On May 20th, northern California will be treated to an eclipse of the Sun as the moon’s shadow sweeps across the Earth. Best views of the event will be a bit north of Davis, closer to Redding where a total eclipse should be visible. The eclipse will begin about 6.20 pm Pacific Time and last for about four minutes.
This is an annular not a total eclipse, so even in the best location, a rim of the Sun will be visible around the Moon. That’s because the size of the Moon’s shadow varies a bit depending on the exact distance between the Earth and Moon.
“Eclipses are like the birth of a baby — they come with much anticipation and excitement, but may require special equipment, are all different, and the differences are usually important,” said UC Davis opthmalologist Ivan Schwab.
“This can be fun, but it does mean a bit of warning. It means that from Sacramento or Davis, an observer will never see a complete eclipse. It is never safe to view the sun partially eclipsed without protective eye wear,” Schwab said in an email. “Eclipse glasses can be worn and the eclipse can be safely viewed with these.”
As it happens, the UC Davis Geology Club is selling certified eclipse-viewing glasses at $2 a pair, three pairs for $5. If you want to order in bulk, further discounts are available, according to club co-president Kevin Delano. The club will deliver bulk orders in the Davis area, Delano said.
You can also use the glasses to view another, rarer astronomical event — the transit of Venus on June 5th, when the planet Venus will cross the Sun (from our point of view). The next transit of Venus will not occur until 2117.
To order glasses, contact Savannah Lisle, firstname.lastname@example.org. Proceeds go to the Geology Club.
Do NOT attempt to view the Sun through pinhole glasses, regular sunglasses or other makeshift glasses, Schwab warned.
“Don’t play with the potential of visual damage,” he said.
The Geology Club is not planning an event, Delano said, but does have information on where to go to best see the eclipse (Redding, Tahoe, Chico). However, geology professor Qing-Zhu Yin is giving a public talk on the Lotus Valley meteorite in Coloma on the evening of May 20, and an eclipse viewing will be held outside the venue immediately beforehand.
(Annular eclipse image from NASA Hinode satellite)