Protect your eyes during Monday's rare total solar eclipse

The use of regular sunglasses will not safeguard your vision; use approved "eclipse glasses"

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      Monday's (August 21) total solar eclipse will be the first one to be visible in the continental U.S. in decades. Although its path of totality will be relatively narrow (less than 150 kilometres) and pass through parts of only 14 states—from coastal Oregon at 9:05 a.m. (PDT) to South Carolina at 2:44 p.m. (EDT)—it will still have about an 86-percent totality here in Vancouver at 10:21 a.m.

      NASA illustrations

      Although you should never normally look directly at the sun without some kind of eye protection, this advice is even more important during a total solar eclipse because of the danger of permanent eye damage.

      Normally, blinking and pupil constriction reduce the amount of light that hits your eyes in very bright conditions, usually causing you to look away or shield your face. In the darkened conditions of a total solar eclipse, however, those defensive behaviours are curtailed and your eyes can stay open longer without discomfort for extended periods.

      However, even though visible light is greatly reduced during a solar eclipse, eyes are still being exposed to dangerous infrared and ultraviolet radiation.

      This is when damage can occur—even a few seconds of unprotected exposure to the sun's "corona" can cause solar retinopathy, which can result in permanent blind spots or blurry patches in your sight—and is the reason why those who plan on watching the eclipse need to look through approved safety glases, sometimes marketed as "eclipse glasses". (Severe and lengthy exposure without protection can even result in blindness.)

      Never look at a solar eclipse through regular sunglasses, however dark they may be, or binoculars, or any kind of camera, or telescopes (except where proper solar filters can be applied, as in at an observatory).

      Eclipse glasses must be used at all times when looking at any visible part of the sun during an eclipse. The only time they can be taken off is during the relatively brief totality phase, when the sun is completely hidden, but that will not happen in Canada (and only usually lasts between one and two minutes).

      Even when using eclipse glasses, continuous viewing should be limited to three minutes. All children using the glasses should be rigorously monitored.

      Unfortunately, when contacted by the Straight, London Drugs, Best Buy, and Costco said they were out of stock when asked about eclipse glasses. Walmart's customer-service line went unanswered despite numerous contact attempts Thursday evening (August 17).

      Welder's glass that is Shade 12 or above is safe for watching, but you must be sure of the number. There are also numerous simple "pinhole"-style devices that can be constructed to safely indirectly view the eclipse as a projection upon the ground or a flat surface. These methods can be easily looked up on various websites.

      In addition, some websites will be streaming the eclipse live.

      Observatories often provide safe methods for viewing total solar eclipses.

      In Vancouver, the H.R. MacMillan Space Centre will be holding a community eclipse-watching celebration on the lawn outside of the Gordon Southam Observatory on Monday, starting at 8:45 a.m. and running until noon. Safe solar telescopes and sun projections will also be made available, as well as "special eclipse-themed shows and activities".

      Admission is by donation and includes—while supplies last—a pair of certified eclipse glasses.

      So have fun and enjoy—and watch—the total solar eclipse safely. There won't be another one visible from here for another 18 years.