Ganymede is a planet in its own right. An iron core and silicate mantle topped by an icy crust which is partly fluid. An.internal heat source which generates a magnetic field. The surface exhibits tectonic activity possibly still ongoing. I wonder the source of its watery/ oxygen atmosphere whether is solely due to a collisional source and not a result of this tectonic acitivity?!

here, made a map from that image

(got blurry when i used the transform tool in gimp when i was moving the features into place)

Allow me to congratulate you on executing and capturing what, by all accounts appears to be a great dataset, if the green filter product alone is to be any indication. Even that quicklook looks awesome, absolutely the best coverage of Ganymede we got since Galileo.

Heck, even that Stellar Reference Unit image completely blows away any post-Galileo imagery.

Wow! I love the first release, of the green-filter image. Ganymede is a beautiful world and these images certainly capture a representative sample of the major terrain types, from ancient plains to grooved terrain to bright crater rays. I can't wait for the results from the other instruments observing this same terrain!

I for one am low-key excited about the SRU image. One of the concerns I had for the Io flybys was to what degree JunoCAM could do Jupiter-shine imaging. But from this SRU image, there is no reason I can see (except that Jupiter-shine will be stronger during the Io encounters) for the SRU not to do great Jupiter-shine imaging along with hotspot mapping.

For this SRU image itself, that that south is up in the release version, so I've attached just a flipped version:

Click to view attachment

For the curious, center lat and long is approximately 19N, 81W within Xibalba Sulcus. The crater at upper right is Leomadon. The bright streak at center right is possibly a distal ray from Tros (the prominent ray crater in the JunoCAM release)

And the JunoCAM image is amazing. Very crisp, very little noise... Just amazing.

And I want to echo the congratulations posted earlier, the green filtered image looks great. I am actually slightly (and pleasantly) surprised by how quickly this first image appeared. I have to admit though that I am probably more interested in seeing the results from the instruments (MWR etc.) that are very different from the Galileo and Voyager instruments.

Voyager 1 obtained fairly good images of some of this terrain but some of its images of e.g. Tros are smeared due to radiation (scan platform was moving when the camera shutter was open). This makes the JunoCam images more interesting.

Rough idea of the timing of the SRU image. As you can see the predict kernel is a bit off, so it was actually take shortly afterward, but still gives you an idea.

Click to view attachment

Congratulations to all those involved in the JUNO mission. These first images are just amazing ! I did not expect the JunoCam pics to be so sharp and even did not know that the SRU would be able to take such Jupiter-shine images. The low Sun angle helps and we see Tros as never before. I agree with Bjorn, I'm sure that we will get many surprises once the data from the other instruments will be analyzed (internal structure, global ocean, surface composition, thin atmosphere, magnetic field,...). What a world ! The JUNO extended mission is really a new mission. This is only the beginning... and I'm already bluffed !!

BTW, is this a new caldera-like feature, in the Northern part of the SRU image ?

yeah, the sharpness is absolutely outstanding

i was even able to make a 4k map from the junocam image
https://cdn.discordapp.com/attachments/7537...e_juno_2021.png

if i could, i probably could make a 8k map from the image

BTW, there is a 1625x2524 TIFF version of the green-only image at https://photojournal.jpl.nasa.gov/catalog/PIA24681

I'd honestly hold off. Within the next day or so I'm sure we'll have the full raw image and it can be map-projected in something like ISIS without the quick look image seams and with limb fitting/geometric control.

a full resolution processed image when it comes would be better than raw images, because raw images tend to have some artifacts

--edited--

you will then have to wait until they are on PDS

What a great camera !

The SRU image is nice. I had checked the geometry in Cosmographia, wondering if there would be enough Jupiter-shine to acquire a JunoCam image, but it seemed like only a crescent of Jupiter was illuminated, so I thought there wouldn't be enough light. However, seeing the SRU images make me wonder if a long-TDI JunoCam exposure would have picked up some detail.

The reconstructed c-kernel is now available so let me update the Cosmographia view of the SRU frame. Somethings not quite right... makes me wonder if the FOV for the SRU in the instrument kernel (juno_struct_v02.ti) is correct. It lists it as having a FOV of 16°x16°.

EDIT: found the paper describing the SRUs. Yep, intstrument kernel is wrong according to Becker et al. 2017. Given what I'm seeing, I trust the paper. Will update the figure in a few minutes.

EDIT2: Updated SRU preview graphic with updated FOV. Still looks like the real image is a bit to the east of where this shows...
Click to view attachment

Pixel scale comes out to 618 m/pixel.

I am impressed with the images.

There's a proposed mission concept for a Juno-like orbiter at Uranus (QUEST). The focus is the planet's interior and magnetosphere (like Juno before this extended mission). The proposers pointed out their JunoCam-like camera could also image the moons during flybys, and I mentally poo-pooed it. Now, I'm thinking that it would do better geologic science than I thought. And if a Juno-like mission had a goal for satellite imaging, it could carry a medium-resolution camera.

Can you give me title or link. I don't think I have that in my collection.

I didn't expect this to happen until the arrival of JUICE in 2029 but some of the current images/maps of Ganymede seem to have become very obviously outdated today.

