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Posted by: xtruel Aug 2 2008, 12:53 PM

Hi,

I’m regular follower of NH and I’m also interested in the 2nd leg of the mission, i.e the 2016+ KBOs encounters. Does anyone know when operations about this leg (starting with searching objects of interest with HST or some other earth-based means, I suppose) are expected to begin ?

Posted by: nprev Aug 2 2008, 01:06 PM

Hiya, X. If I remember correctly, the KBO search isn't really going to kick into gear until 2010 because Pluto (and the cone of possible follow-on destinations) is in Sagittarius from our viewpoint right now, which is the galactic core region...too much background optical 'noise' from all those stars to distinguish targets. Once it moves clear, the hunt will begin. Don't think that HST will participate (might be wrong), but several large ground-based observatories will certainly be involved.

Posted by: Alan Stern Aug 2 2008, 01:26 PM

KBO searches will be conducted in 2011-2012, when the relevant KB fields are out of Sag as Nprev described. Target characterization and prioritization will occur in 2013-2014. Target selection will be in 2015.

HST's FOVs are too small to use profitably for searches. We will use wide field imagers on groundbased, big guns like Keck, Subaru, etc.

-Alan

Posted by: Paolo Aug 2 2008, 03:32 PM

Remember when they called asteroids "the vermin of the sky"?

Posted by: nprev Aug 2 2008, 04:48 PM

...our definition of celestial vermin seems to be shifting, doesn't it? Bloody core stars...

Posted by: xtruel Aug 3 2008, 07:36 AM

Thanks for these quick replies

Given the tiny angular size of expected objects, It seems likely that science data about them to be collected by earth-based means, in order to perform target characterization & selection, will be limited, and may be already known in its headlines. Orbit characterization, absolute magnitude, color may be among these. Are there others ? In particular, will it be possible by earth-based means (or HST) to detect & characterize a binary object and is there a reasonable probability to find one ?


I also wonder if there is some hope that NH after its KBO mission may be aimed at an « inner Oort-Cloud object » (Sedna-like) as these objects raise currently deepest mysteries about how they formed, how they have been put in there, etc... . This would need some fuel left, and also long term NH survey and survival. Clearly this is not currently planned, but this may be the first realistic opportunity to have a close look at Oort cloud...

Posted by: Greg Hullender Aug 3 2008, 04:01 PM

Trouble is, it'll take NH almost 10 years to go 40 AU, and the inner edge of the Oort Cloud is estimated to be about 2000 AU out. A 500-year extended mission is probably asking for too much. :-)

http://en.wikipedia.org/wiki/Oort_cloud

Since Sedna's the only thing like Sedna, I think it'll be hard to guess that we'll find another before 2015 AND that it'll be reachable by NH.

That does raise an interesting question, though. From the NH mission page: http://pluto.jhuapl.edu/mission/mission_timeline.php it's not clear how much time NH could have to reach a KBO. A ten-year extended mission could roughly reach the perihelion distance of Sedna from the Sun, but is anyone contemplating an XM that long? How long can we reasonably expect NH to work?

--Greg

Posted by: Alan Stern Aug 3 2008, 04:35 PM

We're hoping for a 4-6 year extended mission (XM), taking us to perhaps 50 AU. The heart of the KBO population is at 42-43 AU, and after that it thins out. By 55 AU we're out of the Classical Belt and into the much more dilute Scattered Belt.

We expect to fly by 1 or perhaps 2 KBOs each ~40 km in diameter in the XM. Larger ones are too few and far between to reach with our fuel supply unless we are very lucky, but the statistics are against us.

My job as PI is not to fly as far as we can but to maximize the value of the KB exploration we can achieve. This translates to accomplishing one post-Pluto KBO flyby within 2 or 3 years if we possibly can (to ensure against later failures) and to pick up a second KBO for comparative purposes if possible thereafter.

-Alan

Posted by: surreyguy Aug 3 2008, 05:06 PM

Is larger necessarily better? Planets (in the hydrostatic sense) are always interesting, of course, but geology has a way of erasing information. A 40km KB equivalent of a chondritic meteorite would be fascinating, if frustrating given only a few hours of remote sensing are possible.

I love the audacity of it, though, to go off to study something without having discovered it yet.

Posted by: Alan Stern Aug 3 2008, 05:09 PM

We'll see it for days on the way in, possibly longer. And FYI, 40 km is Eros size.

Alan

Posted by: nprev Aug 3 2008, 05:49 PM

Just out of curiosity, Alan, is encounter relative velocity for KBOs basically a constant? These things have very small heliocentric relative speeds if they are not in highly elliptical orbits, so NH's outbound velocity is presumably a criterion for deciding whether or not to select an object based on encounter timing & size (i.e., you'll get a lot more hang-time for a 500km diameter KBO then a 40km).

Posted by: Alan Stern Aug 4 2008, 10:59 AM

Nprev-- All KBO encounters are at approx the same relative speed, ~12-15 km/sec, independent of KBO size. Don't know whatyou mean about hang time...

Alan

Posted by: nprev Aug 4 2008, 11:10 AM

Oh, sorry. What I meant is that presumably more data (esp. imagery) could be acquired when encountering a larger object then a smaller one; for example, a larger one would have resolvable features further out & also post fly-by.

Posted by: Alan Stern Aug 4 2008, 01:24 PM

True, but the stats just make it unlikely--too few and far between. Best we can realistically hope for is 70 km diameter if I choose to go to just one instead of 2 KBOs. That's what the Monte Carlo models for detection statistics within our accessible region after Pluto tell us. Nontheless, the KBOs we will get will be 10^5 times the masses of km-scale comets and will teach us an enormous amount about KBO evolution, chemistry, geology, etc.

-Alan

Posted by: surreyguy Aug 4 2008, 06:42 PM

Thanks for the correction, Alan. And yes, I should have said 'parent body of' somewhere in there.

Here's hoping that you get enough options to do some trading (red? grey? hot? cold? scattered?).

Posted by: tasp Aug 4 2008, 07:07 PM

Not sure I am thinking this through correctly, but if the number of smaller objects increases fast enough, do we get to the statistical likelihood of a useful non targeted encounter (light curve, size determination, confirm no satellite/binariness) of any objects in the 5 km size?

Maybe a better question is, are there enough 5 km 'rocks' that the possibility of useful science (with no additional fuel used) in a 6 year XM exists ?

Seems like the NH spacecraft 'useful encounter sphere' is rather large, and as it traverses the belt would it intersect anything tiny but interesting?

Posted by: Alan Stern Aug 4 2008, 07:20 PM

Could be, but no one knows (i) how many objects there are that small-- or how to see them from Earth, so it's impossible to estimate well and even harder to find one and aim for it. NH can't do the job-- the imaging FOVs are too small and the bit rates too low. Believe me, we've thought of all this years ago.

Alan

Posted by: tasp Aug 4 2008, 07:47 PM

Thanx.

I guess we get to work out the statistics for the smaller bodies the old fashioned way.

Counting craters on the bigger ones we can see.

Posted by: nprev Aug 4 2008, 07:49 PM

Alan, what is the search magnitude limit for the hunt? If you're talking 70km objects or smaller at that distance, I'm gonna guess mag 24 or lower...amazing!!!

Posted by: Alan Stern Aug 4 2008, 09:13 PM

28th magnitude.

Posted by: nprev Aug 4 2008, 09:18 PM

THAT is a definite "wow!!!!" Absolutely amazing; didn't know that modern CCDs would go that low, even with such enormous light buckets!

Man...I can really understand the need for the field to be clear of Sag now much better. I thought that maybe you guys could still do something now, but it'd have to be a major object to stand out from that mess.

Posted by: xtruel Aug 5 2008, 04:10 PM

My former question may be reformulated as follows : After completion of extended mission at KB, NH’s mission officially ends. Spacecraft will be at something like 50 AU. Maybe some fuel will still be left. From this point, will be something else worth trying ? Previous outbound spacecraft (Pioneers, Voyagers) have all been maintained until they really die, we may expect the same for NH. I had in mind a possibility of targeting some object at scattered belt (however small it might be) which may be a SDO or an object currently cruising near perihelion whose orbit type is similar to Sedna (70-1000 AU or the like), thus qualifying as “inner Oort cloud object” as I’ve read somewhere. But according to Alan’s info I now believe this as unrealistic as SDOs are simply too far apart. So next possible milestone would be escape from heliosphere ?

This is very long term thinking, I agree…

Posted by: vjkane Aug 5 2008, 04:38 PM

The Voyagers and Pioneers had capable particles and fields instruments. Anyone know if NH's SWAP and PEPSSI instruments would be good for exploration of the heliopause? Also, NH left Earth with a smaller than expected payload of plutonium. How far could it go and still (1) operate the instruments and (2) call home?

Posted by: Alan Stern Aug 5 2008, 05:39 PM

We could probably run the s/c and 1 instrument to the mid-2020s to explore the heliosphere 50-70 AU, but that's not the mission-- the mission is to maximize the KB science, and that means spending all the fuel to do that.

Alan

Posted by: IM4 Aug 17 2008, 10:41 AM

We have no candidates for close KBO enccounters, but what about distant ones? My program predicts that en route to Pluto and beyond NH will pass by several Centaurs within 1-3 AU :

That's too far for detailed imaging but I believe useful photometric science (phase curve or something) can be obtained with LORRI or other instruments. Of course that make sense only if LORRI is sensitive enough, since apparent magnitude of these objects will be ~ 16-17m.
Are there any plans for such kind of science?

Posted by: Alan Stern Aug 17 2008, 11:49 AM

Yes.

Posted by: IM4 Aug 17 2008, 03:18 PM

Interesting.
Any details?

Posted by: Explorer1 Apr 14 2010, 04:42 AM

Looks like the 'flyby' of Crantor came and went. Did anything significant happened?
Probably not, since no mention on the NH twitter feed, I checked.

Posted by: Hungry4info Apr 14 2010, 01:56 PM

Couldn't blame them if they didn't do anything. Not a whole lot you could do at 2.76 AU.

Posted by: Vultur Apr 15 2010, 09:15 AM

The first post in this thread says the search would start in 2010 - has it started yet, or will it be later this year?

Posted by: nprev Apr 15 2010, 09:32 AM

Actually, Alan said in http://www.unmannedspaceflight.com/index.php?s=&showtopic=5368&view=findpost&p=122127 that the search won't start till next year.

Posted by: Alan Stern Apr 15 2010, 12:18 PM

Our best imager, LORRI, can resolve the size of an object from roughly 10^5 object diameters away. So for a 100 km object, for example, we have to be w/i 10^7 km just to resolved it; if you want crude shape information, cut that to 10^6 diameters, and if you want "geology," well, better come to approx 30,000 diameters or better. The point here is Crantor and other distant flybys don't yield much of use, so we have not expended effort on them.

As to our KBO search, John Spencer is leading the organizational effort to recruit search teams; Andrew Steffl is helping John. Our plan is to conduct the search in 2011 and 2012, though Scott Shepard at least has already begun.

-Alan

Posted by: Greg Hullender Apr 15 2010, 04:58 PM

Yeah, I think the last few times we've asked this question (maybe we need an FAQ section for each long-term mission) the answer was "not until we're past the orbit of Uranus."

--Greg

Posted by: illexsquid Apr 27 2010, 06:11 PM

Alan, thanks for the info, but I'm a little confused... I assume that for crude shape information, you mean cut the maximum distance to 10⁶ kilometers, since 10⁶ diameters would be 10⁸ kilometers. But which do you mean for the "geology" figure? 30,000 diameters would be 3 million kilometers for our theoretical 100 km object, which is tough enough, but 30,000 kilometers is more or less a bullseye: better targeting than even Apophis will manage . It seems to me you could get at least some worthwhile surface-feature resolution at a greater distance than that. The famous LORRI images of Tvashtar's plume resolved fine details at 2.5 million km. On the other hand, I know that spacecraft (and ground) resources are limited, and you have to be sure you're getting enough meaningful data for any expenditure. Could you give any hints as to when you think it might be worthwhile to observe during one of these flybys?

Posted by: Gsnorgathon Apr 28 2010, 05:55 PM

The Tvashtar plume images were taken a lot closer to the sun than any KBO images will be. I imagine blurring due to longer exposure times would reduce resolution at comparable distances.

