Morehead educator Amy Sayle is holding a pair of glasses that could save your vision … or destroy your eyes.
The glasses are eclipse glasses — a simple cardboard frame around a black polymer film. The film is designed especially to protect your eyes if you look at the Sun during an eclipse or a transit.
How are eclipse glasses different from regular sunglasses? They are much, much, much more effective at blocking visible light. Researchers measure this using VLT (Visible LIght Transmittance), a standard for comparing different types of glasses. Clear glass transmits more than 90 percent of visible light. Regular sunglasses can transmit anywhere from 15 percent to 30 percent of visible light. Mount Everest explorers, skiers and others who are outdoors in high altitudes might use extra-dark “glacier glasses,” which transmit from 4 percent to 10 percent of visible light.
Eclipse glasses surpass all other glasses in eye protection; they transmit less than 1 percent of visible light. They also block 100 percent of all UVA and UVB light, which is not visible. They are the only glasses that provide adequate eye protection for viewing the Sun during eclipses and transits.
To save your vision, you must use eclipse glasses correctly:
- They must be in mint condition, with no holes or creases.
- They must shield your eyes completely when you look at the Sun.
- They must be used only for naked-eye viewing.
If you don’t use eclipse glasses correctly, however, you can destroy your eyes — literally!
Look closely at the photo. See the holes in the glasses? This is what happens if someone uses the eclipse glasses together with binoculars or a telescope to view the Sun. The magnification of the binoculars or telescope intensify the Sun’s light so strongly that it melts the film. Imagine what it would do to your eye. (Lesson learned: Don’t point regular binoculars or telescopes toward the Sun. Even if you aren’t looking through the lenses, the focused light could cause a fire.)
Clearly, it’s important to take precautions whenever you’re viewing an eclipse or a transit. That’s one reason that Morehead Planetarium and Science Center is planning a special family science event for the upcoming Transit of Venus on June 5.
It’s free, and it provides lots of different ways for you to view the transit safely:
- Eclipse glasses
- “Solar telescopes” that have special filters
- Planetarium mini-shows that illustrate the transit
- Live transit video images
The event includes presentations by NASA Solar System Ambassadors and hands-on activities for children, too.
Save your vision! View the transit safely with Morehead Planetarium and Science Center on June 5. And if you choose to view the transit from home, please remember: “Safety First” whenever you view a transit or eclipse.
Disclaimer: No eyes were melted during the making of this "what not to do" demonstration.