Here's a quick'n'dirty sequence of wide-angle frames acquired around Cassini's recent ring plane crossing. I've reduced the size to 50% to make the GIF more manageable, the full sized sequence is a tad over 5 megabytes.



Cassini was moving north so the near side of the rings moves down here. Things to note in the movie:
1. the near side is noticeably brighter than the far side, likely due to saturnshine.
2. the Cassini gap becomes brighter at low inclinations, both the lit and unlit sides.
3. there's a quick, dark spoke at the beginning of the sequence visible. It's visible in the 2-4th frames

There's a bit of static hot pixels I haven't removed yet. Not very visible in the reduced resolution but noticeable in the full resolution. There are also a few moons running around, either Mimas or Enceladus and perhaps Prometheus/Pandora.

Hvala lijepa for sharing this gif

Stunning - I hadn't realised just how dramatic the illumination change would be as the viewpoint moves from one side of the rings to the other.

To be honest, you can't directly compare the bightnesses of the lit and unlit sides from this movie. Raw histogram stretching comes into play here -- the dark side is well... darker than the lit more than is shown here, but I guess not by much (judging by F ring's appearance).

Which moon or moons are flying by?

I was thinking about putting that together -- glad you beat me to it, ugordan! That is totally awesome.

I played with the view on space.jpl.nasa.gov and I think it's Enceladus that crosses the view while Cassini's below the ring plane (on the sunlit side), and Mimas that crosses while Cassini's above the ring plane (on the shadowed side).

--Emily

Congratulations Ugordan for a fantastic product and thank you for all your hard work. You've really helped to make these Cassini images "come alive."

Now, Dan, you really give me too much credit! It was a simple case of downloading the raws and shoving them into an animation. No magic or advanced processing!

As usual, Gordan, nice work! Keep those Cassini image products comin'!

The rings appear *much* darker on the unlit side. The difference is even greater than this sequence shows, at least at low phase angles where the lit side appears much brigher than it does at high phase angles. I may post calibrated PDS images sometime in the next several days showing this.

Very nice sequence of images.

Wow, there are actually a pile of moons in this animation: Enceladus and Mimas are the big ones, but Janus, Epimetheus, Pandora, and Prometheus all make an appearance. I made an annotated version (click to animate). According to the Saturn viewer tools at the PDS rings node, Calypso should actually also be in the field of view late in the animation (after the small moons disappear but before Mimas appears), but I couldn't find it.

Click to view attachment

--Emily

Emily you rock!

Here's another short movie, Atlas moving towards Saturn's shadow. Nothing spectacular.


Full res can be found here (4.5 MB).

Great work Ugordan! I've been looking at what you do a lot and your collection is awesome. Especially your work with the calibrated data.

Being a Marsaholic myself I haven't played a lot with imagery from the Cassini mission, but here's my first ever! -don't ask about the colors (just a bit of messing around )



Could anyone tell me what Moon is visible in the top part of the image?
(the filename still has the raw image number in it)

Nico

The filenames don't really help much; they're autogenerated and unlike the MER image fileneames have nothing to do with the spacecraft clock time.

The kludgy way that I figure out which moons are in an image is to begin with the limited information in the caption, which pretty much just tells you the date the image was taken. Then I go to the Saturn Viewer at the PDS rings node, and I plug in 12:00 on the date, usually pick something like 5 fields of view of the wide-angle or narrow-angle camera (if it is a ringmoon, I look wider, because those little things move faster), select a target that will help me find the object (in this case I'd probably pick a ring ansa), and check the result. Then I play with the time, shifting forward or backward by an hour or so, to try to see if I can spot the moon moving through the field of view. In this case, the moon is beyond the F ring so it's most likely Janus or Epimetheus.

--Emily

Thanks Emily I figured the number is indeed not containing time but I haven't used the Saturn viewer before. I'm going to check it out, hopefully there's a search function to look-up a raw-image number?

Nico

I'm afraid not. As far as I know there is no useful information at all in the raw image number. They are not even sequential. They will be sequential for some number of images, then there will be a jump forward or backward in the sequence. My suspicion is that their numbering has to do with when the images hit the ground -- higher priority images may land first, so they may arrive out of sequence. But I don't know for sure. I've never heard of a look-up tool relating the raw image number to any other kind of information on the image. (I would love to find out about such a thing!)

--Emily

Back in the day, Joe Knapp used the known image FEI ids (whatever that is) and using spice kernels he managed to reconstruct the time and target. This required up-to-date kernels and he said a while ago he was just too busy to keep this hobby up. So we're basically left with target distance from the raw page -- you can iteratively guess the time when the image was taken using Solar System Simulator to get distances to targets of interest. Unfortunately, the latter only includes the major moons so Saturn Viewer is the only option I guess.

No search function indeed I've found the sequence again though and saved that page. Playing with the Saturn viewer is going to take 'some' guessing I found out. I got Enceladus in the diagram a few times -but I'll let you know when I get the hang of it

Nico

Not exactly a plane crossing animation, but it does have rings in it so I thought I'd post it here. It's that nice Janus & Titan mutual event animation that was taken several months ago, but I don't recall CICLOPS releasing it.

Composed of 10 frames from the PDS. Caution: large file.

Surreal...what an amazing place, what a viewpoint! Thanks, Ugordan!

very nice. Titan looks absolutely enormous in it! Larger than the diameter of the rings....

That was certainly worth waiting for. Awesome GIF Gordan!

Thanks. Since this is turning into a sort of movie thread, here's a true color Hyperion rotation movie taken a year ago:

Made from 14 sets of 3-color frames spanning 12 hours. The time interval isn't constant, two snapshots were taken closely together and then a larger gap inbetween, causing the movie to appear somewhat jumpy. Magnified 2x.
Note the gradual darkening as phase angle increases from 28 to 56 degrees.

