On Monday, Aug. 21, 2017, a solar eclipse will be visible across North America (weather permitting). 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 will experience a brief total eclipse. At that point, the moon will completely cover the face of the sun for up to 2 minutes 40 seconds.
Here's a table with times for a handful of U.S. cities and towns in the path of totality, courtesy of NASA:
In order to have a total eclipse of the Sun on August 21, 2017, you must position yourself within the roughly 70-mile-wide track of the cities mentioned above or in this path:
Within the path of totality, weather permitting, you will see one of the most spectacular sights in all of nature: the solar corona — the Sun's pearly outer atmosphere, which you can look at directly without solar filters or other protective measures.
Outside the path of totality, you will see at most a partial solar eclipse, and only if you take special precautions to avoid eye injury. The only safe way to look directly at the un-eclipsed or partially eclipsed Sun is through special-purpose solar filters, such as “eclipse glasses” 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. Eclipse glasses and handheld solar viewers must be compliant with the ISO 12312-2 international safety standard for such products.
Some (not all) locations in the following retail chains sell ISO-compliant safe eclipse glasses and/or handheld viewers in their stores, but not on their websites. 7-Eleven, Best Buy, Circle K, Hobby Town, Kirklands, Kroger, Lowes, Pilot/Flying J, Toys "R" Us, and Walmart.
Instructions for safe use of solar filters/viewers:
- Always inspect your solar filter before use; if scratched, punctured, torn, or otherwise damaged, discard it. Read and follow any instructions printed on or packaged with the filter.
- Always supervise children using solar filters.
- If you normally wear eyeglasses, keep them on. Put your eclipse glasses on over them, or hold your handheld viewer in front of them.
- 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 devices.
- Similarly, do not look at the Sun through a camera, telescope, binoculars, or any other optical device while using your eclipse glasses or handheld solar viewer — the concentrated solar rays could 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, 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 inside the path of totality, 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.
An alternative method for safe viewing of the partially eclipsed Sun is indirect via pinhole projection. Note that pinhole projection does not mean looking at the Sun through a pinhole! You project sunlight through the hole onto a surface and look at the solar image on the surface.
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.
Enjoy this spectacular event and use safety precautions. You only have TWO eyes and they need to last a lifetime. Please share this information with your family, neighbors and company associates............Thank you, Isabel