2017 Solar Eclipse –
On Monday, Aug. 21, 2017, the U.S. will be treated to a total eclipse of the sun.
The eclipse will be visible — weather permitting — across all of North America. The entire continent will experience a partial eclipse lasting two to three hours. Anyone within a 70-milewide path that stretches through 14 states from Oregon to South Carolina will experience a total eclipse. During those brief moments — when the moon completely blocks the sun’s bright
face for about two minutes — day will turn into night, making visible the otherwise hidden solar corona, the sun’s outer atmosphere. Bright stars and planets will become visible as well. Birds will fly to their nighttime roosts. Nocturnal insects such as cicadas and crickets will buzz and chirp.
For NASA, the eclipse provides a unique opportunity to study the sun, Earth, moon and their interaction, because of the eclipse’s long path over land coast to coast. Eleven NASA and NOAA satellites, the International Space Station, more than 50 high-altitude balloons, and hundreds of ground-based assets will take advantage of this rare event over 90 minutes, sharing the science and the beauty of a total solar eclipse with all. Via live streams and a NASA TV broadcast, NASA will bring the Aug. 21 eclipse live to viewers
everywhere in the world.
• 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 looking 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
• 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
• Seek expert advice from an astronomer before using a solar filter with a camera, a telescope, binoculars, or any other optical
device. Note that solar filters must be attached to the front of any telescope, binoculars, camera lens, or other optics.
• 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 look at the remaining partial phases.
• Outside the path of totality, you must always use a safe solar filter to view the sun directly.
• If you normally wear eyeglasses, keep them on. Put your eclipse glasses on over them, or hold your handheld viewer in
front of them.
Note: If your eclipse glasses or viewers are compliant with the ISO 12312-2 safety standard,
you may look at the uneclipsed or partially eclipsed Sun through them for as long as you wish.
Furthermore, if the filters aren’t scratched, punctured, or torn, you may reuse them indefinitely.
Some glasses/viewers are printed with warnings stating that you shouldn’t look through them
for more than 3 minutes at a time and that you should discard them if they are more than 3
years old. Such warnings are outdated and do not apply to eclipse viewers compliant with the
ISO 12312-2 standard adopted in 2015. To make sure you get (or got) your eclipse glasses/
viewers from a supplier of ISO-compliant products, see the American Astronomical Society
(AAS) Reputable Vendors of Solar Filters & Viewers page.
An alternative method for safe viewing of the partially eclipsed sun is pinhole projection. For example, cross the outstretched, slightly
open fingers of one hand over the outstretched, slightly open fingers of the other, creating a waffle pattern. With your back to the sun,
look at your hands’ shadow on the ground. The little spaces between your fingers will project a grid of small images on the ground,
showing the sun as a crescent during the partial phases of the eclipse. Or just look at the shadow of a leafy tree during the partial
eclipse; you’ll see the ground dappled with crescent Suns projected by the tiny spaces between the leaves.
A solar eclipse is one of nature’s grandest spectacles. By following these simple rules, you can safely enjoy the view and be rewarded
with memories to last a lifetime.