Posted by: john_s Apr 28 2010, 07:36 PM

I'll chip in here. Alan was talking about science at Centaurs that we might fly past on our way to Pluto- none of those will get close enough to be resolved. For the KBO target(s) beyond Pluto, we will deliberately target to get within a few tens of thousands of kilometers or closer- from 20,000 km, for instance, we would get 500 pixels across a 50 km KBO- sufficient to do some serious geology. LORRI can get well-exposed, unsmeared, images at Pluto's distance from the sun (it was designed to do that, of course), and while illumination conditions will be more challenging further out in the Kuiper Belt, there's enough performance margin that we expect to be able to do the same there.

At Crantor's distance, a LORRI pixel is 2000 km across, much bigger than Crantor itself. So there's no hope of getting any shape information.

And to make sure no-one is still confused on this point, we will not be searching for KBOs with NH itself- huge ground-based telescopes with wide-field imagers can do that much better, even though they're stuck at 1 AU.

John

Posted by: john_s Feb 22 2011, 10:55 PM

Talking of KBOs, here's a heads-up that YOU can probably help us to find Kuiper Belt objects for New Horizons to fly by after Pluto, starting in a month or two. We're working with the http://www.zooniverse.org/ folks to set up a "KBO Zoo" where you will be able to help us identify moving objects (i.e. potential KBOs) in the Milky Way star fields that we'll be imaging with the Subaru, Magellan, and Canada-France-Hawaii telescopes this summer. Details once the site is up and running.

John

Posted by: Astro0 Feb 22 2011, 11:01 PM

If we find it, can we name it?! I always thought that "Astro0's Orb" had a nice ring to it!

Posted by: stevesliva Feb 22 2011, 11:54 PM

Sweet!

Posted by: nprev Feb 23 2011, 01:10 AM

THAT is a rockin' piece of citizen science outreach, John! Very much looking forward to it!

Posted by: hendric Feb 23 2011, 02:54 PM

John,
That's great news, can't wait to participate in the search for targets!

Posted by: MahFL Apr 20 2011, 02:59 PM

http://pluto.jhuapl.edu/news_center/news/20110420.php

Posted by: john_s Apr 20 2011, 03:17 PM

Look for another release in a few weeks, describing how you can help us sift through all those images.

John

Posted by: dilo Apr 20 2011, 03:47 PM

Great, I cannot wait!!!

Posted by: tfisher May 8 2011, 03:12 AM

Any update on this?

Posted by: elakdawalla May 8 2011, 04:18 AM

It's in beta, still several weeks from launch.

Posted by: NGC3314 May 9 2011, 12:18 PM

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.

Posted by: hendric May 16 2011, 04:46 PM

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

Posted by: john_s May 16 2011, 05:20 PM

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

Posted by: dilo May 16 2011, 09:39 PM

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!

Posted by: john_s May 16 2011, 09:56 PM

As hendric and others have noted, the beta version of our KBO search site, Ice Hunters, is now online at http://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

Posted by: stevesliva May 16 2011, 11:34 PM

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.

Posted by: john_s May 16 2011, 11:50 PM

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

Posted by: stevesliva May 17 2011, 12:03 AM

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.

Posted by: hendric May 17 2011, 06:01 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.


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?

Posted by: MahFL May 17 2011, 12:50 PM

Oh dear I can't use IE7, which is on my work PC, bummer.

Posted by: john_s May 17 2011, 02:44 PM

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.


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


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

John

Posted by: hendric May 17 2011, 03:10 PM

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.

Posted by: tfisher May 18 2011, 01:56 AM

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.

Posted by: nprev May 18 2011, 02:40 AM

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!

Posted by: john_s May 18 2011, 03:59 AM

If you see them again, maybe make a screen grab and send me a copy by PM...

Thanks,
John

Posted by: john_s May 18 2011, 04:05 AM

Thanks for the suggestion- it would be nice to have a bit more technical explanation for those who are interested. However the presence of black blobs isn't due to stars being further away or being "smaller" sources (the KBOs themselves are point sources for all practical purposes, and are as small as the star images). Rather, it's because stars don't move, so each positive image of a star is combined with a negative image of the same star when the subtraction is done- imperfections in the subtraction leave some negative (black) pixels as a result. The KBOs have moved on by the time the negative image is taken, so there's no superimposed negative image- all you get is the unadulterated positive image. Hope that makes sense...

John

Posted by: nprev May 18 2011, 05:02 AM

Swing and a miss...but knew there had to be a reason for the pronounced dichotomy! Thanks, John. At the very least, a 'why not' rationale for the most easily misidentified objects should improve your SNR a bit.

Posted by: hendric May 18 2011, 04:30 PM

I figured the black star centers was because of a "perfect" subtraction, ie 255-255=0, and the outside stays white because the gaussian applied to the PSF isn't exact.

tfisher,
I also saw those same parallel lines. I think it's caused by a bad CCD in the array. It doesn't quite seem perfectly horizontal though, it seems like it slants down one direction.

I have seen some giant hot pixels, hence my previous "binary" questions. I was pretty excited about seeing two move in the same direction until I saw the same two objects in a couple of images. Is it sad that I can now recognize parts of the CCD based on the hot pixels? I'm not sure if I should mark the hot pixels as blobs, since they meet the criteria, but I think I can notice them now since the KBOs seem fuzzy-edged but the hot pixels are hard-edged.

Sample of the hot pixel images. (animated gif)

Also, seen something a few times that is either a rapidly changing dust/gas cloud, or shmutz on the CCD. Seen something similar in the same spot a few times, but only got one screen cap of it, so my money is schmutz.


Here's my best example of what looks like ringing.


And my favorite bunch of blobs so far.

Posted by: john_s May 18 2011, 05:22 PM

Nope, because zero is actually gray- we stretch the differenced images to show both positive and negative residuals, and so we can properly see the noise in the sky (which is scattered around zero, for a good sky subtraction). We certainly don't do byte arithmetic.



Well spotted- yes, those are CCD defects, and the hard edges are diagnostic (sometimes the edges also show "ringing" due to the convolution). If you are sure you're seeing a hard-edged defect, don't mark it, but if in doubt, certainly err on the side over-clicking rather than under-clicking.

John

Posted by: hendric May 18 2011, 07:12 PM

John,
Good to know, I wasn't implying you're doing byte math, just trying to give a simple example. I understand now about using -/+ math and stretching it to make gray the middle.

I think this is an example of the horizontal banding tfisher referred to. It's not perfectly horizontal, but displaces downwards a few pixels across the whole image.

Here's something interesting. Assuming these two asteroids are at the same distance (I'm using 2.5 AU, center of the belt ), they're only ~ 20,000 km apart.

Posted by: tfisher May 18 2011, 09:55 PM

Yes, that matches what I have been seeing.

Thinking a bit more, I bet it starts out completely horizontal as the image comes from the ccd. But to subtract two images, they first have to be reprojected to a common frame of reference, so it isn't quite horizontal anymore.

Posted by: tfisher May 19 2011, 01:46 AM

Poking around more at the horizontal artifacts... They occur even in the images on the http://demo.icehunters.org/tutorial page. Here's a quick experiment. I took the "Image 1: Original from 2004-Jun-09 at 11:40 UT" and subtracted this image from itself translated vertically by one pixel. Then I remapped colors so nearly equal values are white and all others are black. The result is attached, showing approximately horizontal lines where there are equal pixel values just above one another.

Interestingly, the "Image 2" has almost to-the-pixel identical lines. If this was coming from a ccd readout problem I would have guessed they wouldn't match up so well. So maybe it is a bug from the image reprojection step?

Posted by: john_s May 19 2011, 04:03 AM

Thanks for these examples, Richard and all!

Though of course if one's at 2.50 AU and the other's at 2.51 AU, they are 1,500,000 km apart... And they might be variable stars too- we're still getting a feel for all the stuff that's buried in these data.


John

Posted by: hendric May 19 2011, 05:53 PM

Oh sure, if they're not the same distance. I figure the odds are better that two streaks in the same direction with very similar lengths are co-orbital vs happenstance alignment.

Posted by: stevesliva May 21 2011, 01:36 AM

I thought this was a thing of beauty, as far as finding transients in dense starfields go.

Posted by: nprev May 21 2011, 03:54 AM

Okay, I'll play: I see two, possibly binary.

This particular processing method seems to make them stand out, if I was correct.

Posted by: tfisher May 21 2011, 01:48 PM

Are Kuiper belt objects distributed like a belt, or more like a shell?

When I find close asteroids (the ones with three closely spaced bright marks), they always seem to move approximately horizontally across the image. But when I find distant bright blobs with a corresponding dark blob, they seem just as likely to be separated in any direction.

Or is it just that there are so many other sources of variable brightness besides KBO's, that most of the time when there are a bright blob seeming paired with a dark one it is just a chance occurrence. Like two out-of-sync variable stars near each other from our viewpoint?

Posted by: john_s May 21 2011, 03:19 PM

Most KBOs are in a flat disk, like the asteroids (though there are dramatic exceptions), and here we're looking in the plane of the disk so most KBOs we find will be trundling along in the same direction at similar rates. That's good, because it means most are heading in the general direction of the New Horizons trajectory (though we expect only a few percent of the KBOs we find to be accessible to the spacecraft).

And yes, most point-like variable or moving objects in the frames are probably *not* KBOs - they're variable stars or sometimes even artifacts such as CCD defects, as discussed previously. That's why we need all this help in cataloging everything, so we can sort out the few objects that really are of interest to us. So thanks again!

John

Posted by: nprev May 21 2011, 10:36 PM

John, interim progress report. 238 objects identified in 801 images, which means I see a candidate on the average in 29% of the images...call it one of every three. How does this compare with the expected results? Might have been skewed in the first few dozen or so, but I think I got it down now.

Also, is anyone gonna follow up on asteroid finds? I assume so, since they're scored as well.

Want to say again how much I enjoy the user interface; it's well thought-out, VERY easy once you get used to the detection methodology, and downright addictive!

EDIT: Forgot to add a suggestion: a "back" button! A couple of times I spotted a candidate just after I clicked "done"; couldn't fix it!

Posted by: nprev May 23 2011, 11:57 PM

Possible bug report: I'm on the road now & just tried doing a few images from the hotel. Did about 10, and the stat counter is frozen at 1900 objects discovered (wrong), 814 images viewed (never changed.)

Posted by: Tman May 24 2011, 09:34 AM

Hi, that happens because of the last update on Sunday. You may have to go via a log-out and in, then it should run again.

Posted by: nprev May 24 2011, 02:07 PM

Sure enough; thanks, T! (Der...there's was even a warning about this had I scrolled down the screen a bit...)

Posted by: john_s Jun 21 2011, 01:55 PM

The http://www.icehunters.org/ project is now out of beta and is officially open for business!
Thanks to everyone who worked on the beta version- the feedback from that work has helped improve the site, and the work was directly useful too- the team is now sifting through all the objects identified by the beta testers.

The official site will continue the work rather than repeating what's already been done- we'll complete analysis of the data from the preliminary 2004 and 2005 searches, and then move on to the data from the 2011 search program currently under way.

http://www.pluto.jhuapl.edu/news_center/news/20110420.php is the official release, and thanks to Emily for a http://www.planetary.org/blog/article/00003073/ on her blog today.

Here's an update on the 2011 telescopic campaign. Following a spectacular run on the Magellan telescope in Chile in late April and early May, we had poorer luck with the weather during the late May/early June dark time, but still got useful data at both Magellan and at the Subaru telescope on Mauna Kea in Hawaii. We're now preparing for the late June/early July run, which will again use both Magellan and Subaru, plus the Canada/France/Hawaii telescope also on Mauna Kea. This time I'm looking forward to going to the telescope myself- I'll be at Subaru on the nights of July 1st and 2nd.

John

Posted by: Alan Stern Jun 22 2011, 12:04 AM

And thanks to John Spencer for expertly spearheading this key corner of the NH project--observations, data pipelines, IceHunters, all of it! Now all you UMSFers: Go get in the game-- we need KBO targets-- an I'd say few are better suited to make the discoveries than the UMSF gurus!

Posted by: nprev Jun 22 2011, 01:30 AM

Great Godfrey!!! A PI has called for aid!!!

<Superman voice> THIS looks like a job...for UMSF!!! Go forth & find a target for New Horizons, friends!!! </Super! >

Posted by: NickF Jun 22 2011, 05:24 PM

I find it helps to move the mouse pointer away from the 'Done Marking' button after I click it. Too easy to click through otherwise!

