"Who says you can't take an interesting astro-photo under a full moon?" asks Larry Landolfi of Rochester, New Hampshire. In fact, he says, "you can," and as proof he offers this 3-hour exposure under the full Wolf Moon of Jan. 2nd.

The nighttime sky is blue! There's a simple explanation: The daytime sky is blue because molecules in the air scatter sunlight. The nighttime sky is blue because molecules in the air scatter moonlight. The physics is precisely the same. The blue of a moonlit sky is so faint, however, that a long exposure is required to reveal it.

Long exposures also make star trails--slow, graceful arcs traced by the stars as Earth spins on its axis. These are visible in Landolfi's photo, too.