Please feel free to download maps, posters, fact sheet, safety bulletin and other materials for use in your communities and events. We appreciate it if you credit NASA.
How to View the 2017 Solar Eclipse Safely
Looking directly at the sun is unsafe except during the brief total phase of a solar eclipse (“totality”), when the moon entirely blocks the sun’s bright face, which will happen only within the narrow path of totality.
The only safe way to look directly at the uneclipsed or partially eclipsed sun is through special-purpose solar filters, such as “eclipse glasses” (example shown at left) or hand-held solar viewers.
Homemade filters or ordinary sunglasses, even very dark ones, are not safe for looking at the sun; they transmit thousands of times too much sunlight.
Refer to the American Astronomical Society (AAS) Reputable Vendors of Solar Filters & Viewers page for a list of manufacturers and authorized dealers of eclipse glasses and handheld solar viewers verified to be compliant with the ISO 12312-2 international safety standard for such products.
- Always inspect your solar filter before use; if scratched or damaged, discard it. Read and follow any instructions printed on or packaged with the filter.
- Always supervise children using solar filters.
- Stand still and cover your eyes with your eclipse glasses or solar viewer before looking up at the bright sun. After looking at the sun, turn away and remove your filter — do not remove it while looking at the sun.
- Do not look at the uneclipsed or partially eclipsed sun through an unfiltered camera, telescope, binoculars, or other optical device.
- Similarly, do not look at the sun through a camera, a telescope, binoculars, or any other optical device while using your eclipse glasses or hand-held solar viewer — the concentrated solar rays will damage the filter and enter your eye(s), causing serious injury.
- Seek expert advice from an astronomer before using a solar filter with a camera, a telescope, binoculars, or any other optical device. Note that solar filters must be attached to the front of any telescope, binoculars, camera lens, or other optics.
- If you are within the path of totality , remove your solar filter only when the moon completely covers the sun’s bright face and it suddenly gets quite dark. Experience totality, then, as soon as the bright sun begins to reappear, replace your solar viewer to look at the remaining partial phases.
- Outside the path of totality, you must always use a safe solar filter to view the sun directly.
- If you normally wear eyeglasses, keep them on. Put your eclipse glasses on over them, or hold your handheld viewer in front of them.
Note: If your eclipse glasses or viewers are compliant with the ISO 12312-2 safety standard, you may look at the uneclipsed or partially eclipsed Sun through them for as long as you wish.
Furthermore, if the filters aren't scratched, punctured, or torn, you may reuse them indefinitely.
Some glasses/viewers are printed with warnings stating that you shouldn't look through them for more than 3 minutes at a time and that you should discard them if they are more than 3 years old.
Such warnings are outdated and do not apply to eclipse viewers compliant with the ISO 12312-2 standard adopted in 2015. To make sure you get (or got) your eclipse glasses/viewers from a supplier of ISO-compliant products, see the American Astronomical Society (AAS) Reputable Vendors of Solar Filters & Viewers page.
An alternative method for safe viewing of the partially eclipsed sun is pinhole projection. For example, cross the outstretched, slightly open fingers of one hand over the outstretched, slightly open fingers of the other, creating a waffle pattern. With your back to the sun, look at your hands’ shadow on the ground.
The little spaces between your fingers will project a grid of small images on the ground, showing the sun as a crescent during the partial phases of the eclipse.
Or just look at the shadow of a leafy tree during the partial eclipse; you'll see the ground dappled with crescent Suns projected by the tiny spaces between the leaves.
A solar eclipse is one of nature’s grandest spectacles. By following these simple rules, you can safely enjoy the view and be rewarded with memories to last a lifetime. More information:
This document does not constitute medical advice. Readers with questions should contact a qualified eye-care professional.
Additional Safety Information
An eclipse is a rare and striking phenomenon you won't want to miss, but you must carefully follow safety procedures. Don't let the requisite warnings scare you away from witnessing this singular spectacle! You can experience the eclipse safely, but it is vital that you protect your eyes at all times with the proper solar filters.
No matter what recommended technique you use, do not stare continuously at the sun. Take breaks and give your eyes a rest! Do not use sunglasses: they don't offer your eyes sufficient protection. The only acceptable glasses are safe viewers designed for looking at the sun and solar eclipses.