Posted by: Sunspot Jun 22 2011, 10:16 PM

It's very addictive

Posted by: nprev Jun 22 2011, 10:53 PM

Yeah, ain't it? I'm over something like 2100 images now.

Posted by: nprev Jun 25 2011, 09:50 PM

Okay, now @ 2257 images with a detection rate of 18% (incl. asteroids). How does this compare with everyone else's stats so far?

Posted by: Stu Jun 25 2011, 09:54 PM

18%? And you haven't shown us a *single* image yet. That's disgraceful! Don't you know how important sharing pictures is?

Posted by: nprev Jun 25 2011, 10:30 PM

<abashed look> I didn't think anyone was gonna want to see images of circled little blobs...I stand corrected! Okay, will post anything I see that seems cool from now on.

One thing I've noticed is that there do seem to be multiple objects sometimes. Probably this is a misperception on my part due to the processing technique combined with the 286 processor in my head, but I have to wonder if sometimes we're seeing not exactly binary but somehow loosely associated KBOs. Of course, given the distances involved, true binaries wouldn't be distinguishable in these images & any two given objects are likely millions of km apart.

EDIT: Okay, Stu, just did another small batch, and these are esp. for you!

First, a small asteroid (not marked, upper right), and a little possible KBO (marked.)

Posted by: stevesliva Jun 26 2011, 04:24 AM

My finding rate is much higher, but the number of images I've seen is much lower... wouldn't be surprised if folks like nprev are prioritizing images for others to see.

Finding some interesting yin-yang perhaps slowly moving objects in some of the newer images:

Posted by: elakdawalla Jun 26 2011, 04:39 AM

Ha! I just independently saw that exact same one and called it the exact same thing in a comment at icehunters.org a few minutes ago! And also noticed your username among the other people who'd notated that one! Clearly great (UMSF) minds think alike

Posted by: nprev Jun 26 2011, 06:09 AM

Now HERE'S a beauty: one asteroid plus one possible KBO:

Posted by: centsworth_II Jun 26 2011, 09:45 AM

Really! I have to admit being a little confused by the messier images but that one is "textbook". Nice outreach to those of us too busy or lazy to investigate the search site ourselves. I'm sure it will spur some more interest and participation.

Posted by: NickF Jun 26 2011, 03:41 PM

If we're comparing rates, I've highlighted 201 potentially interesting objects in 891 images (22.6%, username 'nef').

Here's one of my favourites so far

Posted by: nprev Jun 26 2011, 07:06 PM

Eek! We're heading into an asteroid field (upper left)!!!

Posted by: nprev Jun 26 2011, 07:08 PM

...and dig THIS behemoth. Perhaps a TNO rather than a KBO? Dunno.

Posted by: nprev Jun 26 2011, 07:37 PM

Last one of the day: A two-fer?

EDIT: Please disregard the third circle around nothing; just a stray click, fixed it before submitting the image to Icehunters.
EDIT2: Damn it, looks like I might've missed a small asteroid just below the rightmost KBO candidate!

Posted by: nprev Jun 26 2011, 09:24 PM

Sorry, but I HAD to post this. Satellite trail? NEO?

Posted by: Marz Jun 27 2011, 12:03 AM

Great stuff!!! I've gone through 114 images with 96 objects. Perhaps I'm being too overzealous with some of the blobs I've marked, since the margins seem like they were edited during the subtraction process. However, their center is white, so I figure it's better to flag it as something to investigate.

I hope we hit the jackpot! Seems like a great way to filter data for a sky survey -- farm it out to the eager masses!

Posted by: nprev Jun 27 2011, 12:13 AM

Thanks for that comment, Marz. Been wondering if I've been too conservative, actually, but my viewpoint has been that I want to get stuff that's pretty much unmistakable...no idea whether that's the "right" approach, of course. I think that statistically this should balance out well; obviously, one of the key discriminators must be whether multiple observers tag the same pics & objects, and that seems like the best possible filter for the inherent subjectivity of these observations.

Gotta say, though, that this has been FUN!!! If anyone's been on the fence about jumping in, let me tell you there's no reason at all to hesitate; beats the hell out of surfing tired news or whatever when you're on the Web & not doing anything in particular...

Posted by: NickF Jun 27 2011, 02:46 AM

Indeed. How often in your life are you given the opportunity to spot something floating in the Kuiper Belt?

Posted by: nprev Jun 27 2011, 03:31 AM

I'm thinkin' maybe just this one time, Nick, 'cause I ain't gonna live forever...let's take full advantage of it!!!

Posted by: ElkGroveDan Jun 27 2011, 04:25 AM

OK I'm addicted now.

Posted by: centsworth_II Jun 27 2011, 08:35 AM

Just finished my first 200 (as "cents"). Almost relaxing. WAY easier than the Stardust particle search which was too taxing on me.

Posted by: hendric Jun 27 2011, 06:47 PM

I asked about my image with 5 objects marked, and it looks like many of those are likely variable stars. Pamela told me it'll be extremely unlikely to see more than 2 real KBOs in a single image. But here's my favorite one so far: Two KBOs, and two asteroids! (three asteroids if you count the additional one in the next image to the right of this image)

Is it sad that I can sometimes recognize previous Fields of View when shifted or subtracted? Probably!

But still fun!

Posted by: ElkGroveDan Jun 27 2011, 07:52 PM

Does someone want to show me some distinct examples of variable stars verses KBOs? I think my hit-rate is too high.

Posted by: Stu Jun 27 2011, 07:58 PM

Whooosh...!

Have to be honest, I'm pretty addicted too. Unlike the other projects like this, you actually get a "Yes!" Discovery Moment, which is what makes you keep clicking, and clicking, thinking "Just onemore... just one more..."

Posted by: nprev Jun 27 2011, 08:12 PM

Dan, re variable stars: No real idea how to filter them out during the initial screening, and apparently neither does the project at this time; looks like they're going to rely on follow-up observations. I've been thinking that most variables are going to appear more point-like than a KBO, but this might not be a valid assumption based on the occasional glimpses of unprocessed imagery around the edges of the main images...they ALL look like KBOs there!

Posted by: elakdawalla Jun 27 2011, 08:19 PM

I would assume that all light sources in these images are points of light -- remember that we can't even resolve relatively big Pluto as a disk, so the size of KBO you're looking for wouldn't be resolveable as a disk with even the most powerful of telescopes. They are spread out not because they are disks but because the pointlike light is spread out across the detector a little bit for various reasons.

Posted by: nprev Jun 27 2011, 08:25 PM

Yeah, you're right, Emily...it was my best guess.

I & obviously many others would still be very interested in knowing what a realistic detection rate should be. Probably even the project isn't sure yet, though; this is raw science, so of course there are always surprises in the data...

Posted by: centsworth_II Jun 27 2011, 09:49 PM

Maybe one reason is the same as explained in your http://www.planetary.org/blog/article/00000756/ in relation to Deep Impact's exoplanet search?

I sent an email to EPOCh's Principal Investigator, Drake Deming, at Goddard Space Flight Center, to ask him how the search would work. It turns out that he plans to turn Deep Impact's flaw to his benefit....
That's what I call making lemonade from lemons. The camera blur spreads the point-source light from stars out over several pixels on the camera's CCD. Deming explains here how that helps.... "to get high signal to noise, we have to collect lots of photons from the star. That's where the defocus helps. Each pixel of the CCD has a limited capacity to collect photons before it saturates. With a defocused image, we have about 75 pixels collecting light for us, so we can collect lots of photons in each exposure without saturating, and that gives us the high signal-to-noise ratio that we need."

Posted by: ugordan Jun 27 2011, 10:34 PM

I think the point sources are not actually points primarily because of two reasons:
1) telescope point spread function
2) atmospheric turbulence averaged out over the exposure duration

Posted by: john_s Jun 27 2011, 10:36 PM

Yes, variable stars and KBOs are indistinguishable by image size for the reasons Emily gives. But we can distinguish them after all the clicks are compiled because a KBO will produce a series of detections aligned along its orbital path, while variable stars have no such pattern.

Regarding detection rates, we expect there to be a KBO (on any orbit, whether accessible to New Horizons or not) in perhaps every 50th thumbnail, given their known density in the sky. So most of these point sources are going to be variable stars, but at the rate you guys are clicking through them, you've probably nailed quite a few KBOs too.

John

Posted by: nprev Jun 27 2011, 10:55 PM

Timely response, John, thanks!

Okay, so I just did image 3000 with 622 flags for a detection rate of 20.7% (asteroids included, and I'd guess that those represent about 10% of my total, so my KBO rate would be around 18%). Looks like the project is expecting genuine KBO finds in 2% of the images, so my rate is 9 times greater than expected.

Mentioning all this as feedback to the project, is all. This is hella fun, John!

Posted by: ilbasso Jun 29 2011, 03:29 AM

I'm finally gonna be able to see cross-eye stereo pairs after going cross-eyed staring at these images.

I had 5 objects which were perfectly round in one image. Clicked on them all and was sent to an error screen telling me that perhaps I was being over-zealous for selecting 5 objects in one image. But I KNOW they were right!

I'm certain that I am seeing the same star field multiple times per session. I try to limit myself to 50 - 75 screens per session so that I don't get a massive headache.

It would be nice if we could enlarge the image on the screen. I have a lot of screen real estate that is not being used. For us folks with older eyes, it would be a real blessing if we had the option to make the image 25-50% bigger.

Posted by: Explorer1 Jun 29 2011, 06:03 AM

Can you use keyboard commands (like the ones that make browser text bigger)? For example ctrl + or ctrl and mousewheel (on my keyboard at least).

Posted by: ilbasso Jun 29 2011, 03:20 PM

Thanks - the CTRL+mousewheel worked this time. It didn't work the first several days I tried it. Perhaps updating my browser and clearing the cache reset something that was screwing things up.

Posted by: hendric Jun 29 2011, 03:43 PM

You must have seen the same image I did with 5 objects. I also got the note about selecting too much, but talked to Pamela and she said that those are legit selections, but that they are most likely variable stars. I don't think the variable star database will compare with Kepler, but it might still be interesting to someone.

Is this what you saw?

Posted by: centsworth_II Jul 3 2011, 05:00 PM

Up to 2500 views now and this is easily the most artistic (and one of the least scientifically useful) images I have seen.

I don't know a lot about art but I know what I like.

Posted by: pjam Jul 3 2011, 06:36 PM

That's a beaut cents! ...& Just think of the marketing value -postcards, coffee mugs, caps etc.

I just joined -found what look like two near field asteroids and ~24 variables/KBOs in 96 images. Let's see if my "find" rate stays the same for the next 96...

Posted by: centsworth_II Jul 4 2011, 12:03 AM

Up to now I haven't felt the need to break my viewing rhythm to use the click-on list available for comments on image quality, but for some reason a lot of horrible images (and not very artistic to my eye) have cropped up and I've been clicking on the "Simply terrible image" comment a lot. I gave up after about twenty unreadable images in a row. Tried again later and still about half the images are useless. I saw nothing like this in my first 2500!

Yuk!

Posted by: Holder of the Two Leashes Jul 4 2011, 01:28 AM

We may be getting the leftovers no one else wanted (here's a good place to quit and loggout), or they may have been deliberately presenting the better images first in order to get the best return soonest, or both, or something else. I've been noticing it too, but I still get the occasional good image.

Just today, I had to quit when I got some kind of terrible SQL violation error. I'm heading back to see if I can get back on.

EDIT at 45 past the hour: Okay, I can't even get logged on. Anyone have any idea what this is about:

Warning: mysql_connect(): Unknown MySQL server host 'zoobuilderdatabases.cvqgcgieedcl.us-east-1.rds.amazonaws.com' (2) in /home/zoobuilder/public_html/icehunters/admin/database_functions/mysql_functions.php on line 5 Unable to select database icehunters. Please verify the name is correct in admin/zoo-config.php

Posted by: maschnitz Jul 4 2011, 02:09 AM

(Software engineer here) That, there, is a failure of the Amazon AWS service Ice Hunters is using as their server backend. Or a misconfiguration to same.

AWS is basically a way to rent time on central computers. Unfortunately, sometimes, they go down. You also have to get the names exactly right.

Posted by: Holder of the Two Leashes Jul 4 2011, 02:19 AM

Okay, thanks maschnitz.

Time to find something else to do tonight.

