Weather could cloud solar eclipse for North Bay skywatchers (w/video)

Sunlight won’t dim appreciably, but a partial solar eclipse will peak at 3:15 pm Thursday when the moon obscures 40 percent of the sun’s surface.

“It will seem like a normal day,” said Dr. Tom Targett, a visiting professor of astronomy at Sonoma State University.

If the National Weather Service’s forecast of a cloudy day with a 40 percent chance of rain in Santa Rosa proves accurate, folks here won’t see the astronomical phenomenon at all, he noted.

The verb “see” should be in quotes, as Targett and NASA officials are emphatic in warning that no one should attempt to look directly at the sun during an eclipse, or at any other time, without proper equipment.

SSU’s Department of Physics and Astronomy will provide that equipment - 500 pairs of dark glasses - at an eclipse viewing event open to the public at the campus observatory. Viewing will start at 1:51 p.m., with the first apparent contact between the moon and sun, and end about 4:32 p.m.

The day’s highlight, if it can be seen through a gap in the clouds, will be moon’s maximum coverage of the solar orb at 3:15 p.m. People can view it on their own with a telescope or binoculars equipped with a solar filter.

A solar eclipse occurs when the moon passes directly in front of the sun, blocking our view of all or part of the solar disk as the moon’s shadow falls on Earth. Since the moon orbits the Earth about once every 29 and a half days, solar eclipses are technically commonplace, but most of the time the moon shadow misses the Earth entirely.

The center of the moon’s shadow will pass above the North Pole Thursday, but the partial eclipse will be visible at sunrise in far eastern Russia and Japan and before sunset across most of North America.

Skies won’t darken as they do during a total solar eclipse, prompting abnormal behavior by some animals.

But the real deal - a total eclipse - is coming relatively soon, on Aug. 21, 2017, and although it won’t be visible in California, Targett said it will be on display “practically next door” in Utah, Wyoming, New Mexico and Colorado.

Total eclipses are actually fairly frequent, averaging one every two to three years somewhere on Earth, but most are visible only over the ocean or in remote spots like Siberia, he said.

In case of heavy cloud cover or rain, the viewing event at SSU’s observatory Thursday will be canceled.

The observatory is inside the stadium area at the southeast corner of the campus at East Cotati Avenue and Petaluma Hill Road. The event is free, but parking on campus is $5.

You can reach Staff Writer Guy Kovner at 521-5457 or guy.kovner@pressdemocrat.com.