Here are Pluto images of 7-12 of July, reprocessed to increase resolution. Hope they can be useful for creating a detailed global map.

http://s1.sendimage.me/7SoVqwBD.png
http://s1.sendimage.me/K6OfQwBE.png
http://s1.sendimage.me/xlkRjwBF.png
http://s1.sendimage.me/i40SkwBG.png
http://s1.sendimage.me/prGX1wBH.png
http://s1.sendimage.me/5dGqawBI.png

Rayleigh scattering at microbar levels is very small. Also, the fact that Rayleigh scattering is pretty uniform (light is scattered to all directions equally), making that in the direction of the Sun, it will block most of the sunlight, instead of enhancing it (why the sun becomes redder, not bluer during sunset). Methane gas will make it worse, since it absorbs at red wavelengths. I think we might be helped here by enhanced scattering in the forward direction, as is seen in Titan haze.



A neat paper by Jonathan Fortney shows this ratio to scale (approximately) with sqrt(Rp/H), with Rp being the planet radius and H the scale height. Both indeed decrease this effect for Pluto.




I think you wouldn't really see anything of the atmosphere in the gas-only case in either case.
If Titan-like, you might see a red glow (it is a bit more absorbing at blue wavelengths).

Rayleigh scattering is indeed pretty uniform (within a factor of 2 at different angles), though there isn't enough atmosphere present to noticeably block the sunlight. While we've heard about the pressure in microbars it might be interesting to characterize what the optical depth is with the density and scale height factored in.

Based on my back of my envelope so far I agree you wouldn't see the gas only atmosphere on Pluto. However if the Sun had Earth's intensity I think it would probably be faintly visible. With the aerosols, it would be interesting to quantify how bright the halo is the LORRI images. If future images are available at various phase angles it would tell a lot more about these aerosols.

Thanks for mentioning the sqrt(Rp/H) relationship. It is consistent with a related formula I've seen for a optical thickness of a thin layer above an observer.

I dunno. The human eye is actually a pretty decent optical system. Fully night-adapted, it can detect sources with as little as 30 photons per second. (taken from http://www.astr.ua.edu/keel/techniques/eye.html) I would bet that if a human astronaut was orbiting Pluto and fully dark adapted, she would be able to see the diamond ring around the planet - or at least a slight brightening around the no-stars circle. With all our constant light pollution here on Earth, and our tendency to go directly from brightly lit spaces to dark areas, we don't really appreciate how capable our eyes are. The LORRI image is 1/7s, so a rough comparison would be to take a digital camera and set the F stop to 12.5 (LORRI's f-stop, human eye is about f/3.2 fully dark adapted, taken from http://www.boulder.swri.edu/pkb/ssr/ssr-lorri.pdf), and take an 1/8 of a second shot. The LORRI shot shows ~102 in the "dark" areas, and about 200 in the "light" areas, so take a shot of a dark sky with part of it covered up so that it is "black", and compare the average noise on the black half to the signal on the uncovered half. If you can find a feature (such as milky way clouds or more likely, light pollution) about 2x the noise floor, see if you can detect that feature visually after full dark adaption (45 minutes). Make sure your camera is set to RAW mode, and no white balance or other shenanigans. LORRI does get a better noise floor due to being in the cold of deep space.

Looking at it another way, the eye at night integrates at about 1/30th of a second vs LORRI's 1/8, but if I understand the difference between the eye f-ratio and LORRI's f-ratio I think the eye gets an advantage there.

However, LORRI's QE peaks at about 45%@700nm (http://www.npk-photonica.ru/images/ccd47-20fi_aimo.pdf), while the human eye's night vision peaks at 507nm (http://hyperphysics.phy-astr.gsu.edu/hbase/vision/bright.html), so it is possible the haze is outside our eye's spectral window. I couldn't find any articles on the visible spectrum of Titan's high altitude haze layer for comparison, but I did see a couple of estimates of 1,000nm particle sizes. Maybe Pluto's lower pressure and less UV counteracts the lower gravity, allowing larger particles to fall out leaving the smaller ones. If we get Ralph spectral data we should know better the color of the haze (and by Mie scattering the particle sizes).

If my math is right, the sun is just below 1 LORRI pixel wide from Pluto. With accurate SPICE kernels it should be possible to place that pixel on the images. I'm at work right now and can't check against Eyes on the Solar System.

And now the back of my envelope is well and truly full.

