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Safely Viewing the Solar Eclipse

June 2017

Safely Viewing the Solar Eclipse

Academy Fellows routinely educate patients, students, friends and family on various eye- and vision-related topics of interest. One topic that will attract significant attention this summer: the first total solar eclipse in the continental United States in 38 years! On August 21st, there will be a perfect lineup of the sun, moon and Earth. Those in the path of the umbral shadow will see one of nature’s most spectacular shows in the daytime skies.1

This eclipse is predicted to be the most-viewed ever.1 The attention it will get from the media, the superb coverage of the highway system in our country, the typical weather on that date, and the vast number of people who will have access to it from nearby large cities contribute to this prediction.

The first place in the continental U.S. to catch a view of the total eclipse will be the waterfront at Government Point, Oregon, at 10:15:56.5 a.m. PDT.1 There, the total phase will last 1 minute, 58.5 seconds. After a great west-to-east path across Oregon, the moon’s umbral shadow takes roughly nine minutes to cross a wide swath of Idaho. The center line then will move through Wyoming, Nebraska, Illinois, Missouri, Kentucky Tennessee, North Carolina, Georgia, then South Carolina.1,2

Only one large city in the U.S. will have a great view.1 If you’re one of the 609,000 people lucky enough to live in Nashville, you’ll have a great view. The city center and parts north of it will experience 2+ minutes of totality. Unfortunately, that’s the only large city with a great view.

The totality of the eclipse will last 2 minutes and 40.2 seconds, so if you are traveling to watch the eclipse, don’t be late!  If you plan on watching, you won’t need a telescope. One of the great things about a total solar eclipse is that it looks best to naked eyes.1 Nevertheless, binoculars when used safely can give a close-up view.

As we anticipate the magnificent solar eclipse event that is taking place in a short few weeks, a safety reminder is in order. The American Astronomical Society has issued a concise safety alert flyer on viewing the eclipse that might be helpful.2 One of our esteemed Fellows, Dr. Ralph Chou, was instrumental in composing the alert. Note that the advisory has been endorsed by our Academy and by several additional organizations including the American Academy of Ophthalmology, the American Optometric Association, the American Astronomical Society, the National Science Foundation, and the National Aeronautics and Space Administration, to name a few. A technical report with much more detail is also available.3

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. This will happen only within the narrow path of totality. To find out whether your home or any other specific location is within the path on August 21, 2017, see Xavier Jubier’s Google Map, which supports zooming in to street level.3

Here are a few key safety tips for your patients:4

  • The only safe way to look directly at the uneclipsed or partially eclipsed sun is through special-purpose solar filters (“eclipse glasses” or handheld viewers) that meet the ISO 12312-2 international standard for such products.
  • Homemade filters or ordinary sunglasses, even very dark ones, are not safe for looking at the sun.
  • Seek expert advice before using a solar filter with a camera, telescope, binoculars, or any other optical device.
  • Never look at the Sun through an unfiltered camera, telescope, binoculars, or any other optical device while using eclipse glasses or a handheld solar viewer.
  • A solar filter must be attached to the front of any telescope, binoculars, or camera lens.
  • 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 the splendor of totality, then, as soon as the bright sun begins to reappear, replace your solar viewer to glance at the remaining partial phases.
  • Outside the path of totality, you must always use safe solar filters to view the sun directly.

REMEMBER: Looking directly at the sun, even when it is partially covered by the moon, can cause serious retinal damage. So, NEVER look at a partial solar eclipse without proper eye protection.

I hope this information helps to remind all of us how important it is to warn our patients about the potential risks that are associated with looking at the sun, and in particular, the harm that may accompany viewing this eclipse without taking precautions. It’s essential to provide accurate information on this topic since misinformation may be devastating. Please share these recommendations with your patients, friends and family.

Special thanks go out to Dr. Ralph Chou and his team for the sage advice on viewing the solar eclipse safely and for the technical review of this month’s President’s Calling.

Sincerely,

Joseph P. Shovlin, OD, FAAO
President, American Academy of Optometry