A partial eclipse of the sun on Thursday. Will any

It’s solar eclipse time again — but this week’s won’t be total.
The new moon will blot out nearly half the sun’s surface in a partial solar eclipse Thursday afternoon. And because it’s partial, the eclipse will not turn daylight into night, but if the skies are clear, the phenomenon should be visible in telescopes throughout the Bay Area.
As it passes across the sky Thursday, the new moon will slowly move between the Earth and the sun from 1:52 p.m. until 4:32 p.m., covering at most about 40 percent of the solar surface, astronomers have calculated.
The best time to see it will be about 3:30 p.m. Pacific time. That’s when it will be at its maximum in the Bay Area, said , the lead astronomer at in Los Altos Hills.
“But it’s extremely dangerous to watch any solar eclipse without proper eye protection,” he said. “Even a brief look at the sun can cause blindness. Dark sunglasses, smoked film or a camera lens are no help, he said, but special solar glasses available cheaply at many science stores like the Exploratorium and the in San Francisco are exactly right.
In a total solar eclipse, the moon’s passage across the sun’s face blots out every bit of sunlight; the sky becomes dark and the stars emerge. But during Thursday’s partial eclipse, the shadow of the moon won’t completely cover the sun’s surface, meaning plenty of sunlight will remain throughout the eclipse.
“Thus most people will not even notice that the eclipse is going on,” Fraknoi said.
An eclipse of the sun — partial or total — can only occur during the new moon each month, said retired NASA astrophysicist , a noted eclipse specialist. At least twice a year, the passage of the moon and Earth in their orbits around the sun line up, so that some part of the moon’s shadow falls somewhere on the Earth’s surface and an eclipse of the sun becomes visible in that region, Espenak explained.
Thursday’s eclipse will not be total anywhere on Earth, but the partial eclipse will be visible across all of North America.
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Partial eclipse
A dozen science museums, observatories and amateur astronomy organizations throughout the Bay Area will be holding eclipse parties for the public Thursday — generally between 2 p.m. and 4:30 p.m. Professional and amateur astronomers with solar telescopes will describe the progress of the eclipse and explain the phenomenon. Here are some:
, 1600 Holloway Ave. at the south entrance to .
The California Academy of Sciences in Golden Gate Park, on the museum’s Living Roof and in the West Garden.
The Foothill College Observatory, 12345 El Monte Road, Los Altos Hills.
The College of San Mateo Observatory, 1700 W. Hillsdale Blvd. in San Mateo.
The of Science, Centennial Drive in Berkeley.
The Chabot Space Science Center, 10000 Skyline Blvd., Oakland.
The Children’s Natural History Museum, 4074 Eggers Drive, Fremont.
in Larkey Park, 1931 First Ave., Walnut Creek, with members of the Mount Diablo Astronomical Society.
San Carlos Library, 610 Elm St., San Carlos, with members of the San Mateo Astronomical Society.