One excellent resource on how to determine if your viewers are safe can be found here: https://eclipse.aas.org/eye-safety/iso-certification
Viewing with Protection – Experts suggests that one widely available filter for safe solar viewing is welders glass of sufficiently high number. The only ones that are safe for direct viewing of the Sun with your eyes are those of Shade 12 or higher. These are much darker than the filters used for most kinds of welding.
If you have an old welder's helmet around the house and are thinking of using it to view the Sun, make sure you know the filter's shade number. If it's less than 12 (and it probably is), don't even think about using it to look at the Sun.
Many people find the Sun too bright even in a Shade 12 filter, and some find the Sun too dim in a Shade 14 filter — but Shade 13 filters are uncommon and can be hard to find.
The AAS Reputable Vendors of Solar Filters & Viewers page doesn't list any suppliers of welder's filters, only suppliers of special-purpose filters made for viewing the Sun.To find out more about eyewear and handheld viewers go to https://eclipse.aas.org/eye-safety/eyewear-viewers.
Telescopes with Solar Filters – Eclipses are best viewed directly when magnified, which means a telescope with a solar filter or solar telescopes.
These will give you a magnified view that will clearly show the progress of an eclipse. Never look through a telescope without a solar filter on the large end of the scope.
And never use small solar filters that attach to the eyepiece (as found in some older, cheaper telescopes.) https://eclipse.aas.org/eye-safety/optics-filters
Pinhole and Related Projection Methods – Pinhole projectors and other projection techniques are a safe, indirect viewing technique for observing an image of the sun.
These provide a popular way for viewing solar eclipses. One viewing technique is to project an image of the sun onto a white surface with a projecting telescope. This is explained further here: http://www.astrosociety.org/education/publications/tnl/05/stars2.html
The Exploratorium demonstrates how to view a planet in transit or an eclipse safely by projecting the image with binoculars: http://www.exploratorium.edu/transit/how.html. There are commercially available projection telescopes as well.
Besides eye protection during solar eclipse viewing, one needs to pay attention to their personal needs and surrounding. Below are some additional safety tips for eclipse observers before, during and after the August 21, 2017 solar eclipse.
Graphics-Only Solar Eclipse Safety Flyer
Car Safety Planning to Drive the Eclipse https://www.ready.gov/car
Camping Health and Safety https://www.cdc.gov/family/camping/ http://www.recreation.gov/recFacilityActivitiesHomeAction.do?goto=camping.htm&activities=9
Heat and Children in Cars http://www.safercar.gov/parents/InandAroundtheCar/heatstroke.htm http://www.safercar.gov/parents/InandAroundtheCar/heat-involved.html
Federal Emergency Management Agency – Are you Ready Food and Water Safety Hazards to Outdoors Workers Heat and Hydration Hiking Safety Large Crowds Safety Personal Safety – At Home, On the Street, While Traveling Personal Safety Save Your Skin
How to Tell If Your Eclipse Glasses or Handheld Solar Viewers Are Safe
We used to say that you should look for evidence that they comply with the ISO 12312-2 international safety standard for filters for direct viewing of the Sun.
But now the marketplace is being flooded by counterfeit eclipse glasses that are labeled as if they're ISO-compliant when in fact they are not.
So now we suggest that you make sure you get (or got) your eclipse viewers from one of the suppliers listed on our Reputable Vendors of Solar Filters & Viewers page.
The #1 rule for observing a solar eclipse, or for looking directly at the Sun at any other time, is safety first.
As noted elsewhere on this site, with one exception, it is never safe to look directly at the Sun without a special-purpose safe solar filter. That exception is during totality, when the Moon completely blocks the dazzlingly bright face of the Sun.
On August 21, 2017, this will happen only within the roughly 70-mile-wide path of the Moon's dark inner shadow from Oregon to South Carolina — and only for a minute or two.
Before and after totality, and at all times outside the path of totality, you must use a special-purpose safe solar filter when looking directly at the Sun.
“Special-purpose” means designed exclusively for looking directly at the everyday Sun. Filters for direct viewing of the Sun are typically sold in the form of wearable “eclipse glasses” or “eclipse shades” or as solar viewing cards that you hold in your hand. What makes them special is that they reduce sunlight to safe levels so that you don't injure your eyes. Our daytime star shines about a half million times brighter than the full Moon in visible light and emits potentially harmful ultraviolet (UV) and infrared (IR) radiation too. Looking directly at the Sun through anything that isn't specially made to deal with all that visible light and invisible radiation is a recipe for serious eye injury, perhaps even blindness. Note that special-purpose solar filters are many thousands of times darker than ordinary sunglasses!