Posted by: centsworth_II Jul 4 2011, 09:23 AM

Just got through about 150 more mostly problem free images and then hit another patch of unreadable ones. Gave up again after about twenty. I hope my marking those as "Simply terrible" helps weed them out. If I knew for a fact that it did, I might hang in there longer and mark more "terrible" ones.

I just started paying attention to the counters at the lower left of the screen. The count changed by 5 to 8 after each time I clicked "done" so I guess that was about how many of us were counting at the time. The count change then dropped to 2 or 3 just before I quit. I guess others were dropping out as well.

When you first start counting, the count really jumps around. It takes a string of 50 or so image views before the count settles down to a fairly constant change.
Edit: Or not. Sometimes the count flips back and forth between trend lines a few hundred counts apart.

Posted by: centsworth_II Jul 4 2011, 05:28 PM

A near miss!

Close to you...

By the way, it's been clear sailing with nary a bad image on my current ice hunting expedition.

Two asteroids!


Overlapping KBO/VARs?


This is getting ridiculous! All this in one sitting?!

Posted by: Greg Hullender Jul 4 2011, 07:51 PM

I find I'm marking about 1.5 objects per frame. From my own background in ML and data labeling (plus the note on the page to overlabel) I'm guessing this is just fine. It hugely reduces the space requiring followup, and that's probably all that's wanted/needed.

I have a bit more trouble with the labeling of image quality. I realize those are of only secondary value, but I do like to do things right.

--Greg

Posted by: nprev Jul 4 2011, 08:18 PM

I've only been rating image quality if I get a streak of real garbage pics on the theory that it might be a bad batch. The occasional lemon...well, that just happens.

Posted by: nprev Jul 4 2011, 08:42 PM

Here's today's best shot for me: asteroid & big honkin' KBO/variable star. John, question: Is there an expected detection rate for variables? Would like to know as a vector check for our respective discovery rates.

Posted by: Greg Hullender Jul 4 2011, 09:02 PM

I'll bet that when you first start, they give you a bunch of pix that had likely KBO/Variables in them. That both lets you come up to speed and lets them get an idea of how good you are at it. Somewhere around 150 images, my find rate for KBOs dropped drastically. (I stopped at 300--my hand hurts.)

When I click the "My Icehuntings" link, I see that nearly everything I've marked has also been marked by 8 to 16 people, so I'll guess I'm on the right track.

The rules I developed for myself are more or less as follows:

1) Don't click really little ones.
2) Don't click if it has even a single black pixel completely inside it.
3) Don't bother with asteroids unless they're very obvious.
4) Just skip bad pages--don't try to say why. (Did I mention my hand hurts?) :-)

I think they ought to give us keyboard shortcuts for all the buttons; minimizing mouse movement really helps reduce RSI.

--Greg

Posted by: nprev Jul 4 2011, 10:16 PM

I agree with all your rules save #3, Greg; I think that the faint ones are by far the most likely new discoveries.

Posted by: ngunn Jul 4 2011, 10:36 PM

Like many, I find this a really exciting project. I'm interested in how it was set up, and your surmises suggest that we may not have been fully informed about what we would be 'fed' and what would be done with our responses. If true, that's unfortunate. Are there things we don't know about how our input is being used? This is a technique employed by psychologists but surely not necessary here. So, NH team (and I know you are our friends), is Greg right?

Posted by: centsworth_II Jul 4 2011, 11:50 PM

As you can see in my last post I just went through a really productive stretch, and that was as I neared 4000 images viewed. I've been through dry stretches and productive stretches and stretches of unreadable trash, but I have no reason to think it's anything but chance.

http://www.unmannedspaceflight.com/index.php?s=&showtopic=5368&view=findpost&p=173210 "...we probably will add artificial objects 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."

So there may be artificial objects in some of the images, but I doubt that the images are fed in any particular order to any particular person.

Posted by: Greg Hullender Jul 5 2011, 01:05 AM

Why do you say that? It's a very sensible thing to do. When people are new to the task, it makes sense to give them plenty of well-understood images. I'd expect to have to discard the first few dozen from each person anyway. People are great at this sort of task, but a) they take time to master it and b] they benefit from a little help.

Once someone is up to speed, then it makes sense to turn them loose on the less-well-understood stuff. But almost all human data labeling protocols I know of have an enrollment period. There's nothing wrong with that.

--Greg

Posted by: Greg Hullender Jul 5 2011, 01:35 AM

I think these are really bad subtractions. What I want is a simple "bad image" button to indicate that I gave up on it. I might have marked one really obvious one, even on a bad image, but even then it should be taken with a grain of salt.

I also want keystrokes. E.g. press the spacebar for "done marking" and (maybe) press "X" for "bad image." Anything to minimize use of the mouse.

Given nprev's comment that bright asteroids will already be known, I've quit marking them entirely. They take too much time, and they're not what we're there for.

--Greg

Posted by: ngunn Jul 5 2011, 07:40 AM

Nothing at all, if it's signposted so that participants are fully briefed about how it's working and when they're entering a different phase.

Posted by: centsworth_II Jul 5 2011, 12:52 PM

Tic Tac Toe

Posted by: Greg Hullender Jul 5 2011, 02:13 PM

I'm baffled that anyone would care--other than curiosity about the process. If you look back through the record of how well your votes correlate with others, you'll find some with a dozen or more prior votes and others with no one but you. Clearly there has to be some algorithm that decides when to give you a pic to help validate and when to give you one that no one has seen before. Since part of the draw here is potentially getting credit as the discoverer of an object, it's essential that everyone gets a fair chance at new images, but that's about the only legitimate concern I can think anyone could have about any aspect of the process. Certainly the idea that participants have a "right" to know the selection algorithm makes no sense; the researchers need to be able to change that algorithm depending on how its working. For test purposes, they'd probably want to try out a new algorithm on a subset of the users. I see no reason why they should announce any of this, unless it was something especially cool that they thought people would be interested in.

--Greg

Posted by: nprev Jul 5 2011, 02:51 PM

Greg, I would still mark the bright asteroids. Remember, "bright" is a relative term here; Alan said a few months back that the limiting magnitude of these images is 28 (!). Probably the brightest thing we see here is around 14th magnitude or so, which is the same approximate brightness as Pluto seen from Earth.

Posted by: john_s Jul 5 2011, 05:07 PM

There's no fancy algorithm for who gets to see which images, other than to ensure that all images are seen by a sufficient number of people. However I think there may have been some prioritization of the order in which the images were presented after the public release, with some of the better subtractions being put up first, which might explain why some people are hitting a "bad patch" after initial smooth sailing.

We are still working through the 2004/2005 preliminary search data, because (as always happens, even when you plan for it...) the 2011 data are taking longer to process than we'd anticipated. So there are still no artificial objects in the data.

And yes, please click on the faint objects too- our chosen target is likely to be faint, unless we're really lucky. But almost everything in these images, asteroids as well as KBOs, is likely to be new, as nprev said. The limiting magnitude in the data currently posted is about 25.5, and most things you see (apart from those "artistic" super-saturated stars) are probably fainter than mag 18 or something like that.

I'm surprised myself at how many variable stars are showing up, but I have no idea how many we should expect- dammit, Jim, I'm a planetary scientist, not a real astronomer... It's possible that we are learning something new about variables, though- there probably haven't been many surveys that go this deep in the Milky Way.

The keyboard shortcut idea is a good one- I'll pass it along and see if there's any chance of implementing that.

Thanks again for everyone's help with this!

John

Posted by: nprev Jul 5 2011, 05:22 PM

Thanks for the thorough response, John. "Dammit, Jim"...

Posted by: ngunn Jul 5 2011, 07:13 PM

Ditto from me. Much appreciated.

Posted by: Greg Hullender Jul 6 2011, 03:54 AM

Likewise. I'll wait until they keyboard shortcut (if it comes) before doing more; I probably overdid it yesterday (I did 600 some) and I was in pain most of today. (I should know better, but I got into it.) :-)

--Greg

Posted by: tasp Jul 6 2011, 02:09 PM

I heard the Subaru telescope was damaged by a coolant leak.

Does this impact KBO search?

Posted by: john_s Jul 6 2011, 02:59 PM

Yup, we were on the telescope that night- the first night of a two-night run. Fortunately the problem happened at the end of that first night, so we got one night of great data, but of course we lost the second night. Our drive back down the mountain in the morning was delayed by about an hour as the telescope operator tried to figure out what the heck had gone wrong- he was getting all sorts of error messages that he'd never seen before...

That was our last Subaru run for the year, so no further impact on our program from the anomaly. But I hope it's fixed soon, for the sake of all the other observers.

John

Posted by: hendric Jul 6 2011, 03:16 PM

Looks like it was ethylene glycol & water - good news is that it is non-corrosive, and if the water's pure, non-conductive as well. By the color, it looks like the same stuff GM recommends for their radiators.

http://www.universetoday.com/87245/subaru-8-meter-telescope-damaged-by-leaking-coolant/

Posted by: tasp Jul 6 2011, 04:45 PM

Thanks for the update.

Hope they can get coolant mess sorted out and back to observing. Saw a picture of the mirror with the coolant on it, gosh there is a quite a bit of fluid.

Is the coolant for the electronics or the drive mechanism for the scope? (perhaps if it was for the electronics it would have less particulates entrained in it?)

Posted by: Gsnorgathon Jul 8 2011, 02:14 AM

The "reviewed"/"for follow-up" counters are showing now. The "for follow-up" rate is almost 30%! I'm really looking forward to the "confirmed new KBOs" counter...

Posted by: centsworth_II Jul 11 2011, 04:08 AM

I'm surprised that finding objects is so easy in these images. I'm assuming there were fewer background stars in 2004/2005 than in 2009/2010? Will the background in the 2011 data be similar to 2004/2005 or less cluttered?

So far it looks like a quarter of the objects found have been reviewed and about 1 in 3 of those reviewed have been marked for follow up.
(I'm assuming that asteroids are included in number of objects found but not in objects marked for follow up and fudged my estimate accordingly.)

Posted by: john_s Jul 11 2011, 03:04 PM

The one thing I can say about background star density in the 2011 data is that it is more uniform- in 2004/2005 we were moving in and out of the dust lanes near the galactic equator, while now we're (slowly) moving away from the equator, through unobscured star fields. We're also using longer exposures, so we're picking up fainter stars. Nevertheless, most of the 2011 images show a fair amount of "clean" sky between the stars when seeing is good, so I think the KBOs won't have many places to hide.

John

Posted by: centsworth_II Jul 11 2011, 06:33 PM

Thanks for the preview. I'm enjoying going through the current images picking out "objects". I wonder how many will survive the great purge that awaits when comparisons with the 2011 data begin.

Posted by: Greg Hullender Jul 12 2011, 04:49 AM

Has anyone taken a look at their own contributions to see how many have been marked for followup? Something like 90% of mine seem to be marked for followup (not counting the 100 I did just this evening). That seems awfully high, given that they haven't even reviewed most of the objects found yet.

Or maybe it does make sense; even if all of us are 90% accurate, but when we're wrong, it's random, then you'd expect that if 30 of us looked at the same plate, 27 of us might label the same object, and three would label random garbage. So we'd all see great personal results, even though 75% of the objects we identified weren't suitable for followup.

It'd be cool to see more stats.

--Greg

Posted by: centsworth_II Jul 12 2011, 04:59 AM

Even some very faint objects aren't getting past Icehunters' scrutiny.

Some of the less subtle objects also capture attention -- for less than scientific reasons.

When I saw this:


I thought of this:

Posted by: stewjack Jul 12 2011, 06:17 PM

I mark objects like that all the time, but I rarely get more than one other person to agree with me. In fact that may be one of mine! You could argue that they are "grey" not "white," but if I click on the "change contrast" button, and the object looks white - then I mark it. However, it must remain "blob like," and not become square-ish or pix-elated with the increased contrast.

163 found in
324 images

Jack

Posted by: Greg Hullender Jul 17 2011, 04:01 AM

I just finished my 1000th screen, so I thought I'd make some more-specific suggestions to make the tool easier to use.


1) As I said before, I want to press "space" to advance to the next screen instead of having to click a button with the mouse. If I press space without having marked any objects, that means I think there's none there.


2) Also like before, I'd like to press "b" to advance to the next screen AND signal that something was wrong with the current one. The new twist is that I may have clicked some objects anyway. That makes sense; many of the images aren't entirely wrecked, but "b" signals that I think they need to retake the picture.

