Crepuscular rays

A few weeks ago I was walking home with Mrs. Bad Astronomer and the Little Astronomer after taking the Bad Dog to the park, and we had all remarked on how lovely the rising Moon was. The Sun was just at the horizon, the Moon was on the opposite side of the sky, nearly full, and the air around the Moon was reddish and pretty. As the sky darkened, I noticed a pattern of light and shadow pushing its way through the sky. It was low contrast, and it took me a moment to figure out what I was seeing, but then it snapped into place: crepuscular rays! These are the beams of light you can sometimes see fanning out from the setting Sun. The sunlight is broken up by mountains or clouds on the horizon in front of the Sun, and if the air is hazy enough you can see the beams superposed on the sky. It's common enough to see the rays coming from the sunset, but the sky has to be just right for the rays to reach all the way across the sky. It has to be hazy, but not too hazy or else the light gets absorbed, and the rays fade out. This night things were just so, and I could see the rays coming together opposite the Sun in the sky. I was able to get a picture: