On Monday, August 21, 2017, a solar eclipse will be visible (weather
      permitting) across all of North America. The whole continent will
      experience a partial eclipse lasting 2 to 3 hours. Halfway through
      the event, anyone within a roughly 70-mile-wide path from Oregon to
      South Carolina (https://go.nasa.gov/2pC0lhe) will experience a brief
      total eclipse, when the Moon completely blocks the Sun’s bright face
      for up to 2 minutes 40 seconds, turning day into night and making
      visible the otherwise hidden solar corona — the Sun’s outer
      atmosphere — one of nature’s most awesome sights. Bright stars and
      planets will become visible as well.

      The only safe way to look directly at the uneclipsed or partially
      eclipsed Sun is through special-purpose solar filters, such as
      “eclipse glasses” or hand-held solar viewers. Homemade filters or
      ordinary sunglasses, even very dark ones, are not safe for looking at
      the Sun. To date four manufacturers have certified that their eclipse
      glasses and handheld solar viewers meet the ISO 12312-2 international
      standard for such products: Rainbow Symphony, American Paper Optics,
      Thousand Oaks Optical, and TSE 17.

      Here are some points to remember to the view the solar eclipse
      safely:
            Always inspect your solar filter before use; if scratched or
            damaged, discard it. Read and follow any instructions printed
            on or packaged with the filter. Always supervise children using
            solar filters.
            Stand still and cover your eyes with your eclipse glasses or
            solar viewer before looking up at the bright Sun. After
            glancing at the Sun, turn away and remove your filter — do not
            remove it while looking at the Sun.
            Do not look at the uneclipsed or partially eclipsed Sun
            through an unfiltered camera, telescope, binoculars, or other
            optical device. Similarly, do not look at the Sun through a
            camera, a telescope, binoculars, or any other optical device
            while using your eclipse glasses or hand-held solar viewer —
            the concentrated solar rays will damage the filter and enter
            your eye(s), causing serious injury. Seek expert advice from an
            astronomer before using a solar filter with a camera, a
            telescope, binoculars, or any other optical device.
            If you are within the path of totality (
            https://go.nasa.gov/2pC0lhe), remove your solar filter only
            when the Moon completely covers the Sun’s bright face and it
            suddenly gets quite dark. Experience totality, then, as soon as
            the bright Sun begins to reappear, replace your solar viewer to
            glance at the remaining partial phases.