What is a solar eclipse?
A solar eclipse happens when the moon’s orbit passes in front of the sun, and the moon blocks some of the sun from view. A total solar eclipse means the moon fully blocks the sun. People in a 70-mile-wide path stretching from Salem, Ore., to Charleston, S.C., will experience a total solar eclipse on Aug. 21. Everyone else in the United States will be able to see a partially blocked sun. The last total solar eclipse visible in the United States was in 1979. The next will be in 2024.
When and where to see it
In Sacramento, the moon will start to cover the sun at 9:02 a.m. on Aug. 21. Maximum coverage, about 79 percent, will be at 10:17 a.m. The eclipse will be over at 11:39 a.m. You can see the eclipse anywhere with an unobstructed view of the sun. Make sure your view isn’t blocked by tall buildings or trees.
Protect your eyes when watching the eclipse
It’s dangerous to look at the sun with unprotected eyes. The intense radiation from the sun can damage your retinas. To watch the eclipse, get a pair of eclipse glasses. They can be purchased online, but make sure your glasses are up to the right standard – they should be marked ISO 12312-2. In Sacramento, they can be purchased at the Powerhouse Science Center’s gift shop. Don’t look at the sun through binoculars, telescopes or your camera’s viewfinder.
Look for weird shadows on the ground by trees. The spaces between the leaves act as “pinhole cameras” that project the image of the eclipsed sun on the ground. You can also see these projections by making a pinhole viewer or looking at the ground at light passing through the holes of a colander, cheese grater or even your crisscrossed fingers.
Umbra – The center of the moon’s shadow on Earth where a total eclipse is visible. The nearest area in the umbra to Sacramento is about 400 miles away along the totality path in Oregon.
Penumbra – The part of the moon’s shadow on Earth where a partial eclipse is seen. Sacramento falls in the penumbra of the Aug. 21 eclipse.
The chromosphere and corona – During a total eclipse, the moon blocks out the photosphere, the part of the sun we usually see that outshines the sun’s chromosphere and corona. For those on the totality path, the sun’s corona, or its outer atmosphere, appears like a filmy layer trailing off the sun’s surface. The chromosphere is the thin red layer encircling the sun.
What is a total eclipse like?
Here’s how it is described by David Baron in “American Eclipse: A Nation's Epic Race to Catch the Shadow of the Moon and Win the Glory of the World”:
“A total eclipse is a primal, transcendent experience. The shutting off of the sun does not bring utter darkness; it is more like falling through a trapdoor into a dimly lit, unrecognizable reality. The sky is not the sky of the earth – neither the star-filled dome of night nor the immersive blue of daylight, but an ashen ceiling of slate. A few bright stars and planets shine familiarly, like memories from a distant childhood, but the most prominent object is thoroughly foreign. You may know, intellectually, that it is both the sun and moon, yet it looks like neither. It is an ebony pupil surrounded by a pearly iris. It is the eye of the cosmos.”
- On Saturdays and Sundays in August before the eclipse: Powerhouse Science Center, 3615 Auburn Blvd. in Sacramento, has several eclipse-centered activities including hands-on demonstrations, lessons on making eclipse viewers and eclipse-themed planetarium shows. Learn more about the sessions at http://powerhousesc.org/eclipse/.
- The U.S. Postal Service dedicates its eclipse stamp at Powerhouse Science Center at noon Aug. 19.
- Powerhouse Science Center and the Sacramento Valley Astronomical Society are hosting an eclipse observation at Powerhouse Science center at 9 a.m. Aug. 21.