Some quick calculation with spherical shells with hydrostatic equilibrium, R=1185km, N2 atmosphere, uniform 44K temperature, surface gravity of 0.6 m/s2, but with Rayleigh scattering parameters for a H2 atmosphere (won't make a big difference), I get about 2e-9 slant optical thickness at a microbar level at visible wavelengths.

So, indeed very little. With blocking the sun I meant all the light that is scattered (which is very little), extrapolating the case that it IS caused by Rayliegh scattering, and then arguing against it

" If future images are available at various phase angles it would tell a lot more about these aerosols." There is even solar occultation data, which should get you the spectral slope, giving an indication of particle size.

Good envelope thoughts to ponder there. I agree with the aerosols one could probably see the glow as long as the sun is blocked behind something and you're looking right next to the sun (as in the LORRI images or from the surface). If you're standing on the surface it might be best to be with the sun right below the horizon, so sunlit terrain wouldn't interfere with your dark adaptation.

Note the phase function of aerosols can change quite a bit depending on size distribution. Typically the brightness right next to the sun would be around a couple orders of magnitude more than in other parts of the sky for an observer on the surface.

Perhaps the Charonshine images will give another reference on how LORRI responds to faint extended objects. We'll need another envelope perhaps for that

Incidentally noctilucent clouds on Earth might be another case to consider, occurring at roughly similar pressures, except here we have condensation of water vapor.

Does anyone know how often there is a Charon-eclipse by Pluto, if there are any ?

every half a orbit around the sun. i.e. about every 125 years. there was a series in the 1980s, which were thoroughly exploited by scientists in may ways

Here is my take on the LORRI mosaic, rotated and very slightly sharpened. I colorized it with the 2x2 color picture of Pluto. Since this color low resolution picture and the B&W LORRI mosaic didn't overlap correctly with simple rotation, translation or shearing, I cut the color picture into 50 segments. Then I warped each segment to match the LORRI mosaic. It took me hours of work on Gimp but the result is worth it







Edit: Herobrine pointed out that a small band of terrain was missing in my mosaic. I improved the stitching to correct it and updated the mosaics.

Unfortunately I am unable to view images as large as 16K. Are you working on a map of Charon too?
The animation sounds like it will be awesome to see when it's done.

Nice work :-) I like your ideas about trying to be as accurate as possible. When I've stitched photos of scenes that I know on earth (Central Australia has some big panoramas!)
then it becomes really obvious how easy it is to majorly distort things!! ……Hᴜɢʜ…ツ

I posted an 8K version of the map now here. Perhaps Charon will be good for me to do when some additional frames come in over time.

So far I have just a few frames for the animation, I recall Bjorn had a good one earlier as well.

Beautiful!

I've semi-manually extracted the footprint of the 80 metres per pixel mosaic (P_MVIC_LORRI_CA) aka the highest-resolution image series of Pluto (AFAIK) from the NASA's Eyes application:

Click to view attachment

The zig-zag pattern is an artefact of my crude plotting and introduced to reset accumulating inaccuracy; presumably related to Pluto's changing appearance as seen from New Horizons due to the craft's high velocity.

How accurate the NASA's Eyes application is supposed to be, I have no idea (to some extent, I did this as a training exercise).

It should actually be pretty good.

Seems like a good time to reiterate a question I've had [ http://www.unmannedspaceflight.com/index.p...mp;#entry223108 ]

Basically, how illuminated are we expecting the hi-res pictures of Krun Macula to be (some graphics seem to show that part of Pluto's disk deep in shadow during closest approach), & how is this expected to impact resolution?

MOD NOTE: Moved 8 posts to start a new topic on Pluto System Cartography.

It shows the 15 frame mosaic farther north than the images we have down. How much affect that difference would have the track of the images taken near close approach I have no idea.

Looking at it last weekend I noted three passes at higher resolution than what we have down, the highest resolution pass you've shown ~80 m per pixel, another at ~120 m per pixel following a somewhat similar track, and one at ~250 m per pixel that crosses some mid latitudes terrain with varying albedos and ended in the eastern edge of Cthulhu Regio.

There is also a set of 16 pairs of images in four columns which may be a 4x4 mosaic at 3x the resolution of the 2x2 mosaic.

By the way, I've realised that the LORRI pointing in Eyes that I used to project the rest of the path is not where I subconsciously thought it were, so the footprint is probably off 1-2 pixels most places in a south-westerly direction relative to the Eyes application (but relative to the real thing: who knows..).



