I've been processing some of the high resolution Galileo Ganymede images recently. As far as I know the two mosaics below have not appeared at the official websites (at least not in this form) so in a sense they are 'new'.
The first one was obtained during the G1 flyby in 1996. It covers a part of Memphis Facula which is centered at roughly 15°N, 132°W. The images were obtained at a distance of approximately 5000 km from Ganymede's center.
Bjorn, honored to be the first to complement you on this remarkable work!
Interesting that Ganymede seems to have its own 'look' on this scale. The crater rims seem to be quite rounded, almost eroded in appearance...I'm at a loss to explain this, unless they are truly ancient and this is the result of micrometeoroid action over the ages as we see on the Moon. However, this conflicts with the existence of very prominent fracture/faulting features...odd indeed.
One of the things that seems to happen on Ganymede and even more so on Callisto is the sublimation of ice by "dirty" regolith. Icy dirt gets hot enough in the afternoon to sublimate ice and darken itself. That accelerates the process. At the same time it can tend to creap downslope, tending to thin and expose more ice on elevations and slopes, lightening those surfaces and slowing the ice evaporation process. That seems to be very important in the highest resolution images, from what I've read (and also speculated myself). Callisto high-rez images show the resulting topography best.
Great work! It really is amazing how many good Galileo mosaics/images never became public release products. Here is one from G-2 (use the link for a higher resolution version).
http://www.strykfoto.org/g2-1a.jpg
Thank you Bjorn. That was a real treat.
Too bad it's such a cliche now, but the term "alien landscape" would be most appropriate here.
Wow! Thanks yet again, Bjorn!
Temperature-dependent selective erosion aside as Ed correctly mentioned...this is odd. The 'hummocks' clearly are more recent than the craters, and actually seem to be destroying them over geologically recent time scales. Ganymede seems to be far more active than I thought....
Can't help but toss my hat in the ring with this obscure observation from the E12 orbit in December 1997. Galileo passed within 20,000km of Ganymede and took this hard-to-decipher oblique pan across the floor of the giant Gilgamesh basin. The fractures scale all the way down to the limit of resolution in the right-hand portion of the mosaic.
Apparently we're seeing similar temp controlled sublimation at Iapetus and Hyperion. There's very un-intuitive feedbacks going on in the processes, I suspect, and quick-and-dirty arm-waving analysis can only go so far. These terrains will look *STRANGE* when we finally get some hard lander down on these objects. The fractured and faulted ice terrains of Europa and volcanic terrains of Io (not the S02/Sulfer etched terrains and the like) will look positively familiar, I suspect.
Thanks a lot to all of you for these great mosaics !
These pictures were taken 10 years ago, and there is still a lot to do with them.
Did anybody try to assemble the very high resolution pictures taken during G1 over Xibalba Sulcus ?
Due to their "bad" quality, it might be difficult. I even don't know if they really overlap !
I also did not find any mention about the G29 images.
What about the regional and color polar cap boundary mosaic near Perrine Regio ?
Finally, there were these pictures taken when Ganymede was in Jupiter shadow in order to look for aurora events :
http://pdsimg.jpl.nasa.gov/outdir/4846r.img.gif
I never heard about them in any publication.
As you can see, my "frustration" is still quiet high ten years later, and that's why I really enjoy your posts.
Marc.
Well, I have this color mosaic I put together a few years ago from G29. I will say that because I made it years ago, I used relatively crude methods compared with what I use now, but at any rate, here it is.
I might as well join the fray too:
Both of these are from a non-targeted encounter during orbit C9.
http://pirlwww.lpl.arizona.edu/~perry/C9GSSULCUS01.jpg
C9GSSULCUS01
Distance to planet center: 84379 km
This four-image mosaic covers portions of Xibalba Sulcus (roughly N-S set of grooves and ridges at the center of the mosaic) and Nineveh Sulcus (the roughly E-W set of grooves and ridges on the right-hand side of mosaic). This mosaic is roughly centered near 28 N, 82 W. Xibalba Sulcus seperates Galileo Regio on the left and Perrine Regio on the right.
http://pirlwww.lpl.arizona.edu/~perry/C9GSGLOBAL01.jpg
C9GSGLOBAL01
Distance to planet center: 201468 km
This seven-image global mosaic is centered on Ganymede's leading hemisphere, with Galileo Region on the limb at upper left, Perrine Regio near the terminator at upper right. The bright ray crater Cisti can be seen near the bottom.
