KBO encounters Options

[scalbers]

But there are issues:
The normal imaging cadence will exclude a region ~1000 square degrees around the galactic center; the high stellar density and high luminance leads to saturation of the sensors and confusion of the automated system. (Even the motion of the brightest asteroids will not be catalogued, due to saturation issues.)
Exposures in this region will be less frequent and with fewer filter bands.

There are also potential issues with the way that the LSST (and the MPC) will track and report on "moving objects": they plan to identify things that move from night to night, but a small distant KBO may appear to not move enough in 24 hours (to shift position relative to background stars) to be detected as "moving" at the resolution of the LSST optics.
Doing frequent searches over multiple nights becomes computationally very expensive.

But the main problem is that it probably won't start science observations until 2023 at the earliest.

Yes this could be a challenge, though I wonder if even the relatively less frequent imaging near the galactic center would still be more frequent than other surveys. Since the raw LSST data are planned to be publicly available, it seems that anyone could apply customized search algorithms that might do better than the standard image search methods. Over the next 5-10 years will NH and KBOs on intersecting trajectories continue to be in very dense star regions, or in any dark nebulae of opportunity? It also seems like there could be some undiscovered KBOs with magnitudes in the 20s in the general NH part of the sky.

The 24 hr motion due to parallax of a KBO at 50AU should be around 35" and thus easy to identify distant objects if a search can be done from night to night. The component from orbital motion is smaller, around 5", so the angular motion vector would take more time to pin down accurately. Here is some info on LSST search strategy and an overall summary of some past, ongoing, and future KBO searches. It looks like the background star density is now decreasing judging from this summary as NH has been moving past the main part of the Milky Way.

Note that close up current locations of NH and UT are here.

[Guest_Steve5304_*]

praying for an eris like object 5-6 years out gets discovered

[Explorer1]

I think the chances are very low of anything a few hundred km across. Even against the milky way as background, something that size would have popped up easily long ago.

[HSchirmer]

praying for an eris like object 5-6 years out gets discovered

Well, if there IS something like that, it would be worth checking out-

Because it would be an interesting combination of coal-dark AND large.

That's one of the twists for KBO's, we've found the A-list (large + bright), now we're left with the B-list small+bright or C-list (large + dark) to find during the next round of observations.

Actually, the next KBO should likely be from the C-list (large + dark) because that SHOULD show up nicely in the next generation of orbital IR telescopes...

[nprev]

A very large object like that would have doubtless been discovered a few years back during the initial KBO search since that was restricted to feasible targets for NH post-Pluto. If there is one along its future possible trajectories it's WAY out there and the flight time would almost certainly exceed the useful lifetime of the spacecraft's RTGs.

[Y Bar Ranch]

Too bad there's no sort of "flash" mechanism going off in the outer hinterlands of the solar system that could momentarily illuminate KBO objects.

[HSchirmer]

Too bad there's no sort of "flash" mechanism going off in the outer hinterlands of the solar system that could momentarily illuminate KBO objects.

Well, sorta the opposite, we're more likely to detect occultations, where KBOs momentarily block the illumination of stars. Since the KBOs we're interested in are current moving against the bright background of the milky way, it's probably easier to detect the drop in starlight in comparison to the light reflected by the KBO.

[scalbers]

Maybe we need a rather nearby supernova to provide the flash? Unsure though if a potential one like Betelgeuse would be bright enough.

[fredk]

Interesting question. At 50 AU the sun appears roughly 8.5 magnitudes fainter than it does from Earth, so around -18. So to have significant extra illumination from a SN, the SN would need to be at least -18th magnitude. The brightest recorded in history was something like -7.5 (SN 1006). So you'd need a SN roughly 10 magnitudes brighter than SN 1006, so one roughly 100 times closer (and hence ~10^6 times less likely). SN 1006 was at 7200 ly, so we'd need one at least as close as around 70 ly. At something like 10 SNe/year in our galaxy, we'd have to wait a very, very, very long time...

[Explorer1]

I think the effects of a supernova on Earth's biosphere at that range probably outweighs the scientific return of illuminating KBOs, IMHO....

[Guest_Steve5304_*]

Maybe we need a rather nearby supernova to provide the flash? Unsure though if a potential one like Betelgeuse would be bright enough.

Well something like that is very unlikely to happen.


We may have reached our observation limitations....unless a large Ceres size body exists out that far with a degree or two of NH path, I just don't see it happening.

[HSchirmer]

Maybe we need a rather nearby supernova to provide the flash?
Unsure though if a potential one like Betelgeuse would be bright enough.

-Flash-of-inspiration- We don't need a supernova. We need to reverse our thinking:
How about using the biggest dish on New Horizons, the high gain antenna, like radar?

NH can detect a-millionth-of-a-billionth-of-a-watt of radio waves with the high gain radio antenna.
Turn NH forward and use the spin stabilized high gain antenna to listen for KBOs using radar pings.
NH could broadcast radio pings at around 12 watts.
DSS-43 in Canberra could broadcast radio pings at 400 kW (IIRC, nobody has ever tried it at full power).
Arecibo could broadcast radio pings at around 1 million watts.