3) Instead of an asteroid button, I'd like it if I could just click once to circle something, then click inside the circle to change to an asteroid, and then click a third time to erase.

4) I wish the application would start loading the next screen in the background so I didn't have to wait so long.

5) I wish I could go back one screen; sometimes I see an object AFTER I've clicked next, but there's nothing I can do about it.

Does anyone know how to contact the team that manages the app? I looked all over the site (and posted some suggestions there) but I didn't find an obvious way to send feedback.

--Greg

Posted by: ElkGroveDan Jul 17 2011, 04:12 AM

I agree with #5.

Posted by: dilo Jul 17 2011, 08:05 AM

I agree too, especially on last 3 points!

Posted by: nprev Jul 17 2011, 08:13 AM

I aqree with #5 as well; had that happen several times, and it just kills me!!!

Posted by: NickF Jul 18 2011, 03:32 AM

I flick the mouse pointer away from the 'done marking' button after I've clicked it. That stops my 'click throughs'.

Posted by: centsworth_II Jul 19 2011, 10:27 AM

I feel y'all's pain, believe me. I've missed more objects than I care to admit. But that's part of the "game".
From http://www.icehunters.org/faq


You may agree with their reasoning or not, but there it is. It is possible to come to terms with -- even be at peace with -- the lack of a "back" button, but it involves a denial of the human ego, setting aside any perfectionist tendencies, and embracing the notion that you are but one of an army of worker ants moving toward a communal goal.

Posted by: stewjack Jul 19 2011, 04:08 PM

NOTE: This post is only for IceHunters or people interested in IceHunters. Perhaps we should start a new thread?

IMO: That is the secret of this science for dummies, (ie. human-beings). project. Accuracy takes time and effort. Even highly trained or dedicated people can get bored or distracted. With IceHunters, every image is checked by a minimum of eight people, and they overlap images, so I suspect each area of your image is checked by a minimum of 16 people! Normally, within about five minutes of clicking the [Done Marking] button eight or more people have completed the image and the results are reported.

Note: Sometimes overlap image results are also reported at the same time, but I don't fully understand what I am seeing. This is because the data from overlap images is not labeled clearly. It is only obvious that overlap image results are being reported when the same object is reported twice by two separate groups of three or more individuals. It seems to me, that would have to be from two different images.

Personal Example: When I compared my identified objects against a large number of final group results, I found that I was missing about one object for every 9 or 10 objects the group found. Also I was reporting about 2 objects that those same group results had never noticed or at least accepted as possible KBO's.

I find these result acceptable.especially for missed objects. I would be interested other peoples reasoning.

Note: At the present time, only ~28% of the objects that have been reviewed are found acceptable for follow-up by the reviewer.

Jack

Posted by: Greg Hullender Jul 20 2011, 03:35 AM

I didn't realize they had done it on purpose. I've supervised data collection and labeling efforts at four different companies over the past thirty years, and, in my experience, lack of a back button is a mistake. The reason is, people are uncomfortable with an irreversible decision. They go *faster* if they have the option to go back--even when they never actually use the button.

That said, this is a much, much faster task than most of the kinds I've supervised, so the user has a lot less to lose from a mistake. Accordingly, it might not make as much difference here. I don't believe it would make things worse, but the positive benefit might be small in this particular case.

Far and away the biggest problem is the lack of keyboard shortcuts, which makes it an RSI hazard. Everything else is really secondary.

--Greg

Posted by: centsworth_II Jul 25 2011, 04:16 PM

In response to a request by the science team, Icehunters are really getting serious about finding faint objects!

Posted by: Greg Hullender Jul 26 2011, 12:04 AM

Yes, and now it makes sense to use the contrast button. It really makes the faint objects pop!

--Greg

Posted by: centsworth_II Jul 27 2011, 01:50 PM

By the way, for anyone here that may be Icehunting but not reading the Icehunter forums, here are http://talk.icehunters.org/discussions/DMZ100006j?page=1&per_page=10 I still mark the bright ones because its good to get all the variable stars into the data base (and who knows, it really could be a huge KBO!).

Posted by: tfisher Jul 30 2011, 02:30 PM

Does anyone know how far a genuine KBO is likely to have moved in the icehunter images? I've been trying to watch for white/black blob pairs. After 1000+ images, my current favorite bet in the objects I've marked to be an actual KBO is this black-white pair (as seen in positive and negative -- I got both )

http://www.icehunters.org/object.php?id=515823
http://www.icehunters.org/object.php?id=515965

I'm curious, though, for the image pairs being subtracted what is the range of motion for an actual KBO between the images?

Posted by: john_s Jul 30 2011, 03:21 PM

Pairs can be anywhere from a few hours to a few days apart, and at opposition typical KBO motions are 3 arcsec/hour or 15 pixels/hour. So motion is likely to be tens to hundreds of pixels.

Sometimes an apparent pair results from a CCD defect that is fixed on the camera, but moves slightly when the images are shifted to line up the stars. It's possible that's what you're seeing here. Or, it *might* be a KBO if this pair was taken unusually close in time.

By the way, we just got the first 2011 data through the differencing pipeline, and expect the new images to be posted on the Zoo very soon...

John

Posted by: tfisher Jul 30 2011, 03:50 PM

Thanks, Dr. Spencer!

So maybe I have a better chance with my second-most-favorite guess at a real KBO:
http://www.icehunters.org/object.php?mid=290587

That gives a pair with nice equal-looking-magnitude with ~36 pixel separation.

Posted by: pjam Jul 31 2011, 02:12 AM

...In one case I saw an even pair that was clearly separated but not easily marked by one circle. So I used two circles to mark them ...is this OK or perhaps just confusing?
-pjam

Posted by: john_s Aug 10 2011, 04:40 PM

Just to let everyone know that the first 2011 KBO search data are now posted on the http://www.icehunters.org for your searching pleasure. Currently we've posted the early June 2011 data set from Subaru (without seeding with artificial KBOs, for now), to be followed later by the early July Subaru data and the late May / early June data from the Magellan telescope.

Have at it! We'd love to have some preliminary candidate KBOs in hand when we apply for 2012 telescope time starting in mid-September. And thanks again.

By the way, there's a http://www.pluto.jhuapl.edu/news_center/news/20110805.php from me describing our July Subaru run on the New Horizons site (it's also http://blogs.zooniverse.org/icehunters/2011/08/02/catching-the-light-of-a-kbo/ on the Ice Hunters site, but with fewer pictures ).

John

Posted by: alan Aug 22 2011, 08:12 PM

Icehunters now has many of the reviewed objects identified as variable stars.

Posted by: alan Oct 15 2011, 06:20 PM

Some are now marked as KBO - confirmed including a couple of mine
http://www.icehunters.org/object.php?id=709316
http://www.icehunters.org/object.php?id=709333

Posted by: centsworth_II Oct 15 2011, 07:41 PM

Looks like you need to be logged in to IceHunters to see those images linked by alan, so here they are:

Posted by: centsworth_II Oct 15 2011, 07:46 PM

And here is a field showing three confirmed variable stars and a confirmed KBO (VS circled red and KBO circled green in the inset).
Also there is a forum exchange with a member of the science team.

Posted by: alphasam Oct 16 2011, 06:49 AM

Haha, yeah that was me trying to point out the faints need marking too. Still seems a lot of people are only marking the obvious ones.

Four of mine are confirmed KBOs so far.

Posted by: Adam Hurcewicz Oct 16 2011, 04:36 PM

Hi,

I was wonder how many KBO's potential targets to New Horizons, and make this grafic.

I downloaded MPCORB dated to 16 Oct. 2011 (566207 bodies) and view only that who
are d > 30 AU ( d - distance from Earth )

I use Guide8 software, there are no r limitations ( r - distance from Sun )

So, it's no good for NH and it's potential KBO targets

Posted by: stevesliva Oct 16 2011, 05:06 PM

It's interesting to poke around the forum there... seems these first confirms may be because they're identified in a 3-point arc?

Posted by: Adam Hurcewicz Oct 17 2011, 01:02 PM

I add this asteroids to Celestia soft and made animation
http://www.youtube.com/watch?v=ycDOYLjgWQs


---
Mayby it's time to search this way for comets ?

Posted by: hendric Oct 17 2011, 07:12 PM

Adam,
That's to be expected. In general, KBO searches have been avoiding this area, because of the large number of background stars. You can see some of what the raw fields look like on the edges of pictures. Their algorithm subtracts two images from each other, but can leave large residuals that are difficult for a silicon computer to deal with, but fairly easy for a carbon one. So don't be surprised that the area around Pluto is empty, they've only just begun searching!

Posted by: nprev Oct 17 2011, 10:05 PM

I got one confirmed out of 3568 images, and six marked as "Likely KBO/Variable Star".

Posted by: stevesliva Oct 25 2011, 12:49 AM

And they're going to followup on that sort of faint object, too:
http://www.icehunters.org/image.php?id=59777
http://www.icehunters.org/image.php?id=59781
http://www.icehunters.org/image.php?id=59382

I have to say that with so many distracting (now confirmed) variable stars, I wasn't looking for stuff this tiny.

Posted by: hendric Oct 25 2011, 05:38 PM

With a database of variable stars, will you be able to pre-mark the known variables in future images?

Posted by: antoniseb Oct 26 2011, 07:07 AM

I was looking for stuff that tiny, and found quite a few, but the majority of the images they gave us were so noisy or messy that such small things couldn't be spotted.

Posted by: stevesliva Oct 26 2011, 05:06 PM

That is true. This slew of images was repeats. Those things were flagged for followup even before I tagged them.

Posted by: centsworth_II Feb 3 2012, 02:05 PM

After a prolific start (almost 19,000 images viewed) I have to admit I've been away from Icehunters for awhile. I finally check back in and see this :

Checking the Icehunter forums, it seems that people are waiting for a list of identified KBOs. This is that latest pertinent information I could find:

Posted by: john_s Feb 3 2012, 05:26 PM

Yes, all the Subaru images from 2004/2005, and from 2011, have now been searched, and a bunch of KBOs have been found as a result, though so far none are obvious targets for New Horizons. A list of discoveries, and official thanks to all the volunteers, will indeed be posted soon.

There will probably be additional posts in the next few months of some of our Magellan data on a new site, CosmoQuest, which will have much the same functionality as IceHunters, so stay tuned.

Thanks again to everyone,
John

Posted by: stevesliva Feb 3 2012, 05:42 PM

Has there been more extensive review beyond this?


The number "reviewed" hasn't changed in quite awhile, and sure enough, it seems that I can go in an find big beautiful blobs marked by 45 people that seemingly are marked only as "likely KBO / Variable Star" which would seem to indicate it's not been sorted into the review/not review piles yet.

Posted by: john_s Feb 3 2012, 10:58 PM

I've not been doing those reviews or updates, so I can't answer directly, but I do know that essentially all the data generated by Ice Hunters has been sorted through, and the real KBOs have been extracted and compiled. We are however behind in posting the results, and we're working on fixing that.

John

Posted by: centsworth_II Mar 9 2012, 07:11 AM

Yay! The http://www.icehunters.org/ are up and I was among those marking three of the confirmed KBOs. The first to mark one of them!

I don't know who this Sergei Schmalz guy is, but he was the first to mark at least 5 KBOs. It would have been 6 but I beat him by two minutes on one.

A good tip for those looking for a particular screen name was http://talk.icehunters.org/science/kbos/discussions/DMZ10000ds "most browsers have a find function, use ctrl+f then type your username." This worked for me using Firefox. Note that you need to re-click on "highlight all" for each page.

Posted by: brellis Mar 9 2012, 08:14 AM

Hero! Total hero! Nicely done

Posted by: ElkGroveDan Mar 9 2012, 08:38 AM

Looks like Nick (NPrev) got one: IH-105036 (KBO) which is on page four of the current layout.

EDIT: also Ian_Regan, TASP, tdemko, and antoniseb .... (that I recognize anyway)

Posted by: Marz Mar 9 2012, 03:47 PM

congratulations to the discoverers and to the IceHunters Team for the success of this project!!

Alas, my objects are all stars, 'roids, or unclassified... no KBOs for me.

Why does the asteroid gallery say "no orbital elements"? I would think they would be easier to determine than the KBO ephemeris, and it would be interesting to know what type of asteroids they are. I realize that's not useful for New Horizons, but isn't there the potential for follow up observations to confirm these too?

