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KBO encounters
JRehling
post Jul 28 2017, 09:08 PM
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Tom, the occultation / photometry paradigm permits almost unlimited resolution, in principle. This is how Kepler could determine the radii of planets over 5,000 light years away, Pluto and Charon were mapped during a series of mutual transits, and many asteroids have had their size and shape measured from Earth. The opportunities are, unfortunately, very limited and not readily of our choosing. It's a lucky coincidence that NH is barreling towards the Milky Way, which enormously increases the probability of occultations. If we'd sent a flyby past Pluto a few decades earlier/later, this would not have been the case.

Just last night, I completed a pair of images of Iapetus showing the steep difference in its brightness now versus 40 days ago. It'd be a tall order for an earthbound telescope to resolve Iapetus' surface features, but noting the difference in brightness was performed by Giovanni Cassini in 1705!

Absolutely no earthbound telescope built (or even conceived) could resolve a KBO at kilometer scale, but this occultation method would work even if the target were a thousand AU away.
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hendric
post Jul 28 2017, 09:21 PM
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If I did my maths right, to get 1km resolution at 30 AU requires a 716km aperture at 500nm wavelength. At 20cm (radio waves), it would take ~286,000km, so hypothetically possible if done with synthetic aperture using a lunar radio telescope. smile.gif

It would be amazing if we got a Dactyl like moon, or a contact binary. My money though is on a fairly smooth surface made up of 2-3m sized objects stuck together, similar to what we saw on 67P. Of course, those won't be resolved by NH.


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Holder of the Tw...
post Jul 28 2017, 10:10 PM
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QUOTE (hendric @ Jul 28 2017, 03:21 PM) *
If I did my maths right, to get 1km resolution at 30 AU requires a 716km aperture at 500nm wavelength


Not quite so large as that. The 2.4 meter Hubble can already resolve Pluto, seeing features around 1000km big on that body. To resolve to 1 km you need a mirror about 1000 times bigger. So two to three kilometers.

Which is bigger than anything I've got.
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JRehling
post Jul 29 2017, 01:22 AM
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Note that HST's highest resolution photos of Pluto were taken in ultraviolet light – not a coincidence! Shorter wavelengths have smaller diffraction patterns and allow higher resolution, all other things being equal. In visible light, resolution would be about 25% worse.

I believe the construction of HST's Pluto albedo maps involved combining multiple images with a very well known shape model – Pluto had to be a sphere – which is a luxury one wouldn't have in trying to resolve the shape of a tiny body. So those maps had a better resolution than any one image of an unknown object could ever be.
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hendric
post Jul 29 2017, 01:31 PM
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Hubble's albedo maps used the mutual eclipses between Pluto and Charon to determine how much the system brightness dropped as each body was covered up by the other. With advanced geometry and lots of computer time, scientists were able to make a best-guess as to the actual surface. Pretty good job, IMO!


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stevesliva
post Aug 3 2017, 09:11 PM
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The target is binary, or oblong:
http://pluto.jhuapl.edu/News-Center/News-A...p?page=20170803
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Explorer1
post Aug 4 2017, 01:38 AM
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Gosh! I briefly thought this might be the case with the initial negative occultation result (i.e. the slimmer axis caused it to miss the star). Looks like we're getting two for the price of one!
Talk about good luck! (unless binaries are super common....)
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climber
post Aug 4 2017, 04:36 PM
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Naming contest's gona be more challenging rolleyes.gif


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alan
post Aug 9 2017, 04:56 PM
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QUOTE
Alex Parker‏ @Alex_Parker

To those curious as to what the 2014 MU69 occultation data looked like, see @AlanStern's new PI's Perspective post:
http://pluto.jhuapl.edu/News-Center/PI-Per...tive_08_08_2017


https://twitter.com/Alex_Parker/status/895033405263446016

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Roby72
post Dec 6 2017, 10:36 PM
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A new PI's Perspective:

http://pluto.jhuapl.edu/News-Center/PI-Per...tive_12_06_2017
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Explorer1
post Dec 12 2017, 08:03 PM
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Unconfirmed for now, but there might be a moon (!!!) https://www.nasa.gov/feature/does-new-horiz...get-have-a-moon

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tasp
post Dec 17 2017, 12:46 AM
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Binary object with a moon ?

That's 3 objects to study. What a bonus !!!

Amazing if confirmed. GJ everyone involved!
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Explorer1
post Jan 24 2018, 07:07 PM
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Not so fast! Could be just a glitch... http://www.planetary.org/blogs/emily-lakda...r-2014mu69.html
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bobik
post Jan 25 2018, 08:24 AM
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http://www.thespacereview.com/article/3398/1
QUOTE
There is one more occultation by 2014 MU69 that could be observed prior to the flyby, on August 4. The occultation’s narrow path takes it across parts of Colombia and Venezuela, making landfall again near Dakar, Senegal, and extending across West Africa. “It’s not the best spot in the world for us to be doing this, but it’s not hopeless, either,” Buie said. There are active discussions with observers in Colombia and Senegal about trying to observe it, he noted. Attempting to observe both the main object and its apparent moon requires a large number of telescopes, densely arrayed. “Getting both is going to be a really big stretch, but I think it’s worth giving it a shot.”

Is there a website which details the August 4 occultation event? I found nothing. Maybe not the best strategy to get as many as possible telescopes on the spot.
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dtolman
post Feb 13 2018, 04:47 PM
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Surprised no one has posted this already! New Horizons Made history (again) on its way to its Kuiper Belt Object encounter on New Years Day - newly released pictures are both the furthest pictures ever taken by a spacecraft (beating the Voyager 2 Pale Blue Dot images in distance from Earth), and the closest pictures ever made of a KBO.

Here are a few of the images released - KBOs 2012 HZ84 (left) and 2012 HE85 (right) as seen by the LORRI camera at 40.9 AUs from the Earth:


These pictures were taken back in December before hibernation - spacecraft is scheduled to become active again in June, so we should get images that break both these records soon after.

The detail is pretty impressive - as our most distant telescope/camera from Earth - LORRI could make a lot of discoveries even without the close encounter on New Years Day 2019.
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