Here is a montage of Galileo Callisto and Ganymede views I did. I could swear I have a version of the Ganymede image somewhere without the horribly saturated whites, but I am not sure (it was a victim of my crash a few years ago, but I could swear it was backed up). In both cases, the color data is filled in from other orbits and Voyager.
Click the link for full resolution (keep in mind that full resolution is keyed to the Callisto image, which is much smaller).
http://www.strykfoto.org/calgan.jpg
I have now completed my earlier post with an improved Ganymede and added Europa and Io.
http://www.strykfoto.org/calgalileans.jpg
Striking view, Ted!
Thanks Ted. really nice.
The color mosaic of Perrine Regio is exactly what I was looking for.
However, the polar cap boundary is not really obious.
Marc.
It is the highest resolution I made it. The Ganymede and Europa mosaics are much larger, and the Io mosaic is slightly larger, but the Callisto mosaic is at full size.
Ted
It's surely the most difficult mosaic to construct (if not impossible !). At least you tryed. Thank you Bjorn.
Indeed, the four images may not overlap. The same happened with the G1 Uruk Sulcus high resolution mosaic, but in that case, there were nice Voyager 2 context images.
Even if the four pictures do not really match, the mosaic anyway gives a better idea about the fine structure and topography of this terrain at high resolution.
Concerning the polar cap boundary, I did not expect to see something really sharp, but at least less gradual !!
Ganymede is still one of my favourite "worlds", and it's really a pleasure for me to follow this thread.
Marc.
...very cool, JR! Quite the budding planetary scientist you have there!
I tried getting my daughter interested in this back in the 80s, but, alas, pictures in books didn't have the same allure as computers do to children nowadays (to say nothing of wonderful, detailed images like Ted's!) She knew how to say "Louis Vuitton" long before she could say "Mars", so I knew it was a lost cause...
These stories are adorable...my four-year old says that I play with moons and make puzzles with them, but no names are known to him but Saturn's. Kudos to Ted for a magnificent montage and Bjorn for assembling some of the fugliest images in planetary exploration history into something vaguely comprehensible. I'm tossing in a context scene of the Memphis Facula mosaic from the first post...those Voyager images make things far easier to understand where available.
Thanks, Vex! Long time no see, welcome back!
Excellent mosaics! I browsed through the Planetary Photojournal to see what other Galileo observations were either 'forgotten' or incomplete.
Here are some mosaic-attempts of mine:
G7GSKITTU_01 Kittu Crater
On the PPJ this observation was merged with G7GSKITTU_02 color:
http://photojournal.jpl.nasa.gov/catalog/PIA01611
Here is the original G7GSKITTU_01 without color:
G2GSURUKSL01 Uruk Sulcus. Stereo companion to G1 Uruk observation
G7GSNEITH_01 Neith Crater.
Same as this PPJ image: http://photojournal.jpl.nasa.gov/catalog/PIA01658
But at full-resolution.
G2GSNIPPUR01 Nippur Sulcus
At the PPJ:
http://photojournal.jpl.nasa.gov/catalog/PIA00497
http://photojournal.jpl.nasa.gov/catalog/PIA01086
Full resolution:
And for a different angle, an distant J0 crescent (sorry, I couldn't resist).
G2GSTRANST01 Marius Regio
PPJ:
http://photojournal.jpl.nasa.gov/catalog/PIA01087
http://photojournal.jpl.nasa.gov/catalog/PIA01091
Full mosaic:
G2GSGRVLNS01 Byblus Sulcus
PPJ:
http://photojournal.jpl.nasa.gov/catalog/PIA01088
a wider view:
G8GSCALDRA01 Sippar Sulcus calderas
http://photojournal.jpl.nasa.gov/catalog/PIA01614
http://photojournal.jpl.nasa.gov/catalog/PIA03214
G8GSFRACDK01 Southern border of Galileo Regio
http://photojournal.jpl.nasa.gov/catalog/PIA01616
For some reason this already small image was made even smaller. The original:
G8GSREGCON01 Marius Regio / Nippur Sulcus
http://photojournal.jpl.nasa.gov/catalog/PIA01618
Same here.
G7GSNICHOL01 Nicholson Regio / Arbela Sulcus
http://photojournal.jpl.nasa.gov/catalog/PIA01612
http://photojournal.jpl.nasa.gov/catalog/PIA01613
28GSNICHOL02 Nicholson Regio context
28GSNICHOL01 Nicholson Regio High resolution
PPJ: http://photojournal.jpl.nasa.gov/catalog/PIA02571
Here is a set that shows the problem with relying on one filter sent at full resolution combined with color data with 2x2 binning. To the left is a photojournal release, and to the right is my version. I used all data available for the larger features, and an overlay from the full resolution frame to bring in fine detail.
And here is something from my earliest works (i think that this is actually my first better mosaic). Galileo Regio mosaic.
Ganymede's south pole region from Voyager 2. All images resampled to resolution 500 m/pix. Real resolution is around 550 m/pix.
Color is from wide angle images (orange, green and violet filter).
That's very nice!
Superb work!
Beautiful!
One more example of what can be done with the Voyager images using modern computers and software. This is one of the best Voyager mosaics I have seen of Ganymede and of course much better than any of the official stuff produced back in 1979.
Thanks!
Yes, new reprocessed images from Voyagers are mostly better than old official versions, but I have great respect to people who made this old images.
With much slower computers and not very user friendly software, it must have been really damn difficult.
Many were processed using a VAX. I can't even imagine it.
Very impressive Machi.
The terrain in the far south near the terminator is incredibly similar to Enceladus' south polar terrain (on a much larger scale of course)
Brilliant work, Daniel!
I'm beginning to think that a website based upon the NASA Planetary Photojournal site, but dedicated solely to 'amateur' image products, might be a good way of collating the ever-growing portfolio of great work produced by people on here. We could even call it the 'UMSF Photojournal'.
Oh, Ted: I used to own a VAX. It was the best darn vacuum-cleaner I've ever had...
Ian, I have actually similar idea and in fact it's partially on the way. Because I haven't my own server, I must use public server with 300 - 500 MB data storage.
So I suppose, that in first phase I will create simple gallery with my images (png's) and then (second phase) I will be using only thumbnails with location reference to full image or page with image.
There is minor problem with my programming skills, so I will plan only simple html gallery with thumbnails and basic informations about every image.
This is a colour global view of Ganymede, taken using Orange, Blue and Violet images (in the RGB channels respectively) from Voyager 2. I made it using ISIS around 1998 or 1999, it's an orthographic reprojection of a mosaic of the antijovian hemisphere. I don't think I stretched the histograms in the component images at all.
I wish I could remember what specific images I used (I'm reasonably sure that I was using the images that http://pds-rings.seti.org/browse/VG_0025/BROWSE/GANYMEDE/C2063XXX/). Annoyingly I can't find my notes on it - I'm lucky I actually managed to find the image itself! . I think there were around 39 images in total (about 13 for each filter)?
I do remember that I had to manually match the images - I didn't have IDL or any of that other fancy stuff, working in a UK university that didn't have the funds to buy it. I looked at each adjacent/overlapping image pair in a given filter, looked for a minimum of three match points between the images, and noted down the pixel locations for all of them in a little black book and in a text file that ISIS would read, and then did that several times for each overlapping image pair - it took weeks to find all the match points, and sometimes ISIS would still just not match the darn thing properly and so I had to go back and find different ones. As it is it nearly broke the computer I used to make it (which of course was great for the time and completely laughable by modern standards), and I think the end mosaic (in original .cub format) was over a gigabyte in size! I'd have to leave the ISIS script to take it from level 0 to level 4 running overnight and hope it all worked. I also used updated SPICE data for Voyager that I got from Tim Colvin at RAND Corporation (that IIRC wasn't in ISIS at the time). The resolution of the mosaic is 2 km/pxl.
Probably not awesomely useful for science, but I'm pretty proud of it considering the effort it took to make it - hope you like it .
>>I wish I could remember what specific images I used (I'm reasonably sure that I was using the images that http://pds-rings.seti.org/browse/VG_0025/BROWSE/GANYMEDE/C2063XXX/). Annoyingly I can't find my notes on it - I'm lucky I actually managed to find the image itself! . I think there were around 39 images in total (about 13 for each filter)?
yep those are the numbers. it was a 3-color 6-frame mosaic (18 total). i dont know why it didnt cover the poles. the basic color patterns of ganymede are in this mosaic: the reddish color of dark terrain, the different colors of the dark rays, even the bluish polar caps in a few spots. i used it in the Atlas to fill certain areas but used lower resolution Galileo color because that included IR data globally.
