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 ?
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.
...our definition of celestial vermin seems to be shifting, doesn't it? Bloody core stars...
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...
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. :-)
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?
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.
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).
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.
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?).
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?
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.
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!!!
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.
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 :
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.
Couldn't blame them if they didn't do anything. Not a whole lot you could do at 2.76 AU.
The first post in this thread says the search would start in 2010 - has it started yet, or will it be later this year?
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.
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."
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.
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.
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.
If we find it, can we name it?! I always thought that "Astro0's Orb" had a nice ring to it!
THAT is a rockin' piece of citizen science outreach, John! Very much looking forward to it!
That's great news, can't wait to participate in the search for targets!
Look for another release in a few weeks, describing how you can help us sift through all those images.
It's in beta, still several weeks from launch.
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.
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
To try out the site as a beta tester, go to:
The tutorial is here:
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
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.
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!
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!
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.
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.
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?
Oh dear I can't use IE7, which is on my work PC, bummer.
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.
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.
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!
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.
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.
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)
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.
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?
Thanks for these examples, Richard and all!
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.
I thought this was a thing of beauty, as far as finding transients in dense starfields go.
Okay, I'll play: I see two, possibly binary.
This particular processing method seems to make them stand out, if I was correct.
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?
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, 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!
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.)
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.
Sure enough; thanks, T! (Der...there's was even a warning about this had I scrolled down the screen a bit...)
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.
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! >
It's very addictive
Yeah, ain't it? I'm over something like 2100 images now.
Okay, now @ 2257 images with a detection rate of 18% (incl. asteroids). How does this compare with everyone else's stats so far?
18%? And you haven't shown us a *single* image yet. That's disgraceful! Don't you know how important sharing pictures is?
<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.)
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:
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
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
...and dig THIS behemoth. Perhaps a TNO rather than a KBO? Dunno.
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!
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!
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...
I'm thinkin' maybe just this one time, Nick, 'cause I ain't gonna live forever...let's take full advantage of it!!!
OK I'm addicted now.
Just finished my first 200 (as "cents"). Almost relaxing. WAY easier than the Stardust particle search which was too taxing on me.
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)
Does someone want to show me some distinct examples of variable stars verses KBOs? I think my hit-rate is too high.
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!
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.
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...
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
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!
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.
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).
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.
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?
Up to 2500 views now and this is easily the most artistic (and one of the least scientifically useful) images I have seen.
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...
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!
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
(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.
Okay, thanks maschnitz.
Time to find something else to do tonight.
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.
A near miss!
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.
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.
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.
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.
I agree with all your rules save #3, Greg; I think that the faint ones are by far the most likely new discoveries.
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.
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!
Thanks for the thorough response, John. "Dammit, Jim"...
Ditto from me. Much appreciated.
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.) :-)
I heard the Subaru telescope was damaged by a coolant leak.
Does this impact KBO search?
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.
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.
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?)
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...
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.
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.
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.
Even some very faint objects aren't getting past Icehunters' scrutiny.
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.
I agree with #5.
I agree too, especially on last 3 points!
I aqree with #5 as well; had that happen several times, and it just kills me!!!
NOTE: This post is only for IceHunters or people interested in IceHunters. Perhaps we should start a new thread?
In response to a request by the science team, Icehunters are really getting serious about finding faint objects!
Yes, and now it makes sense to use the contrast button. It really makes the faint objects pop!
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!).
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 )
I'm curious, though, for the image pairs being subtracted what is the range of motion for an actual KBO between the images?
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...
Thanks, Dr. Spencer!
So maybe I have a better chance with my second-most-favorite guess at a real KBO:
That gives a pair with nice equal-looking-magnitude with ~36 pixel separation.
...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?
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 ).
Icehunters now has many of the reviewed objects identified as variable stars.
Some are now marked as KBO - confirmed including a couple of mine
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.
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.
I was wonder how many KBO's potential targets to New Horizons, and make this grafic.
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!
I got one confirmed out of 3568 images, and six marked as "Likely KBO/Variable Star".
With a database of variable stars, will you be able to pre-mark the known variables in future images?
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 :
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,
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.
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.
Hero! Total hero! Nicely done
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)
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?
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!
I got me a KBO! I'm pretty surprised actually, I only had ~3k images searched.
I shall keep it, and pet it, and name it George!
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 :-)
I had 1441 images. Looks like statistically (from some stats by a forum user), you could reasonably expect 1 in 2000.
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!
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.
Looks like I got one too! First to spot it (by 38 seconds!). IH-267996.
...but will it get a visit?
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!
OK, thanx for that.
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!
4 for me, one I missed being the first to spot by 3 seconds
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.
^ 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.
Just noticed the following in the IceHunters forum.
I used the firstname.lastname@example.org 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.
Will these get minor planet temporary designations?
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.
Anyone else getting a real Star Wars vibe from those sound effects and visuals?
Just need a lost TIE fighter now...
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:
posted a few minutes ago on NewHorizons2015 twitter:
Oh, that would be nice! Looking forward to the details.
Looking forward to seeing what this is...distant flyby can mean a lot of things.
"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!
Just light curves? Or something more like resolving satellites?
probably characterization of a KBO at phase angles impossible from Earth
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.
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.
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, 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?
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.
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.
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.
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.
OK, I finally get it (less margin), and I apologize for being dense. Thanks as always for taking the time to monitor this thread.
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 ) : 216
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)
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?
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 ....
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)
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?
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.
this in interesting: the search for candidate KBOs continues to provide some "collateral" discoveries
and it may also receive some distant (180 million km) observations
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.....
Candidate for post-Pluto encounter - Plutino 15810:
Looks like there is a pre-Pluto target http://www.planetary.org/blogs/guest-blogs/20121009-parker-neptune-trojan-ice-hunters.html
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...
KBO L5 Neptune Trojan identifying skills seem to have been much better than my spherule mineralogy identifying skills.
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!
today on arXiv: http://arxiv.org/abs/1405.7181
" 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 ?
It is a bet worth taking rather than not doing it at all.
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.
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.
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.
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 .
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?
The full Hubble search should be completed in August
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!
Awesome news - congratulations.
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!
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
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.
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.
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...
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?
Another answer, 100m delta V: https://twitter.com/jeff_foust/status/621381270640197637
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
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.
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).
New article on Spaceflight Now ...
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.
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.
"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.
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?
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.
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.
Target is selected: 2014 MU69 aka PT1.
I added 2014 MU69 target into a set of evaluated parameters on my page
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