More than nine years in flight, many more years before that in the making--this is the time. Please post all comments related to New Horizon's passage through the Pluto system here.

What to expect

Reminder that despite the rather brief duration of the actual encounter, it will be literally months before all acquired data is returned so this thread will be active for an equivalent time. Intrepid TPS space journalist and UMSF admin Emily Lakdawalla has written an excellent guide to planned imagery activities. EDIT: Updated version of guide. Emily has also produced a simulation of the kinds of images that are anticipated.

FAQs

Most Forum members are advanced spaceflight enthusiasts; many are in fact professionals in space-related disciplines. Accordingly, there are no plans to post answers to questions that can be easily answered via a Google search, and we ask that everyone please attempt to do so before posting a question.

EDIT (4 Jul 15): Admin Astro0 has produced an extensive New Horizons FAQ thread.

EDIT: Review rule 1.9 and keep it firmly in mind before posting. Posts violating that rule will be deleted without notice.

____

With all that said, the most important thing by far is to witness the marvel of discovery, of exploration, of New Horizons on worlds never before seen. This is the best seat in the house for doing so, right in the comfort of our own homes. As with previous major events in planetary exploration over the past decade it is likely that not only professionals but also the press may be watching the Forum during the coming days due to its hard-earned reputation as a place for noise-free commentary and stunning contributions by amateur image processors, so please bear this in mind...

...and I can't stop smiling with anticipation and excitement. What marvelous things we will soon see. Enjoy the ride!!!

I was born the same year Voyager visited Neptune, so this is the first of this sort of brand-new-world flyby* in my lifetime. It's super exciting!

*Excluding comets and asteroids, but I've arbitrary limited the meaning of "world" to bodies that won't let you accidentally tumble off into space.

I remain curious about what can be learned from SOFIA observations of Pluto's June 29th occultation of a 12th mag star, and if it will have any bearing on the final opportunities for course correction.

Googling "New Horizons Last chance course correction" - from this article:

Same. I count Ceres as a new world, but this is the first exploration of a *system* of worlds since 1989. It's also the first exploration of a world most of us have known about since childhood, which makes it extra special to me.

First new world to be explored for the first time since Neptune with an atmosphere to speak of, I suppose we can say that much.

(though Titan almost ruins this one, too)

I always think twice before saying anything not to add noise to this wonderful place, but I can't resist this time since this encounter will finally put an end to a 26 years long wait for me. I was 14 in 1989 when, right after the Neptune flyby, I started dreaming of seeing "the last one" up close in my lifetime.

There were times when I doubted it would happen but thanks to Alan and the amazing team behind this endeavour, that long wait will soon end in the most delightful way ! So, thanks a milion times to all the people involved for making this fourteen/forty years old happy

Going back to lurk mode now, eyes wide open !

Nature has posted an interesting non-technical article about the difficulties faced by New Horizons' two navigation teams.

MOD NOTE: My fault for not making this clear in the kickoff post, but please review rule 1.9. Pluto's classification as an object will not be discussed here, period.

Fully understand the emotional connotations of this ongoing debate, but it is for precisely that reason that the topic is banned. One post removed for that reason. Please don't try to dance around it. Thanks.

Maybe a little fun; is there a poll facility on the site? We could puree our collective brains into a jar and come up with the official unofficial UMSF list of predictions. For example,

New Horizons will see: (choose one)
No visual evidence of an atmosphere on Pluto
Limb haze on Pluto
Clouds on Pluto

New Horizons will see: (choose one)
No visual evidence of an atmosphere on Charon
Limb haze on Charon
Clouds on Charon

Number of new moonlets that will be discovered: 0, 1, 2, etc.

New Horizons will see:(choose one)
No evidence of recent geologic activity of resurfacing events on Pluto
Evidence of recent resurfacing but no ongoing activity on Pluto
Ongoing activity (geysers/etc caught in the act) on Pluto

New Horizons will see:(choose one)
No evidence of recent geologic activity of resurfacing events on Charon
Evidence of recent resurfacing but no ongoing activity on Charon
Ongoing activity (geysers/etc caught in the act) on Charon

Hydra and Nix will be: (choose one)
Roughly spherical
Irregular in shape
Artificial, the Mi-Go shipyards of Yuggoth (sorry, big Lovecraft fan)


Etc.

A bit of saccharine sentimentality, echoing an earlier post:

We will almost certainly never again in our lives see a world this big up-close for the first time, and perhaps no people will for many generations to come.

