A rainbow above a lone Valley Oak (Quercus lobata). You might even be able to pick out a trace of the second rainbow up on the right. We and the tree are in sunlight; raindrops fill the sky beyond. (A polaroid filter enhances the rainbow -- the rainbow light is polarized.) Jasper Ridge Biological Preserve, near the intersection of Trail 16 and Road F, 4/26/2012, 8:34 am.