The ancients called them "wanderers." We know them as planets, and, according to the textbooks, Pluto is the most distant of the nine orbiting the star we call the sun. Or is it? In 2002, a team working at California's Palomar Observatory discovered an even more distant world. Named Quaoar, it's about half the size of Pluto, and until recently was hidden in the dark and frigid belt of cosmic icicles known as the Kuiper Belt.

Could there be something even larger hidden in this field? Could there be perhaps 100 billion Kuiper Belt Objects? Finding out will be one of the top quests for QUEST. Newly installed at the Palomar Observatory's Oschin Telescope near San Diego, and designed and built by astrophysicists from Yale and Indiana universities, the Quasar Equatorial Survey Team is the world's largest astronomical digital camera. It uses an array of 112 charge-coupled devices (CCDs) rather than conventional photographic film to scan the sky. Not only are these CCDs more sensitive to light than photographic film, they're also able to deliver data immediately, allowing researchers around the world to share QUEST's vision in real time.

Digital imaging has been around for a while in astronomical circles. It has already replaced photographic film at Oschin's neighbor, the 200-in. Hale Telescope. An earlier system, known as NEAT, or the Near-Asteroid Tracker, was temporarily installed at the 48-in. Oschin, and proved its mettle by uncovering 20 comets, 189 near-Earth asteroids--and Quaoar. But until now, the largest astronomical camera had only 30 CCDs. So with QUEST, researchers will not only gain a more sensitive tool, but one that can scan a much wider region of the sky.