The biggest world closer than Neptune which we haven't seen up-close is Pallas, a quarter Pluto's size.

For fans of first looks at a world, this is the Omega. We'll probably get first looks at many small bodies: Comets, asteroids, and hopefully TNOs in the path of New Horizons, but to the extent that geological complexity requires some sort of minimum size, this is the last gasp.

The next time we get new science of such an interesting planetary body of this size, it will be something extrasolar, just a pixel across, giving up a few secrets to light curves, photometry, and spectroscopy.

Savor this. It's the last time.

There's always Eris, although I doubt I will still be around when it is finally visited.

Perhaps I'm being too optimistic, but I like to think we'll visit another big KBO in the next 50 years -- especially if Pluto proves to be really interesting. Probably not Eris, though, since it's so far away right now. I predict Haumea will be next, and hopefully some of us will be around to see it.

Either way, this flyby is historic and I'm thrilled to be around to take it in.

Sedna too, assuming a propulsion breakthrough in a couple of decades.
Also the unmapped hemispheres of Triton and the Uranian moons (though they're not quite in the same category of 'first time', I'll admit!)

Copied a portion of Habukaz' calculated LORRI resolution & major object image widths for the next two weeks as a quick reference. Original post here:


29.06: 86.5 km/px - Pluto 28 pixels across, Charon 14 pixels

01.07: 74.7 km/px - Pluto 32 pixels across, Charon 16 pixels
03.07: 62.6 km/px - Pluto 38 pixels across, Charon 19 pixels
05.07: 50.9 km/px - Pluto 47 pixels across, Charon 24 pixels
07.07: 39.0 km/px - Pluto 62 pixels across, Charon 31 pixels
09.07: 27.1 km/px - Pluto 89 pixels across, Charon 45 pixels
11.07: 15.2 km/px - Pluto 158 pixels across, Charon 79 pixels
12.07: 12.7 km/px - Pluto 189 pixels across, Charon 96 pixels

It is much easier to use these formulae to determine the size in pixels of the objects :

Pluto : 392/N px
Charon : 205/N px
Styx : ~3.5/N px
Nix : ~7/N px
Kerberos : ~5/N px
Hydra : ~8/N px

resolution = 5.9*N km/px

where N is the number of days (decimal number) before NH goes through the planetary system.

[i]For example, right now the number of days remaining is 15 days 5 hours, this gives 15.2 days.

The diameters are :

Pluto : 26 px
Charon : 14 px
Styx : < 1 px
Nix : < 1 px
Kerberos : < 1 px
Hydra : < 1 px
resolution = 90 km/px

A view of sizes, with the Moon as a model, full size :

Click to view attachment

The SOFIA telescope is observing Pluto occultating a star today; does anyone know if results of this will be available before the Pluto encounter? It would be interesting to know if Pluto's atmosphere is still growing, remains stable or has started shrinking.



Another option would be to have a separate thread where members are invited to post their predictions for the Pluto system. I think it could be fun.

@fred_76 At what point do those formulae cease being reasonable approximations? You have an asymptote to infinity on the day of the flyby.

Pluto+Charon today, magnified 2.5×.
EDIT: Added colorized version.

In fact there are two things :
1) the approximation of the inverse tangente atan x ~ x because the diameter of the planet by far smaller than its distance from NH,
2) the asymptote you talk about

In practice, those formulae are quite valid until a pair of hours before "contact" as NH travels at 46500 km/h which is >> planets dia.

Trying to compare one of the raw images from today (rotated only first from left, rotated and interpolated scaling second from left) with two deconvoluted releases from 8 June and 15 June (respectively):

Click to view attachment Click to view attachment Click to view attachment Click to view attachment

Nix and Hydra viewed the 29th june's bin x 1 images. Kerberos still not visible.

Click to view attachment


Fred

Thanks, fred_76. This is a good way to convey the progression.

It's particularly poignant to see that 3-days-out image, because that's the best view we'll get of the anti-encounter hemisphere (AEH).

However, I'll point out that the Moon is about 1.5x the size of Pluto, so while Pluto will appear that *size*, we'll see Pluto at 1.5x the resolution that those Moon photos show. Consequently, we'll see the AEHs of Pluto and Charon at the same resolution as your left 2-days-out image of the Moon.

It's quite evident there that Tycho is a crater and one could surmise that Copernicus is. Otherwise, one could interpret the features in comparison to the better imagery of the other hemisphere, but on its own, it's still quite murky. The spectral imaging will add a lot, so that units on the AEH can be identified as likely similar to corresponding features on the encounter hemisphere.

