It's a big sky out there. How are we going to find asteroids, especially those that might be threatening Earth?
While there are many dedicated asteroid searches out there - LINEAR, NEOWISE, Pan-STARRS, NEAT, Spacewatch Project, Catalina Sky Survey and more - there are three main limitations to looking for asteroids. The first is time, which is limited on telescopes that are popular. The second is resolution; asteroids are small and they are hard to see. And finally, there's trying to predict in which direction an asteroid can go.
Most near-Earth asteroids originate in the main belt of asteroids that is between Mars and Jupiter. Relative to the background stars, this means these little objects are moving fast.
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It's been a challenge for anything but a supercomputer to calculate all the possible trajectories from a few limited images, but one group says it may have cracked the problem at last with a high-powered desktop, simply because the tech has improved.
In a paper published on Arxiv and accepted in the Astrophysical Journal, three astronomers describe a technique where they take a bunch of short exposures of the sky. Then they digitally "shift" them in such a way that the images are combined, making the stars streaks and the asteroids a single point.
They claim this could find asteroids that are 10 times fainter than those found in conventional sources.
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The astronomers did a test survey in April 2013 using two nights (or data sets) of 126 and 130 images, and were able to process the data in 50 days using a desktop computer. The telescope was small - it was the WIYN 0.9m Observatory on Arizona's Kitt Peak - but the astronomers are hoping to use a four-meter telescope in Chile for the next stage, if they get the approval.
"It does take longer with a smaller telescope," lead author Aren Heinze, a post-doctoral researcher at the University of Hawaii, told Discovery News. "With a larger telescope, you can do a shorter exposure on each part of the sky and can cover the same part of the sky with more sensitivity in a small amount of time."
The astronomers say their idea could overcome a key limitation of conventional asteroid searches: as exposure times increase in an effort to find faint asteroids, the rocks' motion and faint appearance can make them blur into the background. However, the research is at an early stage and it will take some time to figure out how effective the new technique is versus the old one.