You can check for yourself in NASA's Eyes with the preview option what things look like (if you haven't already). The sun was certainly setting on Krun, so it should only have gotten darker there since the stereo mosaic was taken. Given the uncertainty of where Pluto was, I would guess that they've used similar settings for all of the strip, but I haven't seen such details mentioned anywhere.




It seemed very roughly correct, though, which is why I bothered to make that image at all (it also fits well with similar images posted here).



According to the list machi posted (#670), there is indeed one mosaic at 0.24 km/px and 0.12 km/px. I was also thinking about making a footprint image for those.

In Eyes, there is also this strange thing:

Click to view attachment

It's closer to closest approach, so should be able to give even higher resolution than 80 metres - but are any usable images actually taken? Today, I am unable to reproduce that result; now the LORRI FOV at that time is pointing into nightside terrain..

My version of Sputnik Planum with contrast increased to show the complexity of its surface.

Absolutely stunning! Thank you!

Ron

Oh, its been updated since I looked at it this weekend. The Pluto map now has better resolution and the position of the 15 frame mosaic looks more accurate.

As a heads up - we are slowly getting reconstructed pointing data from the NH team and putting it into Eyes as and when we can.

Yesterday a new release went live with some of that data included.

Are they downlinking selected strips of individual LORRI frames? The official Pluto photomosaic would seem to indicate this is the case:

http://photojournal.jpl.nasa.gov/catalog/PIA19858

Click to view attachment

Is there going to be a press conference today (and if so, what time)? If there is then maybe someone will ask about the high res strips.

I don't think so; I haven't seen anything. I wouldn't be surprised if there aren't any more press conferences before September, when new images and other data start coming down in great amounts.

These strips are a bonus byproduct of the selective compressed downlinks that we did shortly after the flyby- something about the way the downlink was commanded gave us the first 64 rows of the next image after the one we requested. They provide an intriguing sneak peek of unknown territory in these cases.

John

A "sneak peak of unknown territory"-- I like that description. It makes us giddy just like kids before Christmas...

--Bill

John, thanks so much for providing a quick explanation!

Very subtle Charon crescent in the new pics. Here's a bandpass filtered and stretched version:
Click to view attachment
I suppose we're mainly seeing the very thin lit crescent - no sign of atmosphere here. This is as expected, of course.

FORUM NOTICE: Since NH has completed all of its Pluto system observations, this thread for the near encounter phase will close tomorrow (1 Aug). To keep the threads at moderate lengths in order to facilitate searchability as the data download progresses over the coming year or so, new ones will be periodically opened until it's all down.

EDIT: This thread will be closed in the near future.

I am working on a "Poster Session" of the geomorphology of Pluto. This is, of course, a work-in-progress and new images are up at:

https://univ.smugmug.com/New-Horizons-Mission/PlutoCharon/

--Bill

I unwrapped the haze from Pluto in the newly released LORRI full-disk images.
Click to view attachment
That's a full 360 degrees.
It's hard to make anything out of it with the lower resolution compared to the earlier three, combined with the uneven lighting around the disk.
Here's a more horizontally compressed version.
Click to view attachment
Those both cover 0 to 15 pixels above the surface.

Here's some numbers about things; accuracy is probably within a pixel.
Treating lor_0299323899 as the base image.
Pluto center (pixels; center of top-left pixel is 0.5, 0.5): 412.125, 483.75
Pluto radius (pixels): 122ish
lor_0299323929's offset (pixels): 75, -23.75

For Sky & Telescope, Stern wrote that



http://www.skyandtelescope.com/astronomy-n...pluto-073120154

Is this about lower parts of the nitrogen glacier(s) at Sputnik plain, or something else we haven't been told about yet?

Here is a montage I made with zooms on the major landmarks in the region of Sputnik Planum, along with informal names used by New Horizons team.

Rough track of 250 m/pixel images using NASA eyes, the southern end may overlap parts of the the 7-frame mosaic we have down.
Click to view attachment

ETA: 70 m/pixel track
Click to view attachment

The 120 m/pixel track is just west of the 70 m/pixel track, perhaps with some overlap.

FORUM NOTE: As previously mentioned we've established new topics for the post-encounter phase of New Horizons as follows, and they're going live now. There will probably be chronological breaks in these as this process continues for the next year or more:

Pluto Surface Observations

Pluto Atmospheric Observations

Charon Surface Observations

Pluto System Small Moons

Reminder that there's also a Pluto System Cartography thread for discussions related to that subject.

This thread will close in the near future as discussions migrate to these new topics.

Thanks for your patience as we attempt to make the massive data return from NH as organized (and therefore searchable) as possible for everyone.