KBO encounters Options

[Greg Hullender]

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.

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

[nprev]

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.

[john_s]

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

[nprev]

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

[ngunn]

Ditto from me. Much appreciated.

[Greg Hullender]

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

[tasp]

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

Does this impact KBO search?

[john_s]

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

[hendric]

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-...eaking-coolant/

[tasp]

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?)

[Gsnorgathon]

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...

[centsworth_II]

...We are still working through the 2004/2005 preliminary search data...

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.)

[john_s]

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

[centsworth_II]

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.

[Greg Hullender]

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