I wonder what "unclassified" implies? I'm sure some of these might be hot pixels or cosmic rays, but some really look like diffuse KBOs. I wonder if these are image artifacts, or if there was not enough information to classify them and could potentially be an interesting object?

Posted by: centsworth_II Mar 9 2012, 04:35 PM

"Hero"

Well... I didn't save any lives, or feed the poor, or.... but it is nice to think that somewhere out there is a chunk of ice that I was the first to see (by two minutes.)

I found the timeline of discoveries interesting. All three of the KBOs I featured in my previous post were "discovered" over a span of just 45 minutes.

I thought it would be more like what we see below. The time-span from first to last discovery is seven months. What an age we live in when some of the most sophisticated machines built by man can take pictures of space objects that are then put on the internet where one is discovered by SickChick79!

Posted by: stevesliva Mar 9 2012, 07:36 PM

Gnsorgathon was the sole discoverer of one... I'm not sure how that sort of thing got followed up? There were a few others. Perhaps the mark was in line with some others?

Posted by: stevesliva Mar 9 2012, 07:55 PM

Me too. Though I'm tied for first on three "Asteroid IDs," whatever that means. Not sure if it means they simply look like an asteroid, or if they've been correlated with a catalog, or if they precovered or observed them elsewhere...

Posted by: hendric Mar 9 2012, 08:20 PM

I got me a KBO! I'm pretty surprised actually, I only had ~3k images searched.

http://www.icehunters.org/object.php?mid=77557

I shall keep it, and pet it, and name it George!

Edit:
re: Asteroids not having elements

Here is a response from Pamela (sic):

starstryder (admin) in response to gonano
The times are all there because people wanted to know who found things first. If we had sufficient data to get orbits fro the asteroids (and we don't seem to) then it would matter for naming. As it stands, it's mostly the "OH COOL - I saw it first" factor.

So, it's really just bragging rights, but I think that's cool in it self :-)

Cheers,

Pamela

Posted by: stevesliva Mar 9 2012, 08:25 PM

I had 1441 images. Looks like statistically (from some stats by a forum user), you could reasonably expect 1 in 2000.

Posted by: centsworth_II Mar 9 2012, 09:03 PM

Going for spousal brownie points, telling my wife I discovered it for her. http://en.wikipedia.org/wiki/International_Star_Registry can go suck it!

Posted by: Gsnorgathon Mar 9 2012, 10:05 PM

I hate to think what my false positive rate must be for me to have spotted that one... but to be the only one who did? I'll have to start wearing knit hats because I won't be able to get a regular one big enough!

Posted by: Seryddwr Mar 10 2012, 06:27 PM

Just a quick question - did anyone else experience trouble in creating a Zooniverse account when they began hunting KBOs? I'd like to help, but I can't seem to register for some reason.

Posted by: RJG Mar 10 2012, 11:16 PM

Looks like I got one too! First to spot it (by 38 seconds!). IH-267996.

...but will it get a visit?

Posted by: tasp Mar 11 2012, 12:34 AM

Oh, my.

Whodda thought? It was quite difficult going through those pictures and not wanting to flag every little blip, but not wanting to miss maybe a significant little nugget either.

I assume most of these 'rocks' won't get much in the way of follow up observation time unless they look really primo for a NH encounter. Still, if any of them have odd or unexpected orbital inclinations or eccentricities, it would be interesting to know and compare to some of the other unusual ones we already know about.

BTW, for the objects with multiple images, are there any unexpectedly large brightness variations among the images? Seems like a large brightness variation might be indicative of global dichotomy or an elongated object, making for an object a little more interesting than the others.

Hoping the NH team gets a real gem or two for the extended mission!

Posted by: stevesliva Mar 11 2012, 03:57 AM

You have to remember that the discovery "images" on icehunters are not single images, but algorithmic mergers of several. I don't think you can address the questions you're raising from them.

Posted by: tasp Mar 11 2012, 04:06 AM

OK, thanx for that.

Posted by: centsworth_II Mar 11 2012, 04:52 PM

I don't know about the registration problem, but there are no new images to analyze right now. From these posts in the IceHunters forum, I gather it may be weeks - or months (depending on what "a while" turns out to be) before new images are available and when they are, the search may continue at a different web site: http://cosmoquest.org./

Posted by: Seryddwr Mar 11 2012, 11:02 PM

Thanks for the reply. It turns out I couldn't register due to the maddening technical hitch of my being unable to read simple English...

I managed it in the end, thank goodness. It's a fine site. I am thinking about helping out with the 'planet hunters' project in due course - or while we wait for another cache of KBO images!

Posted by: alan Mar 13 2012, 04:28 PM

4 for me, one I missed being the first to spot by 3 seconds

Posted by: antoniseb Mar 14 2012, 09:51 PM

I didn't figure out how to search just for ones that I'm listed on, but I looked through the roughly 150 confirmed KBOs and noticed my ID on three of them. I'd gone through about 20,000 images, so by the above suggestion should have seen about ten, but it is hard to know, and I'd have to say a large fraction of the images I searched were unusable... so maybe three is right.

Posted by: stevesliva Mar 15 2012, 01:43 AM

^ The poster on the forum at icehunters said (s)he'd started late, so some of his 1-in-2000 "discoveries" were no doubt images be refloated to the top of the queue to get more looks. Indeed there were probably a lot of images that got skimmed by a few people and then thrown out of circulation.

Posted by: centsworth_II Mar 22 2012, 01:10 PM

Just noticed the following in the IceHunters forum.
I used the starstryder@gmail.com address and got a form e-mail back saying Pamela was traveling. I see nprev on the Name Needed list in case anyone wants to get word to him.

Posted by: centsworth_II Mar 24 2012, 02:46 PM

Just found out myself. Clicking on the "?" in upper right on the catalog pages gives general information including, "Scientist Confirmation: Scientists review all marks - even those with a single click (but those are de-prioritized)." Objects with three clicks were reviewed first.

Posted by: alan May 3 2012, 06:34 PM

http://www.lpi.usra.edu/meetings/acm2012/pdf/6430.pdf

Posted by: SFJCody May 3 2012, 10:52 PM

Will these get minor planet temporary designations?

Posted by: Marz Jun 16 2012, 09:18 PM

Here's the wording from the FAQ:

"How do the results get published?

Kuiper Belt Objects: All discovered KBOs will be submitted to the Minor Planet Center. The submission will be led by the scientists who are making all the observations, reducing the data, and calculating all the orbits. Within the submission, the name of every person who marked a discovered KBO will be listed. We will also maintain a catalogue on this site of all the discovered objects and all the discovery makers. Please note: Due to the restrictions on how things can get submitted, we can only include real last names and initials. We cannot use online alias.

Variable Stars: All discovered variable stars will be catalogued and submitted for publication in a to be determined journal. The submission will be led by team scientists and each object will be listed with the names of the individuals who discovered them.

Asteroids: Most of the objects noted by this project do not have sufficient data to calculate orbits. If sufficient data is achieved for any of our asteroids, they will be submitted to the Minor Planet Center and the discovery team will be allowed to name the object. "


FYI: there's new images to work on at http://cosmoquest.org/iceinvestigators/

Posted by: centsworth_II Aug 6 2012, 03:42 PM

An http://cosmoquest.org/blog/2012/08/new-horizons-kuiper-belt-fly-thru/ of KBOs so far found along New Horizon's path. Right now there are no new images to view in the KBO search... more coming in the future.

Posted by: Explorer1 Aug 7 2012, 04:45 AM

Anyone else getting a real Star Wars vibe from those sound effects and visuals?
Just need a lost TIE fighter now...

Posted by: john_s Aug 8 2012, 07:36 PM

Also, check out the webcast videos on the New Horizons web site, about our July 2011 KBO search observing run on the Subaru telescope on Mauna Kea:
http://www.pluto.jhuapl.edu/gallery/videos/podcast.php

John

Posted by: Paolo Aug 21 2012, 09:51 AM

posted a few minutes ago on NewHorizons2015 twitter:

Posted by: remcook Aug 21 2012, 10:51 AM

Oh, that would be nice! Looking forward to the details.

Posted by: tedstryk Aug 21 2012, 01:53 PM

Looking forward to seeing what this is...distant flyby can mean a lot of things.

Posted by: Phil Stooke Aug 21 2012, 03:53 PM

"FLASH! Our possible KBO encounter in Jan 2015 is not a close flyby-75 million km off-but there's science in it no other observatory can do! "

Not a close-up!


Phil

Posted by: Paolo Aug 21 2012, 04:45 PM

also:

Posted by: stevesliva Aug 21 2012, 05:44 PM

Just light curves? Or something more like resolving satellites?

Posted by: Paolo Aug 21 2012, 05:52 PM

probably characterization of a KBO at phase angles impossible from Earth

Posted by: algorimancer Aug 21 2012, 06:20 PM

I wonder whether it would be feasible/worthwhile to have the New Horizons spacecraft itself performing an ongoing active search for targetable objects, then perform an autonomous imaging campaign, kind of like the MER rovers could be configured to scan for dust devils and record them. Possibly this mode would be better left until after the Pluto flyby. Years ago this thought occurred to me with regard to the Voyager probes, but that was shortly after they permanently disabled their cameras.

Posted by: Phil Stooke Aug 21 2012, 07:55 PM

I would have thought it could not possibly go as deep as a big ground or orbital telescope... and it wouldn't work during hibernation periods.

Phil

Posted by: algorimancer Aug 22 2012, 04:08 PM

Agreed, but it could potentially catch smaller/darker objects which the ground/orbital telescopes would miss, when it is close enough to them -- which is why it would likely need to be a fairly active search, with capability for quick response. No, this would not work during hibernation periods, but presumably once past Pluto -- since it is nuclear powered and need not ration power -- it can simply be set in an active/automated mode where it regularly looks ahead seeking nearby objects which will be made obvious by rapid changes in brightness/position, then images them as it passes by. This would require little energy, and probably no active maneuvering beyond orienting the cameras to follow an object during flyby.

Posted by: john_s Aug 23 2012, 04:13 AM

Right, our camera aperture is small enough that even though we're closer to the KBOs there's no advantage to searching from the spacecraft. Plus our maximum exposure time is 10 seconds compared to the hours we can integrate from the ground, and it takes thruster fuel to hold the spacecraft steady during those 10 second exposures, so we can't take too many of them. Oh, and because of the need to use thrusters to hold the spacecraft steady, our best spatial resolution for those long exposures is about 4 arcseconds, compared to the ~0.6 arcseconds we can get from the Earth (on a good night). The lower spatial resolution makes it difficult to distinguish and KBOs from all the background stars.

New Horizons would have a sensitivity advantage for KBOs that are very small and close to the spacecraft, as algorimancer says, but we don't think there are many of those, and we don't have the onboard smarts to find them autonomously in the images onboard the spacecraft, and we don't have the bandwidth to send enough of them back to Earth for processing even if we could afford the fuel for all those long exposures...

So we'll just have to keep searching with the big telescopes here on Earth.

John

Posted by: elakdawalla Aug 23 2012, 04:46 AM

John, I was talking to someone at LPSC (and now I can't remember who it was) who was dismissing the usefulness of obtaining lightcurves at high phase angles. Obviously people do think it's useful because New Horizons and Cassini have been doing lots of high-phase-angle observations of unresolved objects. Could you explain what it is you (by which I mean planetary astronomers in general, not just the New Horizons team) hope to learn with these lightcurve studies?

Posted by: machi Aug 23 2012, 08:59 AM

Light curves are useful for many things.
This is citation from abstract http://meetingorganizer.copernicus.org/EPSC-DPS2011/EPSC-DPS2011-1452.pdf, which describes observations of small irregular moons from Cassini.

"Motivation is the determination of basic
properties of these objects like rotation periods, polar
axes orientations, object sizes and shapes, phase
curves, colors, or the search for binaries."

Another field of research is about asteroids and analyzing their light curves for determination of their physical properties.
I saw comparison between two shape models of Lutetia. One was obtained by modeling from light curve and second from Rosetta OSIRIS camera.
Both of them were almost identical (basic shape in low resolution).
High phase observations are useful for Hapke modeling of surface properties as surface roughness etc.
But I think that usefulness of this technique strongly depend on quality and quantity of images.

Posted by: paxdan Aug 23 2012, 10:26 AM

Motivation is the determination of basic
properties of these objects like rotation periods, polar
axes orientations, object sizes and shapes, phase
curves, colors, or the search for binaries

reads like amazing http://en.wikipedia.org/wiki/Blank_verse.