What to Look For
How do you know if your eclipse glasses or handheld solar viewers are truly safe? You need to know that they meet the ISO 12312-2 (sometimes written as ISO 12312-2:2015) international safety standard. Filters that are ISO 12312-2 compliant not only reduce visible sunlight to safe and comfortable levels but also block solar UV and IR radiation.
Unfortunately, you can't check whether a filter meets the ISO standard yourself — doing so requires a specialized and expensive piece of laboratory equipment called a spectrophotometer that shines intense UV, visible, and IR light through the filter and measures how much gets through at each wavelength.
Solar filter manufacturers send their products to specialized labs that are accredited to perform the tests necessary to verify compliance with the ISO 12312-2 safety specifications.
Once they have the paperwork that documents their products as ISO-compliant, they can legitimately use the ISO logo on their products and packaging.
Even more unfortunately, unscrupulous vendors can grab the ISO logo off the internet and put it on their products and packaging even if their eclipse glasses or viewers haven't been properly tested.
This means that just seeing the ISO logo or a label claiming ISO 12312-2 certification isn't good enough.
You need to know that the product comes from a reputable manufacturer or one of their authorized dealers.
The AAS Solar Eclipse Task Force has been working diligently to compile a list of such vendors, now posted on our Reputable Vendors of Solar Filters & Viewers page.
We've checked manufacturers' ISO paperwork to make sure it's complete and that it comes from a recognized, accredited testing facility, and we've personally examined manufacturers' products.
We've asked manufacturers to identify their authorized resellers, and we've asked dealers to identify the source of the products they're selling. Only when everything checks out do we add a vendor to our listing.
If we don't list a supplier, that doesn't mean their products are unsafe — only that we have no knowledge of them or that we haven't convinced ourselves they are safe.
How to know your eclipse glasses are safe
It is safe to view an eclipse through eclipse glasses if the glasses come from a reputable vendor. EarthSky glasses comes from Rainbow Symphony, which is on the AAS-approved list of reputable venders.
The American Astronomical Society (AAS) issued the following statement on August 1, 2017, prior to the August 21 total solar eclipse.
How can you tell if your eclipse glasses or handheld solar viewers are safe? It is no longer sufficient to look for the logo of the International Organization for Standardization (ISO) and a label indicating that the product meets the ISO 12312-2 international safety standard for filters for direct viewing of the sun’s bright face. Why not? Because it now appears that some companies are printing the ISO logo and certification label on fake eclipse glasses and handheld solar viewers made with materials that do not block enough of the sun’s ultraviolet, visible, and infrared radiation to make them truly safe.
Some sellers are even displaying fake test results on their websites to support their bogus claim of compliance with the ISO safety standard.
Given this unfortunate situation, the only way you can be sure your solar viewer is safe is to verify that it comes from a reputable manufacturer or one of their authorized dealers. The AAS Solar Eclipse Task Force has been working diligently to compile a list of such vendors, now posted on its Reputable Vendors of Solar Filters & Viewers page.
Task-force members have checked manufacturers’ ISO paperwork to make sure it is complete and that it comes from an accredited testing facility, and they’ve asked manufacturers to identify their authorized resellers and dealers to identify the source of the products they’re selling. Only when everything checks out does the AAS add a vendor to its listing. AAS Press Officer and task-force representative Rick Fienberg said:
If we don’t list a supplier, that doesn’t mean their products are unsafe. It just means that we have no knowledge of them or that we haven’t convinced ourselves they’re safe.
- Click here for the AAS list of reputable vendors of solar filters and viewers.
- Read more from the AAS about purchasing safe solar filters.
- Enter your zip code to learn how much eclipse you’ll see, and what time
- Read more from the AAS on how to safely view a solar eclipse
Bottom line: Be sure your eclipse glasses come from a reputable supplier, such as a planetarium, science museum or other longstanding science organization. Did you purchase eclipse glasses from EarthSky? We are on the AAS-approved list.
