Update Mar 21: Some spectacular Super Moon photos on Flickr.
An unusually large looking "super moon" will rise Saturday evening, the biggest in 18 years.
Full moons vary in size because of the oval shape of the moon's orbit. This Saturday the moon will be closer to the earth than at any time since 1993. NASA scientists say that such perigee moons appear 14 percent bigger, and 30 percent brighter.
Reporter Kelly Wilkinson spoke with Ben Burress, the staff astronomer at Chabot Space and Science Center. He says the best time to view the moon is when it rises at 7:45 p.m. Saturday...if the rain holds off.
"I'm not holding out much hope that the moon will make an appearance. But there’s always that possibility," Burress said. "Maybe we'll get a part in the clouds at just the right moment."