The Charon-shine imagery may fill that in wonderfully, though, and even more important, give us a look at the winter pole that won't otherwise be seen at all.

The data set will basically be a tale of three Plutos: The encounter hemisphere, the anti-encounter daylight "hemi"sphere, and the winter pole. Similar for Charon, but we will only see its winter pole in Plutoshine from 3 days out, so we'll only get albedo/spectral information at very low resolution. On the other hand, Plutoshine is 4x brighter than Charonshine.

As a reminder of "shine" imagery, here's Iapetus in Saturnshine.
http://www.nasa.gov/mission_pages/cassini/...a/pia06168.html

Saturn is, of course, a hell of a lot bigger and brighter than Pluto or Charon, but it's also 200 times farther from Iapetus than Charon is from Pluto, so Charon occupies ~2x the area in Pluto's sky that Saturn occupies in Iapetus'. So Charonshine on Pluto is only a few times dimmer than Saturnshine on Iapetus.

So you won't remember how we saw Neptune on rasterized photos in the newspaper. Earth has changed a lot since those summer days of 1989, amazingly by now letting all of us have a front-row seat to, and be part of, space exploration. Thanks UMSF!

@JRehling : I Know the moon is bigger than Pluto, therefore I redimensionned it's image so that it has the same size as Pluto, when views from the same distance.

Now, for sure, as Pluto is certainly not made from the same materials as Moon, it's aspect will be different.

Ah, sorry, Fred - I misread! My fault. And I'm doubly sorry, because that means the resolution will be 2/3 of what I'd thought.

The Moon seems, to me, to be unusually hard to interpret in its full phase. A lot of worlds, like Io, seem to look pretty good when full, but the Moon becomes a smear of maria, highlands, and rays. I hope Pluto is easier to make sense of in those distant, full images.

Io may look pretty good when full... but it sure wasn't easy to interpret!

I think the difficulty in interpreting the Moon at small phase angles (full or nearly so) is repeated for all worlds, notably in recent times Ceres and now Pluto. When Ceres looked twice as detailed as Pluto does today, we had interpretations of giant rifts and canyons on this very forum. Only resolution saves us.

Phil

Here are the 2015-06-29 05:03 images. This is a stack of three images enlarged by a factor of 4. Two images were also obtained 6 minutes earlier that I could have added to the stack but the resolution is now probably high enough for Charon's changing position relative to Pluto to possibly have become a minor problem without correcting for it (but I notice that machi used them successfully). This image is also a 'milestone' of sorts because the size of Pluto (and the distance in pixels between Pluto and Charon) is now so big that from now on I will probably post images enlarged by a factor of 3 (or smaller) instead of 4.

Click to view attachmentClick to view attachment

And this is Pluto with a lat/lon grid:

Click to view attachment

This reveals that the pole may be close to the center of terrain that is slightly darker than the terrain farther from the pole. This is a somewhat tentative result though.

Charon's shape looks slightly irregular here (and also in machi's version), probably for the same reasons that Pluto looked slightly irregular at lower resolution (Pluto now appears perfectly spherical).

Here is slightly improved version. It's now made from 5 stacked images (previous was made from 4) and it's corrected for Charon's motion so Charon is now sharper.
BTW, darker area around Pluto's pole is almost certainly real feature because it's visible also in previous set from 28. June.

These last few images remind me of Titan, sans atmosphere.

Probably-stupid quedtion, There are possibilty that the Black Long feature are a metane or azote liquid lake?

Still too early to tell (17 million km to go!). If these images were coming out in a newspaper, I would not be taking a magnifying glass to them and exclaiming that Pluto is made of tiny coloured dots!

Two weeks left....

Too cold, I think. Wolfram says methane's freezing point is around 90K and Pluto's colder than that. At least, it is today. But the bright and dark regions on the latest Pluto images reminded me of the bright highland and dark lowland regions (probably wrong nomenclature) on Titan. If we see something like that on Pluto, that would be very interesting indeed.

Daniele, I don't think that it's possible for those to be methane lakes since Pluto's atmospheric pressure is far, far lower than even that of Mars; around three micro(not milli-)bars per this NASA fact sheet.

I remember a day when triton was theorized to have lakes of methane.

Ciao!

One stack of yesterday images (full 400%)
I cannot wait to focus on these features!

The dark features may be more akin to those visible on Triton:

http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA00329

Well, I was hopeful that all of the June 29 images could be stacked but I think there is actually enough movement that it degraded the quality too much for my liking.


