Astronomers think that near-Earth Asteroids the size of apartment
blocks number in the millions. And yet they spot new ones at the rate of
only about 30 a year because these objects are so faint and fast
moving. Now astronomers at the Jet Propulsion Laboratory have developed a technique called synthetic tracking
for dramatically speeding up asteroid discovery. Insteads of long
exposures in which near-Earth asteroids show up as faint streaks, the
new technique involves taking lots of short exposures and adding them
together in a special automated way. The trick is to shift each image so
that the pixels that record the asteroid are superimposed on top of
each other. The result is an image in which the asteroid is sharp point
of light against a background of star streaks. They say synthetic tracking has the capability to spot 80 new near Earth asteroids each night using a standard 5 metre telescope. That'll be handy for spotting rocks heading our way before they get too close and for identifying targets for NASA's future asteroid missions.
