From eclipse.aas.org
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, which 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.
The only safe way to look directly at the uneclipsed or partially eclipsed Sun is through special-purpose solar filters, such as “eclipse glasses” (example shown at left) or handheld solar viewers. Homemade filters or ordinary sunglasses, even very dark ones, are not safe for looking at the Sun; they transmit thousands of times too much sunlight. See our Reputable Vendors of Solar Filters & Viewers page for a list of manufacturers and authorized dealers of eclipse glasses and handheld solar viewers verified to be compliant with the ISO 12312-2 international safety standard for such products.
Instructions for safe use of solar filters/viewers:
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