How to tell if your solar eclipse glasses are safe or fake
How to spot fake eclipse glasses
The eclipse economy is in full swing. Eclipse glasses are in low supply, and counterfeit eclipse glasses being sold. How can you tell if the solar eclipse glasses you bought are safe for staring directly at the sun or fakes?
Check the ISO number
According to the American Astronomical Society (AAS), a real and safe pair of solar eclipse glasses should be labeled with ISO 12312-2 (sometimes written in more detail as ISO 12312-2:2015), which is an international safety standard that denotes the glasses reduce visible sunlight to safe levels and block UV and IR radiation.
Reputable vendor research
Unfortunately, fake glasses may also be labeled as being compliant with ISO 12312-2 because, as a general rule, people are greedy, selfish and not to be trusted.
To double check the veracity of your eclipse glasses' ISO claims, you can check to see if the vendor from which you purchased the shades is trustworthy in the eyes of the AAS.
See its list of Reputable Vendors of Solar Filters and Viewers.
In assembling its list, the AAS checks to make sure a manufacturer earned its ISO rating with proper, labs-based testing. It also asks manufacturers for their authorized resellers and resellers for their manufacturers.
If the vendor of your eclipse shades is listed, then you are safe. But the opposite isn't necessarily true. If your vendor isn't listed, it doesn't necessarily mean they are slinging counterfeits.
It just means the AAS hasn't checked them out or hasn't been able to track everything down.
So, what are you to do if your vendor isn't on the list? Perform an eye test.
Eclipse glasses eye test
First off, a pair of honest-to-goodness solar eclipse glasses should be way darker than, say, your sunglasses. According to the AAS, the solar filters of eclipse glasses are “many thousands of times darker” than ordinary sunglasses.
So, your mystery pair of eclipse glasses look pretty darn dark? That's a good start. You should not be able to see anything through them except the sun itself or something similarly bright.
What's something as bright as the sun you can use as a test? The AAS suggests you check sunlight reflected off a mirror or a shiny metal object.
If sun is behind the clouds or on the other side of the earth when you want to test your glasses, you can use a bright-white LED such as the flashlight on your phone or a bare lightbulb. The reflected sunlight or bright, white, artificial light should appear very dim through a safe pair of eclipse glasses.
If you can see light behind a lamp shade or a soft, frosted light bulb through the glasses through your eclipse glasses, then they aren't strong enough to stare safely at the sun.
Will Your Solar Eclipse Glasses Still Be Safe to Use in 2024?
The 2017 total solar eclipse has come and gone, but another one is less than a decade away for North America. And if you purchased paper eclipse glasses, you may be wondering if you can reuse them again for the next total solar eclipse in seven years.
On April 8, 2024, skywatchers will be able to see the moon completely block the sun's light along a path of totality that cuts northward from Mazatlán, Mexico, to Newfoundland, Canada.
So if you purchased solar eclipse glasses for the Aug. 21 event, will they still be good to use in 2024? [Photos: 2017 Great American Solar Eclipse]
“If the filters aren't scratched, punctured or torn, you may reuse them indefinitely,” according to a NASA guideline for eclipse-viewing safety.
However, new paper glasses produced in accordance with globally recognized optical safety regulations — in effect since 2015 and known as International Organization for Standardization (ISO) 12312-2 — are typically printed with a warning that they should be discarded after three years.
Looking directly at the sun without proper optical protection can cause permanent eye damage, and paper eclipse glasses must display ISO 12312-2 certification to be considered safe for use during an eclipse, the American Astronomical Society (AAS) reported.
Punctures, scrapes and scratches that might allow light to leak through the lenses render eclipse glasses unsafe, according to the AAS.
Over time, normal wear as well as environmental factors can make the lenses in paper eclipse glasses more prone to tearing or coming loose, meaning they may not adequately protect your eyes, John Jerit, president of American Paper Optics (APO) — one of the leading manufacturers of ISO 12312-2-compliant eclipse glasses — told Live Science.
And it's impossible to say for sure how well an individual pair of paper glasses is going to hold up over seven years, he added.
“You can't control how people are going to store them,” he explained. “If someone calls me in six years and says, 'Are my glasses still good?' I'm not going to say, 'Send me a picture of your glasses.' I'd say, 'Buy new glasses,' under all conditions, every single time,” Jerit said.
