The total solar eclipse has 10 distinct phases — here’s what they look like

source
Rick Fienberg / TravelQuest International / Wilderness Travel

Parts of the US will get to see a total solar eclipse on August 21.

While the entire country will get to witness at least a partial eclipse, the lucky people who live along a 70-mile-wide streak will be able to see totality – when the moon crosses between the Earth and the sun, completely blocking out the sun’s light.

For those who plan to watch the total solar eclipse in person or via livestream, there are a few key stages to keep an eye out for as the moon makes its way across the sun.


The eclipse kicks off with what’s called first contact, when the moon starts to pass across the sun.

source
Getty Images

The moon will continue to cover up the sun, forming what’s known as a “crescent sun,” that looks like this.

caption
An airplane flies in front of the crescent of a solar eclipse.
source
Shutterstock

After about an hour or so, the moon will almost completely block out the sun. At that point, you’ll start to see a bright light radiate out of the sliver of distance between the sun and the moon, known as the “diamond ring.”

source
Romeo Durscher/NASA Goddard Space Flight Center/Flickr

A few seconds before totality begins, you can start to see an effect called “Baily’s beads”, in which the sunlight passes through the valleys on the surface of the moon. It lasts for only a few moments before the totality begins.

caption
Baily’s beads, seen in 2002
source
Credit: Arne Danielson

Totality begins when the moon makes its second contact with the sun and entirely blocks it out. The view is about as bright as a full moon, and it’s safe to look without your solar filter glasses. (But that’s only true during totality.)

source
Beawiharta Beawiharta/Reuters

During the total eclipse, you can see the corona — the sun’s outer atmosphere — surrounding the moon. Mark Littman and Fred Espenek, authors of “Totality: The Great American Eclipses of 2017 and 2024” recommend looking to see whether the corona looks symmetrical, or if it bunches up around the poles of the sun.

caption
The sun’s outer atmosphere, or corona, during a total solar eclipse.
source
M. Druckmüller/NASA

Source: “Totality: The Great American Eclipses of 2017 and 2024


During this eclipse, totality will last a maximum of 2 minutes and 43 seconds. After that, the moon will continue on its way, making its third contact of the eclipse. Once again, you’ll briefly see Baily’s beads though (your solar filters should go on again).

caption
Baily’s beads, seen in 2002
source
Robert Slobins

According to NASA, the longest possible total solar eclipse will occur on July 16, 2186. That will last 7 minutes and 30 seconds, and pass through Colombia, Venezuela and Guyana.


The light will start to intensify, creating another “diamond ring.”

caption
The “diamond ring” phase of a total solar eclipse.
source
Dave Mosher

You’ll then start to see the crescent sun of a partial eclipse once again.

source
Rick Fienberg / TravelQuest International / Wilderness Travel

Soon after, the experience will be complete. At the fourth contact, the moon will cease to cover up the sun.

source
Rick Fienberg / TravelQuest International / Wilderness Travel

As a reminder, the only time you can take your glasses off while looking at the eclipse is the few minutes of totality. If you’re still trying to find a pair of glasses, here’s where you might still be able to snag some for free. Those trying to take photos of the eclipse’s stages should be careful with their cameras, too.