One of my Ganymede mosaics uses that set with wide angle data for the poles.
Only 18 images? Seemed like a lot more! (maybe I'm thinking of how many overlapping pairs there were, or something).
So barring the slight difference that using OBV filters instead of RGB ones would make, is this actually close to the colours that Ganymede would have if we were there looking at it with our own eyes? There doesn't seem to be much of a colour/brightness difference between "bright" and "dark" terrains (the ejecta around Osiris is much more noticeably brighter though).
Very nice! Thanks for doing that, I've often wondered if there was any software that could interpolate between the filters.
its about as close to natural color (at high resolution) that we can get right now. kind of a pale milk chocolate. The moons not made of green cheese after all. we could sell land parcels on the chocolate moon!
Hooray! I just managed to find all my old Galileo and Voyager image mosaics and notes (I thought I'd lost them all)! I even have the scripts I used to make some of them in ISIS too (complete with matchpoints)!
So I may be posting a few more mosaics here, if they'll fit (and the scripts, if people want them) .
Thanx!!
Since the scripts are just text files and shouldn't take up too much space, I say post 'em. I have fantasies that I'll get back into using ISIS for image processing but I'll have to get myself a Mac first...
Great mosaic, especially when keeping in mind that it was made more than 10 years ago. Reminds me of when I made my first 'real' (and big) planetary map towards the end of the 20th century - it was of Ganymede. My computer was completely swamped, a lot of time was spent on calculation runs and it crashed several times. Now I could make a *much* bigger map with ease and much more quickly.
Needless to say, seeing the scripts would be interesting. There are some ISIS users here.
This is the global mosaic of Ganymede's trailing hemisphere that the script makes (at least I hope it's trailing, I get leading and trailing mixed up!) - note that this doesn't include any other images, it's just a reprojection of the antijovian mosaic:
And here's the leading hemisphere mosaic (huh. Interesting. I thought I did this in a separate post but it seems to have combined them - the one on the left is the trailing hemisphere, the one on the right is leading):
I was going to start a new thread for this but I think for now I'll keep posting my stuff here.
I also made a global colour mosaic of the sub-jovian hemisphere of Ganymede from the Voyager 1 images, but that proved more problematic, largely because some of the blue filter images were blurry. I made global mosaics using orange, green, blue, violet and UV filters, and here's what I came up with (details are all in the captions within the images).
The OBV (Orange/Blue/Violet) is the same filter combination as my Voyager 2 mosaics posted above, but you can see the issue with the blurry blue filters in the top left part of the image.
To correct the blurriness (aesthetically anyway), I cheated a bit - I took the Orange mosaic, fiddled with the brightness/contrast a bit (went into Photoshop > Adjust Brightness/Contrast, and set -10 Brightness, -5 Contrast) so it looked kinda like the Blue one, and put the modifed orange mosaic in the Green channel of the image to replace the blue one that was there. So technically this mosaic is Orange/Modified Orange/Violet in the R/G/B/ channels.
The result is that the blurriness isn't there anymore, but it's no longer accurate in appearance. Still, it doesn't look too bad IMO.
The next attempt is actually as close to true colour as we're going to get here - a colour mosaic using Orange/Green/Blue in the R/G/B channels. Unfortunately I only could find a strip of Green filter images so the central part of Ganymede is the only part that's in (nearly true) colour. I really like how this one looks, it's just a shame that more of Ganymede wasn't covered by all three channels.
All this talk of filters makes me wonder - why did they not include a red filter in the ISS, so at least we could get some true colour pictures? (that said, looking at the filters here - http://pds-rings.seti.org/voyager/iss/inst_cat_na1.html#filters - it looks like Orange extends into the red a bit too. Though "Green" actually seems to be more like yellow?)
And finally, just for kicks I tried an OGU image (Orange/Green/Ultraviolet), which wouldn't really look like true colour at all and doesn't actually have that much overlap between all three filters (the only part that does is a thin strip on the left of the Green, but it blends in somewhat with the yellow overlap so it's hard to make out).
I'll see if I can dig up the scripts for these. Anyone manage to get the Voyager 2 script working at all?
EDG, any idea why you have color shifting in the 3-color footprints near the terminator? It looks to me the green and blue filters are darker there than their neighboring footprints, causing some reddening there. For fun I tried coaxing your O+UV color near the left limb to the OGB in the center and I can get them to match more closely than the actual OGB footprints agree.
