LOOKING DEEPER AND FARTHER

As astronomers trip over one another hunting for planets outside our solar system, some of the most exciting finds may be closer to home.
PALOMAR OBSERVATORY SURVEY

Since 1998, Mike Brown, Chad Trujillo of Gemini North Observatory, and astronomer David Rabinowitz of Yale University have used the 48-inch Samuel Oschin Telescope at Palomar Mountain in Southern California to scan the Kuiper belt and beyond for objects two-hundredths the brightness of Pluto. Every night, a mosaic of 112 CCD detectors snap digital images of a hand-size patch of sky. So far the search has turned up 35 bright objects. Over the next two years, the team plans to scan the entire northern sky.
DEEP ECLIPTIC SURVEY

A mosaic of eight CCD detectors coupled to the 3.8-meter Mayall Telescope at Kitt Peak National Observatory near Tucson, Arizona, scan for faint Kuiper belt objects as small as 30 miles in diameter. A second, identical camera is connected to the Blanco Telescope in La Serena, Chile. To date, the survey has spotted 411 objects. The goal, says survey leader Robert Millis, is to discover enough objects to begin to understand the scale of the belt, the three-dimensional distribution of objects in space, and their orbits.
SPACEWATCH

For a portion of each month, the 0.9-meter and the 1.8-meter telescopes at Steward Observatory on Kitt Peak scan the skies for comets, Earth-bound asteroids, and other small bodies in the solar system. Although the main quarry of Spacewatch is not Kuiper belt objects, astronomers did spot 560-mile-wide Varuna.
VERY WIDE SURVEY

Using the 3.6-meter Canada-France-Hawaii Telescope atop Mauna Kea in Hawaii and MegaPrime, the world’s most powerful astronomical camera, astronomers aim to discover and track the orbits of 1,000 Kuiper belt objects along the ecliptic. First results from the Very Wide Survey will be released in early 2005.

TAIWAN-AMERICAN OCCULTATION SURVEY

Astronomers are using four small robotic telescopes to simultaneously scan the same patch of sky. The telescopes look for the slight dimming of distant stars that occurs as nearer Kuiper belt objects momentarily occlude them. The hope is that objects as small as two miles wide will be detectable. The survey monitors 15,000 to 18,000 stars each night.