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KBO encounters
elakdawalla
post May 8 2011, 04:18 AM
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It's in beta, still several weeks from launch.


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NGC3314
post May 9 2011, 12:18 PM
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What John said - just found out that some of the people behind Galaxy Zoo have teamed with the NH folks to not only look for potential target KBOs (TNOs, whatever name won't get me in trouble), but enlist citizen scientists in the search And if UMSF isn't full of them, I don't know what is . (OK, Galaxy Zoo itself, but that's a different audience...)

At least one additional Zoo of great interest in UMSF is also in the works.
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hendric
post May 16 2011, 04:46 PM
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Just got this in the Zooniverse newsletter. I think it should be safe to post here!

New Beta Test for IceHunters

Last week we tested a new Zooniverse project "Ice Hunters" with
Galaxy Zoo: Supernovae and Galaxy Zoo users. Thanks to the help of
more than 3700 of you, we are now ready to expand our beta test to the
full Zooniverse.

To try out the site as a beta tester, go to:
http://demo.icehunters.org
The tutorial is here:
http://demo.icehunters.org/tutorial

The site will launch to the public in late May or early June, so
please keep this address to yourself for now. IceHunters uses data
around the world to look for Kuiper Belt Objects (KBOs), Variable
Stars, and Asteroids. The ultimate goal is to find the Kuiper Belt
Object (or Objects) that the New Horizons spacecraft will be
redirected to after in flies past Pluto in 2015. The data to find that
object is being taken right now. While we wait for it, we have loaded
in testing data from 2004 and 2005; images filed with unknown KBOs,
variable stars, and asteroids that appear as blobs and streaks in the
residuals of the subtracted images. Your name will be associated with
your every discovery, and catalogues will be published next winter.
Help us find new icy bodies today: http://demo.icehunters.org


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john_s
post May 16 2011, 05:20 PM
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Here's an update on how the KBO search is going so far.

This year, after several preliminary searches, we are finally kicking off the full-up search campaign. Our searches are possible only near new moon, and so we have obtained a bunch of telescope time once a month, starting with the late April new moon, and continuing in late May (when, by the luck of the draw of the telescope time allocation committees, we have the most time), late June, and late July. Time is divided between the Magellan telescopes in Chile, the Subaru telescope on Mauna Kea, Hawaii, and the Canada-France-Hawaii telescope also on Mauna Kea.

The first run, in late April and early May, on Magellan, went spectacularly well. We had superb weather and seeing (one night's report described "seeing deteriorating to 0.6 arcsec"- if you're an observer you'll know that's an unusual statement), and the data quality looks excellent. We're now in the process of reducing the data- the key step will be the matching and subtraction of pairs of observations taken hours or days apart, so we can remove the gazillion background Milky Way stars and leave behind the moving objects, which will include our potential KBO targets.

In a few weeks we'll be posting subtracted images on a site being developed by our partners at the Galaxy Zoo, where you'll be able help us to search for the moving objects. The late-May data may be the first posted- the late-April run is lower priority because the KBOs are harder to distinguish from asteroids by their motion in April. In the meantime, there's a beta version of the site already available, using data from an earlier (2004) search- I'll post more on that later today, when the site has had a couple more improvements.

John
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dilo
post May 16 2011, 09:39 PM
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Finally we can help you, I am so excited!
Just found a dozen objects in first 5 demo images; software is quite simple/straightforward, perhaps image quality section can be improved with more specific comments.
Thanks for this great opportunity!


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john_s
post May 16 2011, 09:56 PM
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As hendric and others have noted, the beta version of our KBO search site, Ice Hunters, is now online at demo.icehunters.org. We're not making a big public announcement till we launch the site with the 2011 data in a month or so, but in the meantime we'd love to have people sign up and start looking for objects the 2004 data currrently posted. This beta version will help us get the bugs out of the pipeline so everything is ready for the new data, but the 2004 data in the beta version are intrinsically scientifically useful too. Those data also covered the New Horizons search area, and may well include KBOs that New Horizons can access. Ideally, we'll find KBOs in our 2011 campaign that we can then trace back to detections in these 2004 data- in that case we'll be able to determine accurate orbits for those objects much more quickly, to see whether the spacecraft can reach them.

Thanks in advance for your help!
John
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stevesliva
post May 16 2011, 11:34 PM
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QUOTE (dilo @ May 16 2011, 05:39 PM) *
Just found a dozen objects in first 5 demo images; software is quite simple/straightforward, perhaps image quality section can be improved with more specific comments.

They are inserting fake ones to test you. Want to be rated well? Find the ones near the edges.

I'm not sure the fake ones are paired with a black blob... I get excited when I see those... more likely to be real.