I am trying to find my notes...I did that image three or four years ago. I'm pretty sure I used OG(B+UV) where I could. Where I couldn't, I used whatever was available and shifted it to match the color in wide angle shots.
I didn't notice that problem.
Here is my latest version of Galileo's E6 mosaic (with help from other orbits).
That is lovely. Is the shift from reddish tones to more gray (or more blue) colors from mid-northern latitudes to northern polar latitudes real or a result of some boundary between image coverage?
Toward the poles, it definitely seems grayer.
I've found the scripts for the Voyager 1 mosaics, but they are broken down into individual filters. It also looks like I did it as a two-stage process - I have one script that updates the SPICE labels with the RAND data using spicelab, and then I have the script that makes the mosaic (which refers to the rmb file created in the first part of the process). Each filter's zipfile contains a RAND#.rmb that's already been generated. Does anyone know if this is even necessary anymore, or has the SPICE data been updated to something more accurate in the years since I did this?
So here's the scripts for each filter. The randcolour.zip file is the SPICE label updater but for all the images involved in all the filters that I use here - it just puts the updated data into a single file called RAND.rmb, instead of separate rmb files for each filter. Unfortunately I don't have a single script file that you can edit to make all the mosaics at once.
As before, I'd advise looking through these files and checking that they'll work in your system (e.g. the cd2isis command in RANDcolour.txt script refers to IMQ files mounted locally, so that won't work without being changed). You'll also have to look at the scripts to see what IMQ files you'll need (easiest way is to check the input2.txt files) And use the scripts at your own risk .
It's supposed to be an irradiation thing - the boundaries roughly match the latitude where magnetic field lines transition from closed (equatorial region) to open (polar) so charged particles can spiral down there and pepper the surface. Or so I've read.
thats right, those are the aggregate effects of small scale deposits within the two polar caps. well documented. also very visible in the Atlas in global views and at high resolution, where it is seen as pole-facing bright deposits
Titan has veiled wonders and Io suppurates, but to my eye from a distance Ganymede is just the most beautiful moon in the solar system. Thanks to all for the magnificent images.
EDG Have you done other moons?
Europa maybe?
Here is a new global mosaic of Ganymede from Voyager 1 images:
Bjorn that is incredibly good. Thank you for your amazing work!
That's spectacular work, Bjorn! Well worth the time invested in it!
I've started assembling some of the various Voyager 2 mosaics of Ganymede. Since this was a relatively close flyby and I'm not skilled in reprojection techniques, I'm just working on small submosaics that I can hand-assemble without too much difficulty.
https://flic.kr/p/HonZMc
https://www.flickr.com/photos/132160802@N06/27163882121/sizes/o
https://flic.kr/p/HuCFK8
https://www.flickr.com/photos/132160802@N06/27234647105/sizes/o
I love this moon's landscapes. These images almost make me feel like I'm flying over it in person.
Od's tonsils, Bjorn, that is amazing!
Voyager 2 got a great mosaic of the ~600 km wide Gilgamesh Crater, which was sitting near the sunset terminator around the time of the flyby. With normal image processing it's pretty easy to see the ~300 km inner basin, as well as the scarp surrounding hummocky terrain that marks the edge of the main crater at a diameter of 590 km. To the south of the crater, there is a hint of some smoother terrain, but it's hard to interpret.
https://flic.kr/p/H6ZoBw
https://www.flickr.com/photos/132160802@N06/26978407420/sizes/o
When I was processing this, I accidentally pasted in another copy of this photo in a difference blending mode. As it turns out, a slight offset highlights the surface roughness pretty well, and the smoother terrain really pops out:
https://flic.kr/p/GAHrPU
https://www.flickr.com/photos/132160802@N06/26647118054/sizes/o
http://www.lpi.usra.edu/meetings/LPSC98/pdf/1949.pdf, this zone is interpreted as a continuous ejecta sheet, which extends out about 1,100 km from the crater's center.
This is all fantastic. Ganymede is truly one of the more beautiful worlds. As I've gotten into astrophotography over the last year, I've learned quite a bit about deconvolution; it may be more accurate to say that I've used deconvolution. I have found myself saying, "This is where the magic happens" as I watch blurry images suddenly become wonderful through processes I can only partially explain.