Here is a very quick-and-dirty montage comparing what I think is the best pre-Juno image of Tros to the new image - the improvement is obvious:

Click to view attachment

The image at left is a lightly processed version of Voyager 1 image C1640422 at its original size. As far as I know this is the best image of Tros before Juno. There is a later image at theoretically higher resolution but it is badly smeared. There are also some images with Tros closer to the limb; there the emission angle is too high.

Galileo obtained only low resolution images of Tros.

Using the green-frame image and doing a little old-fashioned measurement, it is stretched about 8.2% in the downtick direction and can be circularized by multiplying that dimension by 0.92. I believe that what others derive by other means should inevitably agree with that.

The Juno Radiation Monitoring (RM) Investigation
Becker et al.
Space Sci Rev (2017) 213:507–545
https://doi.org/10.1007/s11214-017-0345-9

okay, i'll hold of on an 8k map

Bjorn, Juno did an outstanding job of getting the full details of Tros and other blurry areas that Juno got sharp images of
"I didn't expect this to happen until the arrival of JUICE in 2029 but some of the current images/maps of Ganymede seem to have become very obviously outdated today."
yup, a large part of what Juno imaged was a bit blurred in already existing maps

Thanks. Grumble paywall grumble.
Just a bit of the downside of being an unaffiliated unfunded community scientist.
At least the Mars papers I've looked for have been open-access.

Ganymede images now on missionjuno.

Along with a number of PJ34 Jupiter images.

Wow! The Ganymede image processing already looks great on missionjuno. The brightest areas are running closer to coffee-colored than the whites that I've seen from, e.g, Voyager and Galileo. It's one of the most beautiful worlds in the solar system, if I may use technical terminology.

Very rough cut:

Click to view attachment

Looks like I need to make a control point network... hooray!

My humble offering of a re-projected red-filtered frame:
https://www.flickr.com/photos/10795027@N08/51235091798

Wow! Just spectacular. I wasn't aware how many large craters on Ganymede have central pits instead of peaks or peak rings.
Presumably something to do with the gravity/surface composition/relaxation time?
People are going to be pouring over these for weeks.
And that SRU image is a wonder, as others have pointed out, very interesting for future gas and ice giant missions (OT I know)


P

Here is a very quick & preliminary version of image pj34_01 at roughly the original resolution showing Ganymede with the crater Tros prominent below and right of center:

Click to view attachment

Here Juno's altitude above Ganymede's surface was ~1300 km. The image may have some minor geometric inaccuracies that will be corrected if necessary in a later version.

My first cut. Collage of first four Ganymede images. Un-exaggerated color/contrast.
Click through for full-res version.


PJ34 Ganymede Image Collage un-exaggerated color/contrast by bswift, on Flickr

Also, 297 MB 16-bit PNG version now available at https://www.missionjuno.swri.edu/junocam/processing?id=10668

A semi-manual attempt at a color composite:


2021-June-06 by Ian Regan, on Flickr

Impactors hitting Ganymede gain velocity from falling into Jupiter's gravitational field. Because we see little to none of that with Io and Europa, Ganymede is the primary location where we see the results of that.

I usually just lurk here, but these image are so spectacular and so much better than I was expecting, I had to say something. Reminds me of when I first saw Ganymede in 1979. Thanks, Juno!

If this is the 2nd most-boring Galilean, I can't wait to see the less-boring ones.

I almost mistook the wide-field Ganymede image for Earth's moon in a media report on my phone, with its 'Tycho', 'Crisium' and 'Imbrium'.

I have a hard time formalizing what it is about this encounter but it is one of the best and purest example of a "free" flyby that wasn't in a mission's original plan that I can think of. There have been some great flybys of opportunity (like Venus on Galileo's way to Jupiter) and certainly Galileo and Cassini both had endless satellite encounters that weren't specifically planned but were very much like what one expected for an extended mission. This is more like a holiday gift than anything else I can recall, with Gaspra, various Phobos/Deimos encounters and Arrokoth some similar occasions.

antipode: "Wow! Just spectacular. I wasn't aware how many large craters on Ganymede have central pits instead of peaks or peak rings."

After Voyager 1 observed these pit craters in 1979 people pointed out very similar craters on Mars - far from every crater obviously but in some areas there are quite a lot. The inference at the time was that they were related to impacts in an icy crust. I don't know how well that idea has survived subsequent analysis.

Phil

Obviously, I'm a little slow.
Here is a link to my versions of Ganymede at 30 pixels per degree.

OMG those are downright beautiful!!

If Ganymede is this beautiful, Europa & Io are going to be wonderful.


I do hope the Distant look at Europa happens this July.

Thanks Ganymede for finally convincing me to send in an ISIS bug report...

https://astrodiscuss.usgs.gov/t/uncaught-ex...-c-position/702

Ganymede composites of PJ34-1 & PJ34-2:



Ganymede - Perijove 34



Ganymede - Perijove 34

This is my first post here after lurking since 2015

I just wanted to say that the images from this flyby are absolutely stunning!

Just one naive question: is the resolution high enough to make some DEMs ? I think it should be possible between the first two images... or even between JUNO and Voyager 1 images from the same region.

Thank you very much!!! Been waiting for this for a long time. I know I'm not the only one.

Kevin – Wow! Thanks for that. I just shivered.

Regarding DEMs, I don't think that the resolution here can add much to global topographical maps, but the altitudes of features casting shadows can be measured, and that includes a useful diversity of major feature types – grooves and craters.

Nothing short of astonishing - I'm gobsmacked by the resolution and clarity