When is the next solar eclipse?
The next total solar eclipse is April 8, 2024, and the next annular solar eclipse is October 2, 2024. If you happen to be in a location where you can observe one or both of the upcoming eclipses, there are important safety considerations to keep in mind.
Read on to learn more about solar eclipses and how to keep your eyes protected while viewing this natural phenomenon.
What causes a solar eclipse?
A solar eclipse is a rare event that occurs when the moon passes between the Earth and the sun. There are three types of solar eclipse:
- Total solar eclipse – The moon completely covers the face of the sun. The sky darkens and the corona (the sun's outermost atmosphere) becomes visible during a total eclipse.
- Partial solar eclipse – The moon passes in front of the sun but does not cover it completely. A bright crescent-shaped portion of the sun becomes visible during a partial eclipse.
- Annular solar eclipse – The moon passes in front of the sun, but it is too far away to cover the sun completely. A bright ring of light or "ring of fire" becomes visible around the silhouette of the moon.
Where to view the 2024 solar eclipses
Solar eclipses can be seen from various locations worldwide.
The total solar eclipse on April 8, 2024, will be visible in parts of Canada, Mexico and the U.S., including:
- Arkansas
- Illinois
- Indiana
- Kentucky
- Maine
- Missouri
- New Hampshire
- New York
- Ohio
- Oklahoma
- Pennsylvania
- Texas
- Vermont
The upcoming October 2, 2024, annular solar eclipse will be visible across parts of the Pacific Ocean and South America, crossing land only over:
- Chile
- Argentina
- Rapa Nui (Easter Island)
What happens if you look at a solar eclipse?
Staring at the sun without proper eye protection can result in a condition called solar retinopathy or solar maculopathy. When exposed to intense sunlight like during a solar eclipse, the cells in the retina can become damaged and cause long-term vision issues.
Symptoms of solar retinopathy may not be immediate, but they can include:
- Blurry vision
- Reduced visual acuity
- Photophobia – Light sensitivity
- Scotoma – A blind spot in one or both eyes
- Dyschromatopsia – When you experience changes in how you see colors
- Metamorphopsia – When shapes or objects appear distorted
- Micropsia – When objects appear smaller than they actually are
- Headaches
Symptoms of solar retinopathy, or "eclipse blindness" can happen within a few hours or days. Solar retinopathy causes visual symptoms, not eye pain. The most common symptom is an apparent blind spot. If you experience vision symptoms after viewing a solar eclipse, seek immediate medical attention.
Can you go blind from looking at a solar eclipse?
Vision loss can occur if you look directly at a solar eclipse without proper protection, though you’re more likely to experience a permanent blind spot or sense of visual distortion. Most people’s vision usually improves on its own after a few months, but vision changes that have not improved after about six months are likely to be permanent.
While there is no specific treatment for solar retinopathy, it is still important to see an eye doctor if you notice new changes in your vision after viewing a solar eclipse. In all, depending on the amount of damage incurred, it is possible to recover from solar retinopathy, but it can take weeks or months of healing.
How to view an eclipse safely
There is only one way to view an eclipse directly without damaging your eyes:
Solar eclipse glasses
The only way to properly protect your eyes while looking directly at a solar eclipse is with certified solar eclipse glasses. Traditional sunglasses do not provide enough protection from an eclipse, no matter how dark the lenses are.
To be considered safe for use during an eclipse, solar viewers and eclipse glasses must have a mark indicating that they meet the requirements for international safety standard ISO 12312-2. Learn more about ISO certification from the American Astronomical Society.
To get your pair of certified eclipse glasses, check with your public library or a nearby home improvement store. Make sure any viewer you get is intact before using it — in other words, no rips, scratches, punctures or tears. It’s also important to check the expiration date because eclipse glasses use materials that can degrade over time.
Leftover eclipse glasses can be recycled or donated to Astronomers Without Borders.
How to observe an eclipse indirectly
If you can’t find any ISO-certified eclipse glasses, it’s still possible to observe the effects of a solar eclipse indirectly. Even though you aren’t looking directly at the sun, you can still get a sense of what’s happening without putting your eyes at risk.
Pinhole projector
One of the most popular methods of indirect eclipse observation is to use a pinhole projector. The best part of this option is that you can make a pinhole projection system at home.
The Exploratorium in San Francisco recommends using the following materials:
- A cardboard box or tube at least six feet long
- Aluminum foil
- Duct tape
- A pin
- A plain sheet of white paper
Once you have everything you need, visit the Exploratorium website for instructions on how to make your own pinhole projector.
Your hands
Using your hands is a more simple way to view a solar eclipse indirectly. With your back to the sun, cross the fingers of one hand over the fingers of your other hand to create a grid pattern. Then watch the shadow made by your outstretched hands on the ground in front of you. The spaces between your fingers will project images of the eclipse onto the ground.
Tree leaves
For a more creative approach to indirect observation, try using the shadows made by tree leaves to view an eclipse. During a partial solar eclipse, the spaces between the leaves project images of the eclipse onto the ground. Many people use this method if they don't have access to eclipse glasses or a pinhole projector.
What to do (and not do) during a solar eclipse
The American Astronomical Society offers a helpful list of do’s and don'ts for viewing a solar eclipse safely:
- DO inspect all eclipse glasses and solar viewers before use. If the lenses are damaged, they are not safe to use.
- DO keep your prescription glasses on when using eclipse glasses or a solar viewer. Eclipse glasses can be worn over your glasses during the eclipse to protect your eyes and allow you to see clearly.
- DO supervise young children to make sure they do not look at the eclipse without proper eye protection.
- DO NOT look at the eclipse through a phone, camera, telescope, or binoculars, even when wearing eclipse glasses. Different solar filters have to be used for these magnified lenses and must be applied to the front of the lens according to their special instructions.
- DO NOT remove your eclipse glasses until the eclipse has completely finished and you are no longer looking at the sun.
- DO NOT use homemade eclipse glasses or ordinary sunglasses to view a solar eclipse. They are not ISO-certified and will not protect your eyes from possible damage.
Be sure to take the proper safety precautions while viewing the April 8 and October 2, 2024 solar eclipses. Take part in one or both of these ultra-rare experiences without putting your eyes at risk.