There's also a movie with only 7 frames, but the time interval is more constant.

Fantastic animations guys!
In particular, the Janus+Titan+rings is breathtaking...

Yes...that one is really something. You can easily imagine looking out the porthole & seeing that as the cruiser decelerates into orbit, seatbelts fastened, with your carry-on luggage stowed...

I just have to join in the applause for that Titan and rings animation. Was it really done here first? I can hardly believe they took those shots and never strung them together. Extraordinary! Well done. BTW ugordan I really like your Iapetus one too.

There's a huge ring movie on the raw page, a total of 254 frames. This makes it I think the largest ring movie Cassini ever did. I've assembled all the raw frames into a Quicktime movie (3.1 MB). I used Registax to register the frames as they jump around a lot, it's still a little jumpy, but I couldn't make it any better. First time I used Registax for this purpose.

At 12 fps the movie runs over 21 seconds and features Prometheus, Pandora, Pan, Atlas, Janus, Epimetheus and even tiny Daphnis is detectable at 2 seconds into the movie. Other than that, ring clumps, various density waves and the peculiar elliptical A ring edge are noticeable. I don't know the exact time intervals between frames, but they appear to be more or less constant throughout the movie. It's probably something like 1 or 2 minutes inbetween. I'd have posted a DivX version as well, but it appears to destroy all the small scale detail compared to the superior H.264 codec.

EDIT: There's an improved version of the movie below.

Wow thanks for that Gordan!

Indeed...that is extremely cool, Gordan! Gonna share this with my co-workers tomorrow, they'll love it!

Very impressive movie showing the F ring dynamics with its shepherding moons. I believe I also see Pan and some other dynamics within the Encke division, as well as some changes within the Keeler gap.

Yes, there are definitely waves visible in the gaps, something that is somewhat lost in the movie due to compression, but is readily apparent in the raws. The Encke gap disturbance persists for a long time and at one moment, due to the frame timing it appears something is moving backwards at the outer edge of the gap.

EDIT: Here's an updated version, this one is less shaky - I ran it through Registax one more time. It's also slightly less compressed.

http://www.fileden.com/files/2007/9/14/143...ing_movie_2.mov

I think I saw Daphnis in the Keeler gap too. It zips by about the the same time as as Atlas,and Prometheus are at 10 o'clock.

You should be seriously proud of that movie, it's one of the most professional "products" ever to appear on UMSF I think. Can't wait to show it at my next astro society meeting.

I wouldn't go that far. It's a fairly low-end product that was basically just registered frames with minor level tweaks. Not even cosmic noise was cleaned up (you do THAT for over 250 frames!).
Thanks for the kind words, though!

That is way cool.

I really like how you can see the gravity waves in the outer ring right beside the moon as it whooshes by on the inside. (I used the cursor to toggle back and forth)

Nice job!

-Mike

Nah...Stu's right, you're too modest, Gordan. This is an overwhelmingly enlightening & valuable product, professional-grade beyond dispute; thank you!!!

Again, not a ring plane crossing or anything, but a rather nice movie of Mimas rising behind Saturn's limb:



Clicking the above image will bring up a full res GIF movie (caution, 2.3 megabytes) consisting of 10 frames. The frames were originally clear filter frames colorized using a single RGB set available. Two bright stars are also visible in the movie. The dent at Mimas' 12 o'clock is Herchel crater.

Enjoy!

*thunk*

<gets back on chair>

Whoa!

That loud "thunk" was my jaw hitting the floor. Good GRIEF!!! Thanks gordan, that's a stunner. "Mimas-rise"... unbelievable...

Thanks, guys. I deliberately rotated the movie so north is to the right so the "Mimas-rise" evoked a scene of our own Moon rising through our refractive atmosphere as seen from space and to a lesser extent evocative of Apollo-esque scenes of the Earth rising above the much darker moonscape.

You can really see how much near-zero phase brightens even low albedo ice compared to Saturn's atmosphere. Remember this is Mimas, Enceladus would be even brighter! (See for example the second image in this post). It's kind of sad the low phase at the same time killed any topography that would be otherwise visible on Mimas. Mimas actually looks more like Enceladus here, minus the dent at the top.

Brilliant, Gordan!

From an artistic point of view the question of preferred orientation is particularly interesting in the Saturn system, where the ring plane and the surface of the planet provide alternative 'horizontals' for the landscape-conditioned human eye to rest upon. The decision to go for either - or neither - is all part of the art of image making. There's no doubt you've done it superbly here.

Wow!

That's truly awesome!

[And there's a cool little ring bloop that comes in at the end]

Very, very nice work!

-Mike

WOW, Gordan! It's almost like being there! Thanks!!!!

Ditto wow!

Gordan, this movie is killing!
I think such sequence could be taken from a new release of "2001: a Space Odissey" movie, surely Sir Arthur Clarke would appreciate (and Stanley Kubrik too, if he come back to life!).
You did a really great work and thanks to Cassini team for taking such sequence!

That is an incredible sequence. Great work!

Thanks. The sequence itself was taken on 2007-10-26 starting at something like 17:47 UTC and captured 1 frame every half a minute (rough estimate). According to Celestia the two stars are HD 90155 (upper one, mag 6.60) and HD 90125 (lower left, mag 6.32). It also appears the wide angle shot of Mimas, Atlas, Titan and Epimetheus shown here immediately postdates this sequence.

I'll add my congratulations- very cool, ugordan!

This movie nicely illustrates how Mimas is not in Saturn's ring plane- the position of the rings shows that Cassini was on the right-hand-side of the ring plane (in this orientation), but Mimas, behind Saturn, is on the left-hand-side of the rings.