There's a different kind of depth to the darkness at nighttime in the upscale Catalina Foothills neighbourhood of Tucson, Arizona. Lights are limited by both the county and the homeowners' association; they must be shielded and can only face down, a deliberate effort to maintain Tuscon's "dark sky" status - designed to minimise light pollution, reduce energy waste and protect astronomical research at nearby facilities. The result is a quiet, peaceful blackness making Catalina Foothills the