I've also been wondering what binary and ternary KBOs would look like... same frame? Seems like that occurs a fair amount.
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john_s
post May 16 2011, 11:50 PM
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Actually there are no fake objects in the 2004 data on the beta site, so positive/negative pairs are likely to be a real slow-moving objects. However we probably will add artificial objects (with realistic motions, so they can also produce positive/negative pairs) in the 2011 images when they are posted- it's important to add artificial objects to the data to test what fraction of objects of a given brightness we can actually find.

Single objects, without a negative partner, may be moving objects in which the subtracted frame is taken a long time after the original frame, or they may be variable stars which have changed brightness between the times of the two images.

Oh, and most binary KBOs are very close to each other in the sky- often you need Hubble to separate them- so might or might not be resolved in our images.

John
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stevesliva
post May 17 2011, 12:03 AM
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Thanks john... I saw an old powerpoint of yours which mooted the fake KBOs, and was finding so many white blobs I figured you must be doing it already!

Also interesting regarding binaries. Makes me wonder whether the multiple "KBO" frames are just ones where the algorithm turned certain stars into white fuzzy blobs.
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hendric
post May 17 2011, 06:01 AM
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John,
Thanks for the update! I was curious, are you using a 16 or 32 bit FITS workflow? It seems like some of the images are suffering from a weird clipping like the subtraction was done on signed data but the conversion to an image format was done on unsigned data. Maybe you could provide a couple of sample images and we could hold a contest for the best subtraction algorithm. smile.gif


You said binary KBOs are likely to still be point sources on these images, what about binary asteroids/centaurs?

Also, is there a fixed image scale for these pictures, or do they vary?


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"The engineers, as usual, made a tremendous fuss. Again as usual, they did the job in half the time they had dismissed as being absolutely impossible." --Rescue Party, Arthur C Clarke
Mother Nature is the final inspector of all quality.
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MahFL
post May 17 2011, 12:50 PM
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Oh dear I can't use IE7, which is on my work PC, bummer.
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john_s
post May 17 2011, 02:44 PM
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QUOTE (hendric @ May 17 2011, 12:01 AM) *
John,
Thanks for the update! I was curious, are you using a 16 or 32 bit FITS workflow? It seems like some of the images are suffering from a weird clipping like the subtraction was done on signed data but the conversion to an image format was done on unsigned data. Maybe you could provide a couple of sample images and we could hold a contest for the best subtraction algorithm. smile.gif

I can pass on this question to Marc Buie, who is doing the subtraction algorithms, but I'd be very surprised if there were artifacts related to bit clipping. The subtraction of different point-spread functions, even after convolution to try to match them, can produce some pretty strange artifacts though. Maybe you could PM an example to me...

As to subtraction algorithms, part of the trick is to have something that works automatically on hundreds of different image pairs- we don't have the resources to manually fine-tune every example. However some preliminary tests on our 2011 data suggest that we'll be able to do better subtractions than we've achieved on the 2004 data- we'll see when we turn the crank on the full data set.

QUOTE (hendric @ May 17 2011, 12:01 AM) *
You said binary KBOs are likely to still be point sources on these images, what about binary asteroids/centaurs?

Probably the same- again most binary asteroids have been discovered using adaptive optics or Hubble.

QUOTE (hendric @ May 17 2011, 12:01 AM) *
Also, is there a fixed image scale for these pictures, or do they vary?

All are the same scale, 0.2"/pixel in the case of SuprimeCam on Subaru, which produced all the beta images.

John

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hendric
post May 17 2011, 03:10 PM
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Thanks for the reply John. I figured after I sent my message that there must be a limitation on the amount of CPU processing you want to do with each image, so that you can complete the whole queue in a reasonable amount of time. I'll try to PM you some examples.


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"The engineers, as usual, made a tremendous fuss. Again as usual, they did the job in half the time they had dismissed as being absolutely impossible." --Rescue Party, Arthur C Clarke
Mother Nature is the final inspector of all quality.
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tfisher
post May 18 2011, 01:56 AM
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I can discern 8 parallel, nearly horizontal, rows of artifacts per image tile. Once you start looking for it you can see this on every image. Any idea what causes that? Maybe some side effect from the subtraction algorithm?

[Edit:] Well, I had about 30 images in a row with those parallel rows of artifacts; now I'm not seeing them any more.
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nprev
post May 18 2011, 02:40 AM
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John, though this is not a technical commentary, have to say that the user interface is quite effective, and even a rank amateur like me picked up on the methodology rather quickly. Suggestion: Might not be a bad idea to explain in the tutorials why stars are black in the middle (because they are very distant point-sources of light & therefore wash out the exposure in a smaller area than would be expected for a KBO because the latter are much closer; helps people understand why blobs=good.)

Okay, back to searching for one of the next targets! smile.gif


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