This goes a bit off the title subject, but I obtained the following image of Ganymede using a NexStar 6se and deconvolution, with the single aim of seeing if I could resolve surface features, and it worked better than I expected. I imaged Ganymede when Galileo Regio was centrally aligned, and I certainly succeeded in resolving it. This image is with a green filter: The color image I got from RGB was not so good, so I'll just offer the green version alone. I'm not sure I know of anyone else getting surface details with a telescope of this size.
Bjorn's global view has an intriguing crystalline look to it. I would guess that a global cylindrical map around 8K in size might look nice with these new mosaics.
Here's what Jupiter looked like the same night. That was indeed the best result I ever got for Jupiter.
I'm also attaching a demonstration of the power of digital refinement. These are from the red channel.
Panel #1: A particularly bad single frame.
Panel #2: A particularly good single frame.
Panel #3: The result of stacking >800 frames.
Panel #4: The result of wavelet processing (performed by the program Lynkeos) on the image in Panel #3.
I did some reading on how others used wavelets and then played with the parameters on my own to arrive at my personal favorite settings; they depend on the target and the night, but I have a favored starting point to get me going.
I've finished going through the Voyager 2 narrow-angle data set. The main prize is this 87-frame clear filter mosaic.
https://flic.kr/p/Htr5CZ
I really want to recommend checking out https://www.flickr.com/photos/132160802@N06/27221066281/sizes/o, because it's like getting to see the New Horizons MVIC image of Pluto for the first time all over again!
It looks like the imaging team broke down imaging into multiple smaller mosaics with a little bit of overlap. At the rate that Voyager was approaching the moon, I don't think taking the entire mosaic in a single go would have been possible with the huge change in viewing geometry over the three hours it took to acquire all of the imaging data. I started by assembling all of the submosaics, then warping them so that they aligned with one another. This process didn't require too much warping, although it was getting more difficult by the later mosaics. The image resolution is stopped down to the resolution of the first submosaic on Ganymede's limb, and I need to check the ephemerides to calculate what that resolution was. https://www.flickr.com/photos/132160802@N06/albums/72157653881252815 so you can view them all at full resolution - the later mosaics appear to have 2-3x the image resolution.
There are a couple other images that didn't fit neatly into this mosaic. There was a UVIS drift sequence, for which ISS rode along to take support imaging. I've tracked down the locations of these frames and written a short description of the terrain in the FOV.
https://flic.kr/p/GCPbfd
Finally, as Voyager 2 began to recede from Ganymede it looked back and took an 11-frame mosaic of the south pole, which is on the terminator about halfway up the image.
https://flic.kr/p/HyCeei
I really need to figure out how to do better geometric control on these images, because it'd be great to try my hand at colorizing these
WOW! That blew up to a much larger size than I expected.
Awesome mosaics. The huge global mosaic is probably a bit distorted though but is a great overview of Ganymede's anti-Jupiter hemisphere. It's easy to see from these mosaics that the Voyager 2 Ganymede coverage is really good and the data quality is much higher than in the Voyager 1 data set (in particular there are no smeared images). The only 'missing' thing is really hi-res images - Voyager 2 got no closer to Ganymede than about 60,000 km, corresponding to a resolution of 600 m/pixel.
Here is a new 4000x3800 pixel color mosaic of a large area around Osiris from Voyager 2 images:
Stunning Bjorn! Can't believe this imagery came from a TV camera!
(staff team, sorry if this may be considered necroposting)
is there any Callisto DEMs using the stereo imagery?
I know there is stereo imagery bc of fig 5 in this short paper
https://www.hou.usra.edu/meetings/lpsc2021/pdf/2228.pdf
but i can't seem to find any Dem maps or dem chunks (i can use chunks to compile a global dem map with the available data like i did with triton's dem)
The paper mentions it's 'PC DEM' where PC == photoclinometric == shape-from-shading.
Incredibly interesting paper on the ArXiv regarding the existence of a giant impact palimpsest on Ganymede.
https://arxiv.org/ftp/arxiv/papers/2205/2205.05221.pdf
Seems rather convincing! Confirmation to follow with JUICE and the Clipper.
P
Here is Voyager 1's Ganymede approach -
Full video here, better quality - https://www.youtube.com/watch?v=q8fp5Tku1Dc
Made with PyVoyager, which I am in the process of de-mothballing... I'm trying to get it ready so people can contribute manual alignments, if interested - https://github.com/bburns/PyVoyager.
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