For two fleeting minutes on Monday, day will turn into night in a roughly 70-mile-wide strip of land spanning the U.S. diagonally, from Oregon to South Carolina.
The temporary “sun outage” in select urban and rural parts of the U.S. can be attributed to the moon casting its shadow onto Earth — traveling for the first time in nearly a century across the country coast to coast — in what star enthusiasts and astronomers have dubbed the “Great American” total solar eclipse.
A total solar eclipse occurs when the Earth, sun and moon align in such a way that, to earthly viewers, the sun is completely blocked out by the moon, according to Joseph Barranco, associate professor and theoretical physicist at San Francisco State University.
He promises Monday’s eclipse to be quite spectacular.
“The sky will go completely dark and you will see stars [in the middle of the day],” said Barranco, adding that within the eclipse’s path, known as the path of totality, temperatures are expected to drop by as much as 10 degrees.
“You feel it plummet. It will feel … like it’s actually night time,” he said.
In the Bay Area, the solar eclipse, though highly anticipated, is unlikely to shake out with the same “end-of-the-world” semblance, said Barranco.
To everyone outside of the eclipse’s path of totality, the eclipse will only be visible as partial, causing the world to dim slightly at best.
That is, if Karl the Fog doesn’t get in the way.
Anna Schneider, a meteorologist with the National Weather Service, advised those who are serious about viewing the eclipse to leave notoriously foggy neighborhoods or travel outside of The City as a precautionary measure.
“Right now we have it as cloudy along the coast. Your best bet are higher elevations or inland,” she said.
Unlike the two-minute total blackout that will be visible in the eclipse’s path of totality, a partial eclipses’ dimming can last for hours. In San Francisco, the partial eclipse is set to begin at 9:01 a.m. and reach its maximum at 10:15 a.m.
“That’s when the biggest bite is taken out of the sun,” said Andrew Fraknoi, chair of the Astronomy Department at Foothill College in Los Altos Hills, adding that 76 percent of the sun will be covered, or three-fourth’s of the of the sun’s disc.
The last time the moon’s shadow stroked the continental U.S. was in 1979 — but a total eclipse was also visible in Hawaii in 1991. Fraknoi, was there.
“It’s the most beautiful, unearthly thing you can see,” said Fraknoi, who planned to make the pilgrimage to Oregon this weekend to view the eclipse from within the belly of totality.
Fraknoi is not alone.
“Astronomers and enthusiasts made reservations a year ago — the emergency management people in that zone are very worried that a million extra people will drive up there for the fun of it,” he said.
Fraknoi suggests that those interested in viewing the eclipse leave their homes between 10 a.m. and 10:30 a.m. By 11:37 a.m., the eclipse will be over.
Dispelling myths that the sun’s ultraviolet rays are more harmful during an eclipse than usual, both Barranco and Fraknoi cautioned that looking into the sun for an extended amount of time is never a good idea.
They suggested snagging a pair of solar viewing glasses, which can be purchased at department stores such as Lowe’s and Walmart, or are available for free but in limited supply at San Francisco and Oakland public libraries.
Everyday household items, such as a colander used to strain vegetables or a compact mirror, offer safe and cheap viewing alternatives.
Facing away from the sun during a partial eclipse and holding the colondar over one shoulder, the sun’s rays will cast a shadow with a “series of pin-hole images in it of the eclipsed sun” — in crescent shape — said Frankoi.
A compact mirror covered by a piece of cardboard with a dime-sized hole cut out of it, can also be held against the sun to catch “an image of the eclipsed sun reflected on a wall that is perfectly safe to look at.”
The latter, said Fraknoi, takes some practice. “It took me about 10 tries, you might want to practice over the weekend.”
The Great American solar eclipse can be viewed from various locations in San Francisco, including the Exploratorium and Civic Center Plaza.
Where to view the eclipse:
Pier 15, The Embarcadero & Green Street
9 a.m. to Noon
Public Solar Viewing with Mayor Ed Lee, the California Public Utilities Commission and Energy Upgrade California
Civic Center Plaza, across from City Hall at Polk Street
10 a.m. to 11 a.m
San Francisco Viewing Points
Hamon Observation Tower
50 Hagiwara Tea Garden Dr.
1705 14th Ave.
501 Twin Peaks Blvd.
Bernal Heights Park
3400 Folsom St.
Mount Davidson Vista Point
999 Rockdale Dr.