Posted by: algorimancer Aug 23 2012, 01:10 PM

Thanks for clearing that up. I had assumed that reaction wheels were used for adjusting orientation, if thrusters are needed this is clearly a non-starter. I was also a bit concerned that communication would require re-orienting to point at Earth, which would add additional complications. Perhaps someday a similar approach might be tried on a subsequent mission.

Posted by: john_s Aug 23 2012, 07:03 PM

Actually we're more interested in the phase curves than lightcurves per se (lightcurves would be interesting too, to get rotation periods and shapes, but can be done from HST). A rotational lightcurve at high phase angles may be hard to interpret in terms of shape, but is fine for getting the rotation period, which I think is the prime motivation for the Cassini lightcurve observations. For Cassini, I don't *think* there's any preference for high phase angle observations- the phase angle is just whatever it happens to be when there's a block of time available for the observations.

Phase curves (which can't be done from Earth for KBOs) are useful for constraining surface textures. However we also have a practical interest on New Horizons, because we will need to acquire our flyby target KBO at higher phase angles (maybe 20 degrees) than can be observed from Earth, so we'd like an estimate of how bright it will be at that phase angle. The dimmer our KBO is, the less time we will have between our first onboard OpNav and the encounter, and the more fuel we'll need to hold in reserve for final targeting.

John

Posted by: john_s Aug 23 2012, 07:07 PM

Yes, no reaction wheels on New Horizons (I think because they would have required too much mass and power). Thrusters are better than reaction wheels for the rapid slewing we'll need to do at Pluto- they just aren't as good at keeping a spacecraft rock-steady for time exposures, and of course they use fuel.

John

Posted by: TheAnt Aug 28 2012, 03:57 PM

Well at least I did not expect any images taken of "VNH0004" since it will be at a distance comparable to Mars at opposition.
It would take one huge telescope to get a good spectra and even less to resolve anything even if it had been located in the inner solar system.

When one consider that it will have to be for one object that receive ~1000 times less sunlight (about 900 times less at Neptune) it become one daunting task indeed. Even to coerce information out of any possible post-Pluto encounter, that might 'only' be some few millions of kilometers will be quite an achievement - we need to find a possible candidate for anything such first though.

Posted by: Tom Tamlyn Sep 6 2012, 06:46 AM

Voyager's 35th anniversary got me thinking about a possible particles and fields terminal mission for New Horizon, and I was working on some follow-up questions when I discovered that Alan had answered most of them in a http://pluto.jhuapl.edu/overview/piPerspective.php?page=piPerspective_05_09_2012.



I'm curious why NH won't last as long as the Voyagers. Of course it has a substantially smaller RTG, but the decay rate should be roughly comparable. Perhaps NH's spacecraft housekeeping takes proportionately more of its power than is the case for the Voyagers?

Edit: I've belatedly realized that "last as long" and "get as far" are different questions, because the Voyagers are traveling faster than New Horizons. But Alan indicates that "New Horizons has the power and technical capabilities fly late into the 2020s or even into the 2030s if its health remains good," and I still wonder why the shorter life-span.

Posted by: Alan Stern Sep 6 2012, 02:45 PM

New Horizons has 1 RTG, not 2 as the Voyagers do.Also, some will recall we got shorted on Pu-238 owing to two closures of LANL during the mission build-- we launched with 25 watts less power (read: 10+ years lifetime) than we originally hoped for. Double that with 2 RTGs and you have the basic answer to your question.

Posted by: Tom Tamlyn Sep 6 2012, 09:18 PM

OK, I finally get it (less margin), and I apologize for being dense. Thanks as always for taking the time to monitor this thread.

Posted by: Tom Tamlyn Sep 7 2012, 06:18 PM

As I was thinking about Alan’s answer, I remembered that the SwRI site for New Horizons has a comprehensive collection of freely downloadable technical papers written by scientist and engineer participants in the mission, found at http://www.boulder.swri.edu/pkb/, the kind of basic information that you have to scrounge for with most missions.

One paper, Fountain, et al., The New Horizons Spacecraft (02 Feb 2007) contains a four-page discussion of the NH power system. In particular, Figures 10 and 11 at p. 25 were particularly helpful to me in visualizing the relationship between the RTG’s initial power output and the mission’s lifespan.

 NH_power_chart.pdf ( 89.74K ) : 708



It’s immediately obvious how an extra 25 watts of initial power would have translated into 10 more years of fully operational lifespan.

TTT (when I figure out how to convert the 90k attachment into an inline image or thumbnail, I'll do it)

Posted by: stevesliva Sep 7 2012, 08:09 PM

I suppose it's worth asking whether the instruments on NH measure anything that the Voyagers and IBEX don't. Certainly another in-situ measurement is good, but I wonder, in terms of measuring empty space, what's new?

Posted by: imipak Sep 7 2012, 08:15 PM

The NH power charts Tom posted, inline:

o`

Posted by: Tom Tamlyn Sep 7 2012, 09:22 PM

Thanks imipak! Looks great, just what I wanted.

How did you do that? I tried copying the attachment url into the "insert image" tool, but I got an error message about dynamic links. I know zippo about html ....

Posted by: dilo Sep 8 2012, 01:14 PM

Based on these plots, they should be able to make correction maneuvers and science activities until early 2024 (59 au) and downlink data until 2029 (74 au).
Moreover, if mission extension will be financed, I'am pretty confident they will be able to further improve these margins by optimizing operations (as done on Voyager)

Posted by: hendric Sep 9 2012, 02:04 AM

Alan,
Do those power margins account for shutting down unnecessary systems as NH ages? Or is the technology good enough now (I'm an embedded engineer myself) that a low-power mode for an instrument is essentially near-zero power?

Posted by: Alan Stern Sep 9 2012, 09:18 AM

The figures in Glen Fountain's paper do not include measures we can take to extend mission duration, which we now estimate will take us to the mid-late 2030s. However, those measures do not generally include low power instrument modes, as most NH instruments do not have them.

Posted by: Paolo Sep 9 2012, 12:51 PM

this in interesting: the search for candidate KBOs continues to provide some "collateral" discoveries
http://www.abstractsonline.com/plan/ViewAbstract.aspx?mID=2924&sKey=00e3ee1c-d964-48e9-b883-919771391381&cKey=195d9f73-7764-40eb-8fed-df751407bde7&mKey={C752C15A-58ED-4FA6-9B4A-725245476867}
and it may also receive some distant (180 million km) observations

Posted by: morganism Sep 10 2012, 11:36 PM

Am a big fan of the KBO post encounter, and threw in some time at Ice Hunters, but would trade it all for a trajectory change to get more info on Uranus or Neptune.

That red trojan looks interesting tho, and nearly a 30 deg inclination is crazy!

Am specifically interested if there are any flux tube re-connections out there.

OPAG doesn't look like they will be chosen in time to still have any specialty scientists still around to study an ice giant.....

Posted by: Tom Tamlyn Sep 11 2012, 06:13 AM

<cough>

I've attached a diagram showing the positions of the outer planets at the time of New Horizon's Pluto encounter, together with a cone indicating the outer limits of NH's ability to change course after the encounter. The diagram is figure 14 from Guo and Farquhar, New Horizons Mission Design (2007), available at http://www.boulder.swri.edu/pkb/.
 nh.cone.pdf ( 62.03K ) : 785
*
Keeping in mind the narrowness of the cone, the positions on the diagram of Uranus and Neptune, and of course the fact that Uranus and Neptune will continue to march, "rank on rank," as members of "[t]he army of unalterable law" ** further counterclockwise from the Pluto rendezvous point ... what kind of trajectory change are you talking about?

TTT

_______
* I've looked at BB Code Help, I've searched the forum, I've googled (per http://www.unmannedspaceflight.com/index.php?s=&showtopic=6029&view=findpost&p=140989), and I've looked at page source, but haven't figured out how to post an inline image. I'm sure it's only a few characters of code with a simple syntax, but I'm not able to intuit what those words and syntax are. To avoid threadjack. I'll start a thread in EVA/Chit Chat or EVA/Image Processing Techniques.

** Apologies to George Meredith.

Posted by: TheAnt Sep 12 2012, 06:30 PM

I guess that would have to be the kind of trajectory change that involved the reverse gear.

Posted by: udolein Sep 20 2012, 06:09 PM

Candidate for post-Pluto encounter - Plutino 15810:

http://o.canada.com/2012/09/18/a-possible-post-pluto-flyby-target-for-nasas-new-horizons-spacecraft/

Cheers, Udo

Posted by: centsworth_II Sep 20 2012, 07:21 PM

The amateur search for post Pluto targets is no longer hosted by Zooniverse as mentioned in both the linked article and the Planetary Society blog post (linked in the article). It is now at http://cosmoquest.org/ as Ice Investigators.

In any case there are not currently any images available to search in. I guess Pamela Gay has her work cut out getting word out about Cosmoquest.

Posted by: brellis Oct 10 2012, 11:38 PM

Looks like there is a pre-Pluto target http://www.planetary.org/blogs/guest-blogs/20121009-parker-neptune-trojan-ice-hunters.html

Posted by: Explorer1 Oct 11 2012, 02:06 AM

Looks like the actual photos won't be any better then that asteroid a few years ago;, but I'm sure the team will take what they can get. Not like a detour is possibly anyway...

Posted by: centsworth_II Oct 11 2012, 02:18 AM

I see at least one UMSF contributor there.

"Along with the New Horizons search team, the citizen scientists of Ice Hunters assisted in identifying 2011 HM102 in recovery images. The names of those that detected 2011 HM102 are listed below:
... http://www.unmannedspaceflight.com/index.php?s=&showtopic=7411&view=findpost&p=190993..."

Posted by: tdemko Oct 12 2012, 12:08 AM

My KBO L5 Neptune Trojan identifying skills seem to have been much better than my spherule mineralogy identifying skills.

http://www.minorplanetcenter.net/mpec/K12/K12T05.html

Posted by: centsworth_II Apr 16 2013, 02:09 AM

And now your name appears, along with other Ice Hunters, in appendix A of http://www.dtm.ciw.edu/users/sheppard/pub/Parker2013.pdf (PDF)

Posted by: tdemko May 7 2013, 04:33 PM

It's nice to know that I contributed, in some small fashion, to the exploration of the solar system and beyond. The Ice Hunters project was very well designed, both from a contributor and end-user standpoint, and I hope that there are other similar opportunities for direct involvment in missions and data analysis. I hope that there will be imaging opportunites for New Horizons to view L5 Neptune Trojan 2011 HM102...it will be like connecting with someone you've only had a fleeting glimpse of, but now have the chance to learn much more!

Posted by: Paolo May 29 2014, 08:10 AM

today on arXiv: http://arxiv.org/abs/1405.7181

Posted by: Explorer1 Jun 16 2014, 06:07 PM

http://hubblesite.org/newscenter/archive/releases/2014/29

Posted by: Floyd Jun 16 2014, 06:47 PM

Fantastic!

Posted by: Jaro_in_Montreal Jun 16 2014, 09:37 PM

" If the test observation identifies at least two KBOs of a specified brightness, it will demonstrate statistically that Hubble has a chance of finding an appropriate KBO for New Horizons to visit. At that point, an additional allotment of observing time will continue the search across a field of view roughly the angular size of the full Moon."

What are the chances of the test observation identifying at least two KBOs of a specified brightness ?

Good bet or not ?

Posted by: 0101Morpheus Jun 17 2014, 01:12 PM

It is a bet worth taking rather than not doing it at all.

Posted by: Mongo Jun 17 2014, 08:21 PM

If it were a choice between making 40 orbits worth of Hubble observations for identifying possible post-Pluto flybys, or having the Hubble simply sit idle for those 40 orbits, then it would be an obvious no-brainer. But in fact this means that 40 orbits of other observations will not be done. It's actually a fairly close decision, in my opinion.

Of course I hope that a suitable KBO is located, but New Horizons will have accomplished its initial mission goals even without flybys of additional post-Pluto objects.

Posted by: Jaro_in_Montreal Jun 17 2014, 09:05 PM

Thanks to Emily Lakdawalla for nailing this down ! ....much appreciated !

http://www.planetary.org/blogs/emily-lakdawalla/2014/06170922-hubble-to-the-rescue.html

Posted by: Fran Ontanaya Jun 17 2014, 09:28 PM

I wonder if aerobraking at Pluto would even be possible as a last ditch effort to get within the dV range of the closest one.

