"Synthetic Tracking" Makes It Possible to Find Millions of Near Earth Asteroids 101
KentuckyFC writes "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."
Quit spamming for "medium.com" (Score:5, Informative)
"Medium.com" is one of those aggregator sites. Don't link to them. Link to the actual paper [arxiv.org]. Thank you.
They had to use the Palomar 200 inch telescope to make this work. There aren't many big telescopes in the world, and they're booked months in advance. They got a few hours of observing for one night, and good results. But they'd need a lot more observing time on big scopes to do their survey.
Re:Is it just me? (Score:5, Informative)
From TFA:
The difficult part of this is knowing which way to shift each image. Shao and co have solved this by brute force: they take consecutive images and examine all possible shifts to see which resolves the fast moving asteroid.
That's a lot of computation (they try 1,000 different velocity vectors), but that's what computers are really, really good at.
Re:Is it just me? (Score:2, Informative)
Article doesn't have a good description.
Before the detection of the NEA, its velocity vector is unknown. However, we find this vector by conducting a search in velocity space. To do this we have developed an algorithm that simultaneously processes the synthetic tracking data at different velocities. The velocities searched initially have (x,y) components that are multiples of 1 pix/frame in each direction. This is a computationally intensive task: for example, the shift and add process for 120 images for 1,000 different velocity vectors requires over 1011 arithmetic operations. However, with current off-the-shelf graphics processing units (GPU) with up to 2,500 processors and teraFLOPS peak speeds, we were able to analyze 30 sec of data in less than 10 sec. Once the NEA is detected in this initial search, an estimate of velocity becomes possible. Using this velocity we refine the astrometry relative to a reference star in the field and determine the velocity to a much higher precision. Elsewhere we plan to describe the details of the synthetic tracking algorithm and report its performance, including its false alarm rate.