Solar Eclipse
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.