Posted by: elakdawalla Jun 17 2014, 09:46 PM

Jaro: Glad to be of service

Fran: Definitely not. They are traveling past Pluto at Charon's orbital distance for both safety and science reasons.

Posted by: remcook Jun 18 2014, 12:01 PM

That looks like it was a very well-written proposal as well. Fingers crossed in the next few weeks then. It will be an exciting next few years in any case.

Posted by: john_s Jul 1 2014, 07:09 PM

Just to let everyone know that we have found the required 2 faint KBOs in our pilot HST search program, and have been authorized to continue to the full 160-orbit Hubble search. We are all quite happy around here .

http://hubblesite.org/newscenter/archive/releases/2014/35/

John

Posted by: Mongo Jul 1 2014, 07:21 PM

Excellent news! Given the detection statistics so far, and NH's available post-Pluto delta V, is there an estimate of how many KBOs by diameter should be within its reach, assuming average luck?

Posted by: ngunn Jul 1 2014, 08:31 PM

I bet. Two is very low number statistics so this represents a dangerous moment passed, but not really a guarantee of success with the full search. Now it's less about luck and more about what's out there. Here's hoping . .

Posted by: Vultur Jul 2 2014, 02:11 AM

That's great! I hope something within New Horizons' delta-v range shows up (or even multiple objects to choose from?)

EDIT: When will the full search be completed?

Posted by: punkboi Jul 2 2014, 03:02 AM

The full Hubble search should be completed in August

Posted by: nprev Jul 2 2014, 03:06 AM

John, congratulations to you, Alan, and the team. We knew you'd do it, but it sure is a relief to have targets in sight!

Posted by: Bjorn Jonsson Jul 2 2014, 11:43 AM

Awesome news - congratulations.

Posted by: algorithm Jul 2 2014, 05:48 PM

Agreed, fantastic news for what could be an even more rewarding voyage. In my line of work it's the three Ps', preparation, preparation, preparation, this would apply here also, but with perseverance, perseverance, perseverance, again, well done and really looking forward to this one, especially perhaps some of the images to come down!

Posted by: Jaro_in_Montreal Jul 2 2014, 07:33 PM

My thoughts exactly.

Fabulous news nevertheless.

Best wishes on the full-scope search ! (....keep us posted pls!)

Posted by: Paolo Mar 17 2015, 08:28 PM

so, the two candidate KBOs now have preliminary designations courtesy of the Minor Planet Center: PT1 is now known as 2014 MU69 and PT3 is 2014 PN70.
you can find orbital elements in this http://www.minorplanetcenter.net/mpec/K15/K15E51.html. search for K14M69U and K14P70N. both are low inclination and small eccentricity "cold" KBOs orbiting near 44 AUs. I am surprised by the small eccentricity of 2014 MU69: only 0.05

Posted by: Holder of the Two Leashes Jul 15 2015, 03:13 AM

Now that New Horizons appears to be safely beyond Pluto, we can begin anticipating the KBO encounter in 2019 with more confidence. The preferred target right now seems to be http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2014+MU69&orb=1,
although http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2014+PN70&orb=1 is still in the running. The latter is somewhat larger (or at least brighter) but will require more fuel. I read in an interview with Alan Stern that he mentioned a decision as to which one will be made in August.

Posted by: kap Jul 15 2015, 04:34 AM

Do you have any idea why the fuel usage is a concern? Is there any possibility of additional targets after the second encounter?

-kap

Posted by: Holder of the Two Leashes Jul 15 2015, 05:17 AM

Probably not so much the hope of a second KBO as simple caution at this point, although there might be some people hoping and still holding out for a second iceball. Just a guess, but I think the main concern is that targeting 2014 PN70 would leave NH with substantially less remaining fuel reserve. With four years to go they may want a better margin for just-in-case whatever. This would be a good question for someone actually on the team.

Posted by: Explorer1 Jul 15 2015, 05:58 AM

I recall from other missions that it is standard to just 'burn to depletion' and empty the fuel tanks to get good estimates for how much was in them, as an engineering exercise. Maybe after a flyby it would be best to use the rest to just get as close as possible to a second KBO? Obviously this is early speculation...

Posted by: MahFL Jul 15 2015, 11:26 AM

They want to operate the spacecraft for years and years after the KBO encounter, you need thruster fuel to do that, so that is why thruster fuel is always a concern.

Posted by: abalone Jul 15 2015, 11:32 AM

Just out of interest, what delta V do each of the candidates need compared to the delta V still in the tank? or What is NH's the cone of reachability and how close is each to the edge?

Have any followup observations been done or are planed by Hubble to identify any further targets now that the search area is smaller?

Posted by: Paolo Jul 15 2015, 12:41 PM

this paper should answer most of your questions:
http://www.hou.usra.edu/meetings/lpsc2015/pdf/1301.pdf

Posted by: abalone Jul 15 2015, 12:59 PM

Thanx

Posted by: climber Jul 15 2015, 06:50 PM

Another answer, 100m delta V: https://twitter.com/jeff_foust/status/621381270640197637

Posted by: abalone Jul 16 2015, 12:46 PM

That's a bit confusing 100m/s, what does that include?

Posted by: Floyd Jul 16 2015, 02:25 PM

From the paper Paolo cited, the NH has enough propellant to change the velocity by up to 130 m/s. Target 1 would require a deltaV of about 60 m/s and target 3 would require about 120 m/s. This is a very small nudge to a craft traveling at ~30,800 mph or ~50,000 kph=13,889 m/s. Therefore the cone is only about 0.54 degrees at a max 130 m/s

Posted by: Greenish Jul 17 2015, 06:05 PM

What's unsettling about the cone-angle number of ~0.5 degrees is that according to JPL Horizons ephemeris (not New Horizons ) the long axis of the 3-sigma positional error ellipse for 2014 MU69, viewed from Pluto is currently +/-2400 arcsec (0.67 deg) and for 2014 PN70 is +/-6900 arcsec (1.9 deg). So I'd suspect they want to save some fuel and get more data between now & then -- even if they shoot for the best known position they could be way off! And at visual magnitudes of ~22 from Pluto now (24-25 from Earth) it will be a long time before it's visible to New Horizons cameras for any sort of optical nav.

Maybe there's a better source they're using, with positions not included in the MPC database, or these estimates are excessively conservative (perhaps not accounting for Hubble precision). And if re-observed (would it have to be by Hubble?) the improvement should be significant due to the greater time baseline. I wouldn't be surprised if this is one of the reasons they would wait until much later this year to execute the maneuver.

Posted by: djellison Jul 17 2015, 07:21 PM

Clearly, given the accuracy and error bars of the PDF oft cited in this thread.

Posted by: Holder of the Two Leashes Jul 19 2015, 04:27 AM

It appears they have already completed a program of follow up observations by the Hubble of the two potential targets. The program was listed on the Hubble site as http://www.stsci.edu/hst/phase2-public/14053.pro and given the status of "completed". The observations were made in May and earlier this month. So yes, the NH team already has more accurate orbits than are currently listed on official minor planet sites (MPC and JPL).

Posted by: Greenish Jul 20 2015, 06:25 PM

Yes, that inconsistency was what prompted me to look at the ephemeris on Horizons. Perhaps I should have said "presumably" rather than maybe.

In any case, thanks Holder for the info on the followups - good to know the observations are already "in the bag."

Posted by: Holder of the Two Leashes Aug 12 2015, 06:02 PM

New article on Spaceflight Now ...

http://spaceflightnow.com/2015/08/11/scientists-plan-for-new-horizons-probes-second-act/

Posted by: Nafnlaus Aug 18 2015, 05:26 PM

Less than half of the remaining delta-V for target 1? Perhaps I missed it, but has any consideration been given to the possibility of two subsequent flybys, should a target be found in the post-target-1 cone? One would assume that any such flyby possibility would be many years off - does anyone know how long NH's RTG is expected to be able to provide enough power to transmit? I assume the lowest possible power consumption mode it could operate in would be like the current spin-stabilized 2-TWTA transmission mode, but only with one TWTA active.

Posted by: hendric Aug 18 2015, 07:09 PM

Yes, the original stretch goal was two KBOs, but the difficulty of searching for KBOs limited them to just the ones they found. The original ground search didn't yield any viable targets, they had to request Hubble time and were lucky to find two. It's possible they could find another, but I doubt they would be given more Hubble time. It doesn't go to waste though, as I understand it the fuel is required for pointing so any extra fuel means a longer extended mission. I think the fuel is the limiting factor, not the RTG. Might be possible at End of Mission to leave NH spinning so it can still occasionally communicate with Earth, but I don't know how long that would be effective before it moved enough Earth would be out of its cone. Although, it has such a large data recorder, maybe the mission could set it up to target a direction to Earth X years past end-of-mission? Point it to where Earth will be in 20 years, set up an autonomous mode to store data, start spinning, and hope for the best.

Posted by: JRehling Aug 19 2015, 03:56 PM

Right now, I feel like there's one key observation to make, given what was seen at Pluto, and that's whether the surfaces of tiny icy bodies are as ancient as those of tiny rocky bodies. Since we saw that Pluto and Charon (which aren't tiny) seem to have had thermal evolution going on much later than expected, it would be good to get one observation at the smaller end of the size spectrum.

Both of the leading candidates are well smaller than Mimas, so if we see anything but an ancient surface, that'll be a bombshell.

Posted by: nprev Aug 19 2015, 11:52 PM

"Smaller" is an understatement; the upper diameter estimate for both is 55 km. Can't see any possibility at all that we'll see anything but an ancient, battered surface on either.

Posted by: jasedm Aug 20 2015, 09:41 AM

I would imagine the camera targeting sequences will be one heck of a challenge in order to actually see any surface features on a body this small and whose orbital parameters are all but unknown at this stage.

LORRI will be what, six months out before it can actually track the chosen KBO?

Add to this the speed of NH as well. Presumably to get any surface detail, the close approach distance would have to be sub-10,000km with the risk of serious blurring in any images.

I wonder if the team will be looking at attempting the 'skeet-shooting' technique used by Cassini at Enceladus?

Posted by: hendric Aug 20 2015, 03:13 PM

Well, NH is slowing down the further it goes, but probably not enough to compensate for the reduced sunlight available. I don't expect the pictures to be any worse than Charon. A similar closest distance as at Pluto gets us pictures a ~125 pixels across, with ~400m/pixel resolution, which should be good for learning some morphology.

My bet is that we will be surprised at the lack of craters. If these are primordial bodies, they grew by accreting nearby materials at a slow speed, like the ~basketball sized bodies seen in the walls of Rosetta's comet. The surface at a small scale with be lumpy/hummocky, with a couple of larger "mountain" areas where they gathered another small planetoid. I'm thinking something like Calypso/Helene, but not as smooth as Telesto or Methone.

Posted by: Nafnlaus Aug 20 2015, 04:57 PM

The issue is not about how they formed, but what's been happening to them since. We have every reason to think that there should have been plenty of collisions since accretion.

As far as energy goes, there's not only potential energy imparting from impacts, but also from having their orbits changed, either rapidly or slowly with time. Obviously there should be no relevant internal heat for such a small body.

If a lot of the topography we see on Pluto and Charon is due to subsidence after nitrogen loss, then we might expect to see the same from smaller KBOs, albeit I would certainly expect any such processes to have long ago finished, and the much lower gravity would limit the ability for the body to become compacted (they're not in hydrostatic equilibrium). On the other hand, any topography coming from thermal expansion and contraction as the object grows nearer and further from the sun during its orbit would still happen on a smaller body today.

Even without having visited them, we know that there's a good bit of variety in KBOs, at least in terms of color and albedo. The presence or absence of moons may also lead to unique properties. And also, depending on where their orbits are, this may change the boiling/melting points, viscosities, etc of various substances on them.

So while the Pluto-Charon system was clearly the star of the show, I'm still pretty excited to see what any future flyby - or flybies, plural - might reveal.

Posted by: Habukaz Aug 28 2015, 07:24 PM

Target is selected: 2014 MU69 aka PT1.

http://www.nasa.gov/feature/nasa-s-new-horizons-team-selects-potential-kuiper-belt-flyby-target

Posted by: Gennady Ionov Aug 29 2015, 05:09 PM

I added 2014 MU69 target into a set of evaluated parameters on my page
http://swz.narod.ru/_Pluto/_NewHorizonsEng.html