Using the low gain antenna, order New Horizons to turn the high gain antenna FORWARD in spin-stabilized mode.
Turn the volume on Arecibo and the Canberra 70-meter scopes up to 110% and blast out a ping aimed AHEAD of New Horizons. Have NH listen for reflected pings with the high gain antenna - the only thing out there that could reflect a 1 km radio wave is a nearby KBO that is bigger than 1km. (might need to use some Cassini/Huygens doppler shifting magic to differentiate between red-shifted-outbound radio signals and blue-shifted-reflected-incoming radio signals)

If you detect a ping, then start slewing the spin axis during the pings so that the high gain dish samples a point, then a small circle, then wider circles, and track which azimuth offset (circle size) corresponds to the biggest increase in reflected radio waves.
Then a pattern of timed pings could determine where along the circle the reflection is the strongest, i.e. that the KBO is located at, for example 4-o-clock on that circle.

Follow up with a spin-stabilized search with a sweep of x-band frequencies to determine likely KBO size.

-- All of this AFTER NH is done downloading the Ultima Thule data, of course.

[elakdawalla]

OK, folks, let's limit the speculation and noise in this thread please. Keep it to well-sourced information about New Horizons' actual KBO encounter and observation plans.

[HSchirmer]

-Flash-of-inspiration- We don't need a supernova. We need to reverse our thinking:
How about using the biggest dish on New Horizons, the high gain antenna, like radar?

NH can detect a-millionth-of-a-billionth-of-a-watt of radio waves with the high gain radio antenna.
Turn NH forward and use the spin stabilized high gain antenna to listen for KBOs using radar pings.
NH could broadcast radio pings at around 12 watts.
DSS-43 in Canberra could broadcast radio pings at 400 kW (IIRC, nobody has ever tried it at full power).
Arecibo could broadcast radio pings at around 1 million watts.

Using the low gain antenna, order New Horizons to turn the high gain antenna FORWARD in spin-stabilized mode.

Bump,
Found some discussions about using radar from -DSN- at Ultima Thule

For both trajectories, we chose the nominal close approach time to be 05:33 UT on 1 January 2019. The flyby date was selected to minimize propellant consumption. The flyby time on that date is about an hour earlier than the uncontrolled (minimal propellant usage) arrival time, to allow the spacecraft to receive uplink signals from both the NASA Canberra and Goldstone Deep Space Network (DSN) stations to attempt a bistatic radar measurement of MU69 shortly after closest approach.


Found some prior info about NH using at Pluto expecting to use radar from Arecibo and DSN to reflect off Pluto and be imaged by REX camera-
http://www.planetary.org/blogs/guest-blogs...tes-part-1.html
https://www.lpi.usra.edu/opag/meetings/sep2...tions/Stern.pdf

About 30 dB advantage for NH at Pluto using REX Details about NH and REX as page 73 of Advances in Bistatic Radar

Has anybody published any results based on NH using radar signals from DSN to study Pluto's atmosphere, or surface roughness?

[WTW]

Here is some info on LSST search strategy and an overall summary of some past, ongoing, and future KBO searches. It looks like the background star density is now decreasing judging from this summary as NH has been moving past the main part of the Milky Way.

Note that close up current locations of NH and UT are here.

A couple of notes of caution:
(1) The "overall summary" of "past, ongoing, and future KBO searches" linked to above is over 10 years old and badly out of date. The field has learned a lot in the last decade, both about the Kuiper Belt and about searching for KBOs.
See for example
http://iopscience.iop.org/article/10.1088/...-637X/782/2/100 (where the authors admit errors made in earlier analyses and "unexpected properties" of KBOs and the Kuiper Belt)
https://arxiv.org/pdf/1607.04895.pdf
and of course https://arxiv.org/abs/1805.02252

(2) The wonderful TheSkyNow.com web site apparently uses the GSC 2.3 sky atlas for the star background. The STScI Guide-Star Catalog II is a digital scan of the (film-based) Palomar POSS-II, or DPOSS; that catalog cuts off at a magnitude of about ~20.8 in the F filter ("red", centered at about 650nm) and ~19.5 in the near IR (centered at about 850 nm). Resolution of the original scanned images is about 1 arcsec per pixel, but astrometric accuracy is at about ~0.3 arcsec. It looks fantastic.
But given the limited dynamic range of typical computer displays, TheSkyNow is not really indicative of what a deeper, more sensitive digital survey "looks like" -- where things like saturation and blooming of CCDs become worse, due to longer exposure times, CCD thermal and read noise and shot noise become problematic, images of individual objects can fall into the boundaries between CCD cells, etc. etc.


My suggestion is that, if "citizen scientists" want to help find Kuiper Belt objects and their orbits for New Horizons, they work with the top professionals in the field: for example, join Dr. Marc Buie and Prof. John Keller's TNO RECON project, or help expand it's coverage area across the globe:
http://tnorecon.net/
https://www.boulder.swri.edu/~buie/recon/index.html
https://www.boulder.swri.edu/~buie/recon/reconwatch.html