Compliance with ISO certification requires manufacturers to include an obsolescence date alongside the official ISO logo, Jerit told Live Science. For this reason, APO — which has produced eclipse glasses for 25 years — includes a printed recommendation on its glasses to use them for no more than three years.
Eclipse glasses by American Paper Optics are printed with a recommendation to discard the glasses after three years. (Image credit: Live Science)
A second look
But even though you should probably replace your current glasses for eclipse viewing in 2024, that doesn't mean you should just throw out the ones you have.
The organization Astronomers Without Borders is accepting donations of undamaged eclipse glasses to distribute to schools in Asia and South America for a solar eclipse that will cross those continents two years from now, in 2019.
You can also just keep using your glasses to observe the sun, because even when there's no eclipse to see, the unobstructed sun is fascinating to look at, said Emily Rice, an associate professor of astronomy at the City University of New York, College of Staten Island. [Sun Storms: Incredible Photos of Solar Flares]
“The easiest thing to see is going to be sunspots,” Rice told Live Science.
These are dark patches on the sun's surface triggered by powerful magnetic activity, and they wax and wane in frequency over an 11-year cycle. The sun is now at a point in its cycle where sunspot appearances are decreasing — a trend that will continue until 2020 — but those spots that are visible can be bigger than the Earth, Rice explained.
“That's a really nice way to put the size of the sun to scale when you're actually looking at it with your own eyes,” she said.
This image of the sun, captured today (Aug. 25), shows sunspots AR2671 and AR2672. (Image credit: SDO/HMI)
To find a sunspot, you can visit the website Spaceweather.com to view a daily high-resolution image of the sun and pinpoint sunspots on the star's surface. Then, you can look directly at the sun through eclipse glasses to locate the spots and track their movements over time, Rice said.
“Watching the sun from day to day, those sunspots are going to move slightly but perceptibly. You can learn to recognize sunspots, watch them move across sun — you can see sun's rotation with your own eyes pretty easily,” she said.
During sunrise and sunset, the shape and color of the sun are more distorted by Earth's atmosphere. Looking at the sun through eclipse glasses could offer a more detailed view of how the sun is flattened by its proximity to the horizon, and how its colors are affected by scattered light, Rice told Live Science.
Using eclipse glasses to look at the sun when it's high overhead will provide the clearest view, with less atmospheric distortion. At the same time, the sunlight when the sun is at midday strength will also be more intense, so observers should exercise caution even when using protective eyewear, Rice said.
“Be careful not to look for too long. You never want to stare at it, even with eclipse glasses, for more than just a few seconds at a time. High overhead is usually going to be better viewing, but it'll also be more dangerous viewing — it's still the sun,” she added.
The sense of wonder that accompanies the unusual sight of a total solar eclipse is a unique experience. But a little of that wonder can be recaptured by directly observing the daily activity of our closest star as Earth travels around it, Rice said.
“I love looking at the sun and thinking — that's a star that's 93 million miles [150 million kilometers] away. I'm on a rock that's orbiting it. Especially at sunset, when my position on that rock is turning away from the sun, you can almost feel the motion and feel your place in the universe,” Rice said.
“I think that's a really cool thing about being able to look at the sun safely every day —you can feel something much bigger than what might be immediately around you,” she added.
Original article on Live Science.
Eclipse Glasses | Eclipse Sunglasses| Rainbow Symphony
Rainbow Symphony was founded by a passionate eclipse chaser, so inevitably, our eclipse glasses are some of our favorite items. We’ve poured our excitement for scientific discovery and our love for solar viewing into these glasses to ensure the safest means to view any solar event. Explore our selection of eclipse sunglasses, solar viewers, and other accessories.
Safe and Effective Eclipse Glasses
A solar eclipse is a jaw-dropping sight for people of all ages, but it can be dangerous without the aid of proper viewing equipment.
To protect your eyes from harmful solar radiation during exciting solar events, choose the eclipse glasses trusted by the AAS and NASA, and that meet the standard for ISO 12312-2:2015.
These glasses are “CE” Certified and meet the transmission requirements of scale 12-16 of EN 169/1992 for absolutely safe direct solar viewing.
All of our eclipse sunglasses meet the 2012 Transmission Requirements of EN 1836:2005 and AS/NZS 1338.1:1992 for eclipse filters (Queensland Directive).
