Three concession workers in Yellowstone National Park decided to float down the Lamar River the other day in tubes, but only two made it to shore. The third was swept down the Yellowstone River and hasn't been found.

How much should the National Park Service rely on volunteers? That's a difficult question, as there are teachers, retirees, and others with valuable knowledge and skills that the parks could benefit from, particularly as the agency struggles to make ends meet. But does Apple, or JP Morgan, or any Fortune 500 company rely as much on volunteers for day-to-day operations as does the Park Service?

Parks, especially those in locations with minimal night sky distractions from artificial light, can be great locations for observing—and photographing—celestial events such as Monday's so-called Super Moon. A number of parks offer special night sky programs, but your opportunities to enjoy those out-of-the-world scenes aren't limited to organized events. As the photo accompanying this story confirms, the right locale and timing can provide a chance for a super photo.

National park travelers are keenly aware of the changing seasons. The Blue Ridge Parkway is a completely different experience in August than in October. The hoodoos of Bryce Canyon need to be seen both in the blistering July sun and the January snow to be fully appreciated. And, of course, there’s Yellowstone – a bustling city on a summer weekend and a tranquil white wilderness on a bright February morning.