it will reach its time of greatest activity between 2023 and 2025, so there is an excellent chance that you’ll be able to see some sunspots during the April 8, 2024, total eclipse.
You can’t see the moon as it approaches the Sun, but it’s there, as will become obvious at First Contact.
A giant sunspot observed on October 23, 2014. (NASA/SDO)
Stages of a Total Solar Eclipse
The eclipse begins at First Contact, the moment the moon first “touches” the edge of the solar disk, approaching it from the right as seen from the Northern Hemisphere. (It doesn’t actually touch the Sun, of course—but it appears to as it begins to pass in front of the solar disk.)
The moon, invisible until now in the daytime sky, becomes visible as a black disk blocking the Sun. For the next hour and a half, it slowly covers a larger and larger chunk of the Sun.
Over the course of the next hour (or so), the moon slowly covers more and more of the Sun.
Second Contact occurs as the moon completely covers the Sun. On the moon’s leading edge, the last slice of light shines through lunar valleys, breaking up into a chain of bright “pearls” called Baily’s beads.
Then, in the final seconds before the moon completely covers the Sun, there is a last bright flash, combined with an emerging view of the corona—the Sun’s upper atmosphere—encircling the moon. This produces a spectacular effect called the diamond ring. After the diamond ring disappears, you have a couple of seconds to notice another layer of the Sun, the crimson-colored chromosphere, before it, too, is eclipsed.
The Sun is now completely hidden, revealing the full glory of the solar corona. This stage of a total solar eclipse, Totality, is the only time we on Earth can see the corona, which streams out into space above the Sun’s surface. Normally, the corona’s delicate light is outshone by the bright photosphere.
You may see bright pink spots at the Sun’s edges. These are gigantic loops of plasma that rise from the Sun’s surface, called prominences. Their beautiful hue is the color of glowing hydrogen gas.
During totality is the only time you can safely look at the Sun with your naked eye. If you can draw your eyes away from the Sun for a few moments, you’ll notice that the sky has become quite dark, as if it’s twilight, and other stars and planets are visible. If you look out toward the horizon, it is also possible to see light from outside of the shadow that you are standing in, like a 360-degree sunset.
Totality ends at Third Contact, as the leading edge of the moon begins to move off the Sun. Once again, on the opposite side of the moon, the last light of the photosphere shines through mountains and valleys creating Baily’s beads. At totality’s end, resume using safe viewing techniques.
If you look at the ground just before second contact and right after third contact you may see shadow bands marching across the landscape. While not fully understood, these bands are most likely caused by fluctuations in the density of air in the upper atmosphere similar to the cause of the twinkling of stars at night.
Sunlight Restored Moments after Third Contact, the Sun reemerges in a burst of light, creating a second diamond ring on the opposite side of the Sun. As the moon reveals more of the Sun, the corona quickly fades from view in the brightness of the newly restored photosphere.
The eclipse is now nearly over. Fourth Contact, when the outer edge of the moon last touches the Sun, marks its end. From First Contact to this moment takes about two and a half hours.
The sun presents various features to notice during all phases of an eclipse. In this video, Exploratorium astronomer, Isabel Hawkins points out these phenomena and explains why they occur.