The lenses on these specialty solar viewers are made of exclusive scratch-resistant material with grade five optical density to guarantee ultimate protection from harmful solar radiation.
The “Black Polymer” filters out 100% of ultraviolet light and infrared light, as well as 99.999% of intense visible light.
The premium filters on the lenses create an orange-colored image of the sun that is sharper and easier to see.
Eclipse Shades For Every Style and Budget
Our line of eclipse glasses and solar eclipse viewer cards provide options for all different classrooms and budget sizes.
For a smaller group –– or one that is amenable to sharing, we offer Plastic Eclipse Glasses in both that fit over optical glasses and wrap-around goggle variations.
For a less expensive alternative, educators will find great value in our paper Eclipse Shades® Safe Solar Glasses.
* * *
Have a question about our solar eclipse filters? Contact us by phone today at 818-708-8400, or by email at [email protected]
Solar eclipse glasses
The solar eclipse of December 26, 2019 seen through a pair of solar eclipse glasses in Jaffna, Sri Lanka.
Solar viewer (also known as solar viewing glasses or solar eclipse glasses) are special eyewear designed for direct viewing of the Sun. Standard sunglasses are unable to filter out eye damaging radiation. Solar viewers are required for safe viewing of solar events such as eclipses. The recommended optical density of this eyewear is 5.
According to the American Astronomical Society (AAS) products meeting the ISO 12312-2 standard avoids risk damage, and issued a list of reputable vendors of eclipse glasses.
The organization warned against products claiming ISO certification, or even citing the exact standard number, but not tested by an accredited laboratory, or those bearing incomplete certification information.
Another problem was counterfeits of reputable vendors' products, some even claiming the company's name (such as with American Paper Optics which published information detailing the differences between its glasses and counterfeits).
Eyewear made prior to 2015, may have a 3 year use limit before they can no longer effectively filter out UV radiation. Starting in 2015, products made with ISO 12312-2 can be used indefinitely as long as they have not been damaged by scratch or tear.
Counterfeit eclipse glasses
In the months leading to the solar eclipse of August 21, 2017, counterfeits of light-filtering glasses for solar eclipses began proliferating, leading to public health issues. Effective eclipse glasses filter visible, ultraviolet, and infrared light. The eye's retina lacks pain receptors, and thus damage could occur without one's awareness.
The AAS said determining whether an eclipse viewer was safe required a spectrophotometer and lab equipment, but often the user should see nothing through the filter except for the Sun, sunlight reflecting off of shiny metal, or intense light sources such as an LED flashlight.
Andrew Lund, the owner of a vendor of eclipse glasses, noted that not all counterfeit glasses were necessarily unsafe. He stated to Quartz that the counterfeits he tested blocked the majority of harmful light, concluding that “the IP is getting ripped off, but the good news is there are no long-term harmful effects.”
On July 27, 2017, Amazon required all eclipse viewing products sold on its website have a submission of origin and safety information, and proof of an accredited ISO certification. In mid-August 2017, Amazon recalled and pulled listings for eclipse viewing glasses that “may not comply with industry standards”, and gave refunds to customers who had purchased them.
- Astronomical solar filter
- Eclipse chasing
- Solar telescope
- Transit of Mercury
- Transit of Venus
- ^ Weisberger, Mindy (2017-08-25). “Will Your Solar Eclipse Glasses Still Be Safe to Use in 2024?”. Live Science. Retrieved 2017-08-28.
- ^ a b Wolfson, Elijah (July 27, 2017). “Solar-eclipse fever means counterfeit glasses are flooding Amazon's market”. Quartz. Retrieved August 19, 2017.
- ^ “How to Tell If Your Eclipse Glasses or Handheld Solar Viewers Are Safe”. Solar Eclipse Across America – August 21, 2017. American Astronomical Society. February 23, 2017. Retrieved August 20, 2017. Includes photos of genuine and fake eclipse glasses.
- ^ Pittman, Travis (August 18, 2017). “Here's How Fast Your Retina Could Burn Looking at Eclipse Unprotected”. Denver, Colorado: 9 News.
- ^ a b “Amazon offers refunds to customers who bought fake eclipse glasses”. CBC News. August 15, 2017. Retrieved August 19, 2017.
