During the Aug. 21 total solar eclipse, it will be dangerous to look at the sun before the moon completely covers its surface, according to our local affiliate WJLA.
“Damage to the eyes comes predominantly from invisible infrared wavelengths, according to NASA. “The fact that the Sun appears dark in a filter or that you feel no discomfort does not guarantee that your eyes are safe.”
Due to the harshness of the sun’s rays, human instinct usually causes a person to look away from the sun before any severe damage is done to the eyes. However, viewing the corona of the sun is safe-only when the eclipse reaches the point of totality. At any other time though (especially for those not in the path of totality) without proper eye protection - looking at the giant fireball could cause solar retinopathy.
NASA explains that there are several options for viewing the eclipse that can help protect your eyes from the damaging effects of the sun’s light and still witness the beauty of the eclipse.
Solar GlassesSolar glasses are equipped with special-purpose solar filters, which will protect your retinas from permanent damage and even blistering. NASA has collected and published a full list of approved manufacturers for solar glasses.
• American Paper Optics (Eclipser) / EclipseGlasses.com
• APM Telescopes (Sunfilter Glasses)*
• Baader Planetarium (AstroSolar Silver/Gold Film)* [see note]
• Celestron (EclipSmart Glasses & Viewers)
• DayStar (Solar Glasses)
• Explore Scientific (Solar Eclipse Sun Catcher Glasses)
• Lunt Solar Systems (SUNsafe SUNglasses) [see their unique kid-size eclipse glasses]
• Meade Instruments (EclipseView Glasses & Viewers)
• Rainbow Symphony (Eclipse Shades)
• Seymour Solar (Helios Glasses)
• Thousand Oaks Optical (Silver-Black Polymer & SolarLite)
• TSE 17 (Solar Filter Foil)*
If you choose to use solar glasses, be sure to inspect them properly, scratches, wrinkles and even minor damage can render the glasses ineffective and subject you to potential harm. Also, make sure that the ISO reference number 12312-2 is marked somewhere on the glasses.
For years, people used smoked glass to protect their eyes from the harsh rays of the sun. NASA now considers this and other homemade viewing methods unsafe. Even though these filters may appear dark, they can still subject the retina to damaging rays.
Even if you have an old pair of solar glasses at home, they are considered expired three years after their production date.
Sun glasses shouldn’t be considered a safe option for viewing the eclipse as they are not strong enough to fully protect the eyes.
“Sun glasses are doing something else, they make you look cool, they make your eyes not hurt when you’re at the beach but they cannot protect your eyes,” said Ivona Cetinic, NASA scientist with the Universities Space Research Association.
Pinhole ProjectorsNASA offers printable 2D and 3D templates for pinhole projectors on their website. The projectors are offered in the shape of states as well.
Pinhole projectors will cast a circle of light on to the ground and as the moon moves to cover the sun you will see a representation of the eclipse on the ground.
If you find yourself without a pinhole projector, you can use your hands to create a pinhole projection onto the ground.
“For example, 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.” NASA states.
Telescope, Camera or BinocularsBefore you attempt to view the eclipse through your home telescope, camera or binoculars NASA recommends speaking with an astronomer first.
You will need to attach a solar filter to the larger lens at the front of your telescope. “Never use small solar filters that attach to the eyepiece, as found in some older, cheaper telescopes,” NASA cautions.
The AAS breaks the solar filters into three types: metal on glass, aluminized polyester film or Mylar and black polymer. These filters can have different effects on the image, making the sun appear white, yellow orange or with a blue tint.
The organization even offers a buyer’s guide if you are not sure where to make your purchase.
If you plan on taking pictures of the eclipse, the American Astronomical Society’s guide is tailored to users of digital cameras.