Safe eclipse viewing tips
“There are risks of viewing the eclipse without any eye protection,” warns Nathan Podoll, M.D., assistant professor of Ophthalmology and Visual Sciences. “Normally if you look directly at the sun, the natural response is to squint, shield your eyes, blink or turn away.
“The concern with the eclipse is that when it is in the partial phase, the natural reflex to shy away from looking at the sun is reduced, and that is dangerous because of the possibility of developing solar retinopathy, which can occur without the person knowing it,” he said. “In addition, the retina has no pain receptors so damage can occur before someone realizes.”
Podoll added, “In most cases retinal damage will result in blurred vision or the presence of blind spots. An eye care specialist will be able to determine the level of damage upon examination.”
Podoll offers eyewear tips for safe eclipse viewing:
· Make sure to wear proper ISO-approved protective eyewear — eclipse glasses filter out harmful rays and make it safe to view all phases of the eclipse.
· Make sure the lenses are made of black polymer material. While wearing a pair of undamaged glasses (ones that are not scratched, torn or with holes) you shouldn’t be able to see anything except the mild glow of the sun when looking toward the sun.
· Proper protective eyewear can be worn over regular prescription glasses.
· Do not use lenses or glasses if light penetrates through tiny pinholes or scratches have developed.
· A shade No. 14 welding glass is suitable for viewing.
Alternative viewing method
There are alternative methods to indirectly view the partially eclipsed sun. NASA suggests the following: cross the outstretched, slightly open fingers of one hand over the outstretched, slightly open fingers of the other. 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.
Other options include: Craft a pinhole viewer to project the image onto another surface. Place a pinhole or small opening in a card. Other suggested ready-made pinholes include a colander, strainers, pegboards or anything with really small holes. Hold the object between the sun and a white surface, like a piece of paper or the sidewalk, to see an image of the sun on the screen.
Never view an eclipse:
With the naked eye except during totality when the sun is completely covered by the moon. You must use proper eye protection (e.g., solar eclipse glasses) to view the partial solar eclipse phase, which lasts for approximately 1.5 hours before totality and after totality. During the total solar eclipse, when the sun is completely obscured by the moon, solar glasses will need to be removed to view with the naked eye. The sun’s corona, which is safe to observe with the naked eye, cannot be observed with solar glasses on, as it is only about as bright as a full moon.
Never view an eclipse:
· Through darkened sunglasses
· Looking through a window in a home or car
· Using smoked glass
· Using exposed photographic or x-ray film
· Through an unfiltered telescope, binocular or camera lens
· Using a sun filter on a telescope. One can observe the PARTIAL phase of the solar eclipse with a telescope that is equipped with the proper solar filter at the front end so that the light is filtered before it enters the telescope. It is not recommended to view the total solar eclipse telescopically as this requires removal of the solar filter and puts one at risk of serious eye damage because the exact moment when the sun begins to re-emerge from behind the moon is not known.