Friday, May 18, 2012

Solar eclipse is steller opening act for big show in the sky

Sunday's partial solar eclipse is only the start

David Perlman - San Francisco Chronicle - May 18, 2012

The sun, the moon and the planet Venus will be staging shows during the next two weeks with three astronomical events in the springtime sky.

The first will be a rare type of partial solar eclipse on Sunday, followed in the days afterward by a partial lunar eclipse and the rare sight of Venus crossing the face of the sun in what astronomers call a transit.

The eclipse will begin at 5:16 p.m. Sunday when the new moon moves slowly across the sun's face and blocks most of it, providing a spectacular event for Bay Area viewers with proper eye protection. The National Weather Service forecasts a sunny, breezy late afternoon.

The eclipse will peak in the Bay Area at 6:33 p.m., when 84 percent of the sun will be obscured by the moon's passage, said astronomer Andrew Fraknoi of Foothill College and the Astronomical Society of the Pacific.

Ring of fire

Farther north, the event will be seen as a rare "annular" eclipse, occurring when the moon's passage carries it almost completely in front of the sun. For a few seconds, a brilliant ring of sunlight - a "ring of fire," as astronomers call it - will appear around the darkened lunar disk.

The annular eclipse - from the Latin word annulus, for "ring" - should be clearly visible in cities like Chico, Redding and Eureka as well as the region across California roughly between Yuba City and Yreka, according to calculations by Fred Espenak, a solar eclipse specialist at NASA's Goddard Space Flight Center in Greenbelt, Md.

All eclipses, including this one, are dangerous if viewed with the naked eye, or even with the darkest available sunglasses, and Fraknoi warns that doing so can cause blindness.

Safe viewing

Many science institutions and amateur astronomers
 in Northern California
will be setting up special viewing sites, equipped with safe solar telescopes as well as instruments designed to watch the eclipse indirectly.

For Bay Area residents,
the best time to watch
the eclipse will be
between 6:15 and 6:45 p.m., Fraknoi said.

But, he said, "you'll have to find an open location where you can see things that are lower on the northwest horizon, making sure that hills or buildings don't get in the way."

The eclipse will end over the Bay Area at 7:40 p.m.

The second celestial show will be June 4, during the full moon, when Earth will cast its shadow on the moon's face, blocking out more than 35 percent of the moonlight. But, to see it, eclipse watchers will have to stay up late or wake up early: The eclipse will begin in the Bay Area at 2:59 a.m. and end at 5:06 a.m.

Finally, during the afternoon of June 5, sky watchers will see Venus crossing a corner of the sun in a rare transit. As with the eclipse, viewers are advised to be equipped with safe solar viewing telescopes, or black welder's glasses or indirect viewing instruments. Local time for the event will be from 3:06 p.m. to 3:24 p.m., according to Espenak's calculations.

Watching the eclipse

Here is a partial list of Bay Area sites where the public can view Sunday's solar eclipse using safe solar telescopes and other instruments. Peak viewing times will be between 6:15 and 6:45 p.m.

San Francisco

-- The California Academy of Sciences in Golden Gate Park, from 5 to 7:40 p.m, on the Music Concourse entrance.

-- Marina Green at the end of Marina Boulevard and Yacht Road, from 5 to 8 p.m., hosted by members of the San Francisco Amateur Astronomers.

-- Sunset Reservoir Park, on the path above 28th Avenue and Ortega Street, from 5:15 to 7:30 p.m., sponsored by members of the San Francisco Sidewalk Astronomers.


The Lawrence Hall of Science, 1 Centennial Drive, on the main plaza, from 5 to 8 p.m. A special eclipse program will be held simultaneously in the hall's planetarium.


The Chabot Space and Science Center's observatory deck, 10000 Skyline Blvd., 5 to 8 p.m.

San Carlos

The San Carlos library, 610 Elm St., from 4 to 7 p.m.

Los Altos

The Foothill College Observatory, 12345 El Monte Road, in and outside the dome, from 5:30 to about 7:30 p.m., hosted by members of the Peninsula Astronomical Society.


The Albany Community Center, 1249 Marin Ave., between 4 and 7 p.m. Telescopes will be at the rear.

Pleasant Hill

The Diablo College Observatory from about 5 p.m. until the sun goes behind the trees.


Juniper Campground parking area, from 5 to 7:30 p.m., hosted by the Mt. Diablo Astronomical Society.

San Jose

The intersection of Twilight and Rupert drives, from 5 to 7:40 p.m., sponsored by the San Jose Astronomical Association.

Mount Hamilton

The Lick Observatory, beginning at 5 p.m.


David Perlman is a San Francisco Chronicle science editor.


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