On Thursday night into early Friday morning, residents in the Bay Area will be able to witness a spectacular total lunar eclipse — often called a “blood moon” due to its deep red hue.
This celestial event happens when the Earth moves directly between the sun and the moon, casting a shadow that darkens the moon and turns it into a striking shade of red during totality. And unlike solar eclipses, which require special glasses, you can enjoy the lunar eclipse with the naked eye.
The last time a total lunar eclipse was visible from North America was just two years ago, in November 2022. “These total eclipses of the moon happen much more frequently than the total eclipses of the sun at any given location because you can see the full moon all over part of the Earth,” said Andrew Fraknoi, astronomer and professor at the University of San Francisco’s Fromm Institute.
A lunar eclipse is visible to anyone on the night side of Earth. In contrast, total solar eclipses are only visible along a narrow path of totality — sometimes just a few hundred miles wide.
This upcoming total lunar eclipse will be fully visible across the Bay Area tonight as long as you have a clear view of the moon.
It will begin at around 10 p.m. P.S.T. on Thursday, March 13, and totality will occur at 11:26 p.m. The maximum eclipse — when the moon will be its reddest — will occur at 11:59 p.m. and last for about 30 minutes into the early hours of Friday, March 14.
The whole eclipse phase will last for about 64 minutes, from 10 p.m. to 1:47 a.m., with the best views occurring between 11:26 p.m. to 12:31 a.m.
“As the moon moves slowly through the Earth’s shadow, we first see only part of the moon darkening,” Fraknoi said of the partial eclipse. “But then, as the Moon moves fully into the Earth’s shadow, we see its entire disk of the Moon become dark and reddish.”
During totality, the moon glows red because of Rayleigh scattering, the same phenomenon that makes sunsets appear orange and red. As sunlight passes through Earth’s atmosphere, it filters out blue light and bends red light toward the moon, giving it that signature “blood” color.
The exact shade of red depends on atmospheric conditions like dust, pollution and volcanic activity elsewhere, which can intensify the red hue, Fraknoi said.
Astronomers have used calculations to predict lunar eclipses for centuries. “It’s a really nice indication that even if things are in turmoil on Earth, the heavens are doing their thing in a routine way,” Fraknoi said.
“It shows the clockwork motion of the heavens.”
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