You might not entirely appreciate the wonders and majesty of national parks unless you venture out after dark and gaze up at what often is referred to as the other half of the national park system. The view can be quite dazzling, with planets, stars, the Milky Way, and for the lucky, a comet or shooting star.

Sadly, not every park offers such dazzling views. Light pollution reaches more than a few national parks, and can really infringe on your nighttime enjoyment of the parks.

Gavin Heffernan is among those park travelers who are troubled by light pollution. He's a California-based photographer with a unique long-form time lapse style. And he's hoping this approach brings a fresh awareness to the wonders of night skies in the national parks and creates advocacy to fight light pollution and the damage it wreaks on natural habitats.