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"Synthetic Tracking" Makes It Possible to Find Millions of Near Earth Asteroids
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."
How many hedgehogs to an apartment block?
Or does the submitter not see the apparent logical flaw in the way the described this process. If you're going to line up each image so that the asteroid is a single sharp pixel and the stars are streaks, doesn't that suggest that you already know which pixel is the asteroid? In which case you don't really need to search for that particular asteroid, no?
At a minimum the submitter or the editors need to think whether their description of the procedure is good.
Wha...? Asteroids the size of apartment blocks?
Can we please have this measurement in a standardized unit, like Volkswagen beetles?
Man. I thought Slashdot was going downhill back when it was mostly a CueCat fansite, but this really takes the cake.
Seems like that would only work if you knew the speed and direction that the asteroid was moving in. and, of course, if you knew that then that might not be the one that you needed to find.
I'm an American. I love this country and the freedoms that we used to have.
by any chance, are any of them on course to hit the Capitol, or better yet, Wall Street?
It seems like it would be much simpler to just use optical flow to find moving objects.
I am becoming gerund, destroyer of verbs.
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Fuck systemd. Fuck Redhat. Fuck Soylent, too. Wait, scratch the last one.
"Medium.com" is one of those aggregator sites. Don't link to them. Link to the actual paper. 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.
Anyone else thought of that while reading the summary?
It always amazes me that the people that complain all the time about Slashdot with dupes, bad articles, etc. come back every day just so they can tell everyone how bad it is. It's as though they sit and wait for it just so they can make long winded comments on how bad Slashdot is. It is getting really old.
--- If the bible proves the existence of God, then Superman comics prove the existence of Superman.
Why would you brute-force the pixel shifts to get the asteroid in a single spot, when the fixed background stars are already a stable reference for co-aligning the images? It seems the simpler way (even with the short exposures) would be to cross-correlate and co-align to the background stars, then look for the "dotted" path of the moving asteroid. And isn't it already done this way?
I don't get what's so revolutionary about this. As an astrophotographer, I know how to take lots of short exposures and stack them to make one frame that easily shows moving objects, comets, asteroids, satellites, etc. There's even a piece of freeware that has "comet mode" where it will take your stack of exposures and find the object that's not moving the same way with respect to the background stars. Same thing...
Yes, like the kind you buy on amazon.com, right?
That this is cool. Anything that will help humans identify the source of their ultimate demise is a good thing.
So now we can find a lot more very dangerous space rocks. That's excellent. However, we can't really do much about them unless we can mass-produce space shuttles, clones of Bruce Willis and Ben Affleck, and crappy Aerosmith songs. But if survival means a world with multiple Ben Afflecks and getting ear-spammed by more sappy Aerosmith power ballads whenever I turn on a radio, we'd be better off with the asteroid impacts.
I'm amazed they they weren't doing something like this already. I think its a pretty standard cross correlation filtering method. They even say they're brute forcing it with a GPU, which surprised me. Am I missing something or could this be sped up quite a bit with FFT?
How does this compare to using regular edge detection to find faint streaks in a time lapse image? How about after detecting bright spots and deleting them followed by edge detection?
I say again...WHAT?
This is an old technique, and I would have thought they would have been doing this for YEARS!
Those of use in the IT field, know how to come up with some stuff like that, all the time, because we think in a very logical way. For the rest of you scientist; if you are working on any kind of complex problem, or you are simply trying to find a faster or more efficient way, then you need to at least talk to some people in the IT field and get some help. The scientific advancements could be leaping ahead.
Seems as though using an initial long exposure, and finding the streaks that may be NEAs, could inform the search process for the velocities required to align short exposures. It's not as though the NEA trajectory should change after the long exposure was taken.
The more sensitive camera and the algorithm to empirically find the correct direction and speed of movement of a not-known asteroid are new.
The method of overlaying multiple short images so that the asteroid is a pinpoint additive composite of multiple images and the stars become trails is not new.
The latter technique is called "stacking" (a word existing for quite a long time and meaning the same as their "synthetic tracking"). It is regularly done to image and get astrometry on faint objects, when speed and direction of movement are already known (e.g. in follow-up observations on a Near earth Asteroid that already has some observations over the previous hours/days and hence a preliminary orbit). That part is really not new, and there is no need to invent new terminology ("synthetic tracking") for it.
Frankly, it is weird that the authors nowhere mention "stacking" as an existing technique that is often used in imaging faint asteroids. It suggests they did not investigate whether their "new" technique is really that new. Yes, they innovate on it, but they did not invent a completely novel technique.
Ceterum censeo Carthaginem delendam esse
Credit where credit is due.
The most common open source software used for this is called REGISTAX, and it was developed by a Dutch amateur astronomer in 2001. Google it. Amateur telescopes are often small, so they have much fainter images than the professionals, and they developed their own method of making them brighter.
It sounds as if JPL have just heard about this, and decided to use the same technique. Sensible, but hardly ground-breaking.
This is a simple and nifty idea and it works.
Good now we can find those small ez to mine rocks nearbye. Or use those rocks for other purposes... build your habitat directly in one.
Credit where credit is due.
It's called inverse synthetic aperture imaging, and people have been doing it for decades prior to 2001. The difference here is they're doing a brute-force search to discover the motion vector, rather than knowing what it is from the beginning, but then even that's not a new concept. It's merely a concept that is only recently possible due to increases in computational power.
since I lapped my 12" mirror for my telescope.
"They say synthetic tracking has the capability to spot 80 new near Earth asteroids each night using a standard 5 metre telescope."
standard.
5 metre.
what a brave new world...