- ^ Elliott, Matt (August 19, 2017). “How to tell if your solar eclipse glasses are safe or fake”. CNET. Retrieved August 19, 2017.
Solar Eclipse And Your Eyes
Vision Resources |
By Jeff Herman, chief editor
Whether you choose to view a solar eclipse from your home, a hotel or an open field along roadway, you need to know how to watch a solar eclipse without damaging your eyes.
We've got you covered.
Solar eclipse definition
What causes a solar eclipse?
By definition, a solar eclipse occurs when the moon passes directly (or nearly directly) between the sun and earth, causing the moon to block most of the sun (partial eclipse) or fully block it (total eclipse) for a brief period.
Solar eclipse glasses: The best way to protect your eyes
Solar eclipse glasses are inexpensive, very dark filters with cardboard or paper frames that are designed to protect your eyes from retina damage when viewing an eclipse.
Staring at a solar eclipse (or staring at the sun at any time) can cause a burned retina — called solar retinopathy or solar maculopathy — that can cause permanent vision loss. So having adequate eye protection when viewing a solar eclipse is extremely important.
Certified “eclipse glasses” offer adequate protection from the sun's potentially damaging UV rays when viewing a solar eclipse. Look for documentation somewhere on the disposable glasses that says the eclipse shades are certified to meet the ISO 12312-2 international standard for safe direct viewing of the sun.
Tips to view a solar eclipse safely
Once you have your solar eclipse glasses (and before you look at the sun), the National Science Foundation's American Astronomical Society (AAS) offers this list of solar-eclipse viewing safety tips:
- Always inspect your solar filter before use. If it's scratched, punctured, torn or otherwise damaged, discard your eclipse glasses.
- Always supervise children using solar filters.
- If you normally wear eyeglasses, keep them on. Put your solar eclipse glasses on over them, or hold a handheld solar viewer in front of them.
And AAS provides these solar eclipse viewing tips for photographers:
- Don't look directly at the sun (or partially eclipsed sun) through an unfiltered camera, telescope, binoculars or other device.
- Similarly, don't look at the sun through a camera, telescope, binoculars or any other optical device — even while wearing eclipse glasses. The concentrated solar rays passing through the lens(es) of the optical device could damage the filter of the eclipse glasses and enter your eyes, causing serious injury.
- Seek expert advice from an astronomer before using a solar filter with a camera, telescope, binoculars or any other device. Note that solar filters must be attached to the front of any telescope binoculars, camera lens or other optics.
Ways to view a solar eclipse safely
If you're unable to purchase ISO-certified eclipse glasses prior to a solar eclipse, using a technique called “pinhole projection” is another way you can view it safely.
How do you create a pinhole projection system for safe viewing of a solar eclipse? According to the Exploratorium in San Francisco, you'll need a box that's at least 6 feet long, aluminum foil, duct tape, a pin and a sheet of white paper.
The whole process involves a lot of work (cutting a 1-inch hole in the center of the box, taping a piece of foil over the hole and poking a small hole in the foil with a pin, for starters).
Though this solar-eclipse viewing method is less dramatic than watching directly through eclipse glasses, pinhole projection will protect your eyes from damage.
Use your hands to view the sun
To perform this technique, cross the outstretched, slightly open fingers of one hand over the outstretched, slightly open fingers of the other, creating a grid or waffle pattern.
With your back to the sun, look at the shadow your outstretched hands create on the ground in front of you. The spaces between your fingers in the waffle pattern will project a grid of small images on the ground that will show the sun as a crescent during the partial phases of the eclipse.
View the eclipse through a tree's leaves
Another option is to look down at the shadow created by a leafy tree during the partial eclipse. You'll see the ground dappled with crescent suns projected by the spaces between the leaves on the tree, the AAS says.
Michael Zeiler, GreatAmericanEclipse.com
When is the next total solar eclipse?
If you missed the July 2, 2019, solar eclipse in South America, hold onto your solar-eclipse viewing glasses. Parts of Argentina and Chile will again prime viewing areas for the next total solar eclipse in South America, which will take place on December 14, 2020.
If you missed the 2017 Great American Solar Eclipse, you'll have to wait a while to see another one in the United States. The next total solar eclipse that will be visible in North America will occur in April 2024.
Page updated June 2019