During Solar eclipse, the moon passes between the sun and Earth and blocks all or part of the sun for up to about three hours, from beginning to end, as viewed from a given location. For this eclipse, the longest period when the moon completely blocks the sun from any given location along the path will be about two minutes and 40 seconds.
Everyone in the United States, in fact, everyone in North America plus parts of South America, Africa, and Europe will see at least a partial solar eclipse, while the thin path of totality will pass through portions of 14 states.
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 hand-held solar viewers. Homemade filters or ordinary sunglasses, even very dark ones, are not safe for looking at the sun.
To date five manufacturers have certified that their eclipse glasses and handheld solar viewers meet the ISO 12312-2 international standard for such products:
- American Paper Optics,
- Baader Planetarium (AstroSolar Silver/Gold film only),
- Rainbow Symphony,
- Thousand Oaks Optical, and
- TSE 1
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