Single frame on left, blink animation on right

June 28, 2015 - 2 images
Click to view attachment Click to view attachment

Charon is absent in one of the images and so I simply excluded it.

June 29, 2015 - 04:56 UTC - 2 images
Click to view attachment Click to view attachment

June 29, 2015 - 05:02 UTC - 2 images
Click to view attachment Click to view attachment

June 29, 2015 - 05:03 UTC - 1 image
Click to view attachment Click to view attachment

Keep in mind these are all limited data stacks so noise is likely to be apparent and different features are also likely to pop in and out of visibility.

I thought I would see if I could tease some information out of the dark areas using a single image of Pluto/Charon. The original is the 6/29/15 at 05:03:10 UTC 1:1 bin image released today.

Click to view attachment

No stacking on this one. The only processing was a 4x enlargement followed by contrast/brightness/midtone enhancements.

If anyone would like to speculate about clouds the wispy area near Pluto's dark band certainly could be a starting point or it could be ice. Charon's anti-dark pole almost looks like it has some relief showing.

Anyway, just an attempt to find more information from the data (that will hopefully be obsolete within a week).

When we get images this quickly from New Horizons, it very much reminds me of watching Dr. Albert Hibbs and his guests at JPL explain Voyager images as they appeared on the monitors in real time during the Saturn/Uranus/Neptune encounters.


Andy

Will there be anything like that during the NASA TV coverage during the week of the flyby (i.e. seeing mission control)? I've read Emily's blog post but it seems like it will be a combination of press conferences and hammering refresh on the raw images page, not that that's a bad thing....
(Speaking of which, some dedicated Hydra targeting has started: http://pluto.jhuapl.edu/soc/Pluto-Encounter/index.php )

Refer to the first post of this thread, and esp. to Emily's article about planned activities. The data rate from Pluto's distance is nowhere near as high as it is during a Jupiter encounter (1kb/sec vs. something like 38 kb/sec), so we're likely gonna see just a few images with a good deal of time between them on encounter day. Per Emily's article again, only 1% of the acquired science data will be returned then.

Yep, I know how slow it will go considering how thin the data-pipe is over these distances. Just wondering about the coverage itself, beyond the critical 'beep' on the 14, all the live reactions from MC (which I'm such a sucker for!)


Also: SOFIA's observations got some good data: http://www.sofia.usra.edu/News/news_2015/06_29_15/index.html

Best I can do with the June 29 data. I think temporal blurring is subtle but likely problematic at the same time, even at this distance.

Click to view attachment

Nix and Hydra the 29/06/2015 in the bin x1 images :

Click to view attachment

Close up on Pluto and Charon :

Click to view attachment

It seems there is a huge impact crater on Pluto...

Fred

We can't be seeing a crater shadow yet; NH is still at a tiny solar incidence angle until nearly closest approach; it's 'only' a dark patch (see the previous thread, with Bjorn's illustration).

In those images, the dark band near Triton's equator looks a lot like the dark bands near Pluto's equator; though it appears to be somewhat brighter on Triton.



In rotation videos, the shape looks wrong; too oblong.



It could though be possible to see different surface composition due to altitude - i.e. like mountains on Earth may have a white snow cover.

However, the light coming from the Sun (the area facing the Sun is shown with the yellow dot) is quite correct to explain a potential crater rim illumination on the southern hemisphere of Pluto :

Click to view attachment

Here's my take on the 6/29 images.
5 image stack with unsharp mask, minimal level manipulation, to preserve the overall albedo variations.
I think that the pole shows up nicely this way, and the rest of the details are quite convincing.
Not that different from the other versions posted here, I guess that's a good thing :-)

Click to view attachment

Here are the phase diagrams of methane and nitrogen. As you can see, both are stable only as solids in Pluto's conditions (T = 35-55 K [-238 to -218°C], 10-20 microbar [0,00001-0,00002 bars])

I don't think *anything* endures as a liquid at pressures as low as Pluto's, at least nothing that's likely to exist in reasonable quantity at Pluto.

Interestingly, hydrogen and neon are liquid at Pluto's temperatures and 1 ATM. Maybe there could be underground liquifers of those, but they'd probably be in tiny abundance unless something has broken down a quantity of H2O. I doubt if we're going to see any signs of present liquid anywhere on Pluto, but some past impact/geological events may have left signs of melting behind. As I noted earlier, Charon may be even more likely to show this.

Excerpt from a blog post on the potential for liquids on Pluto: