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Full Version: Rev 126 - Feb 4-22, 2010 - Mimas (main target), Tethys
Unmanned Spaceflight.com > Outer Solar System > Saturn > Cassini Huygens > Cassini's ongoing mission and raw images
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belleraphon1
All

closest look at Mimas ... 30 minutes after periapsis on 02/13/10 at 17:25 UTC

http://ciclops.org/view/6188/Rev126

"Thirty minutes after periapse, ISS will perform a targeted encounter with Saturn's innermost large icy satellite, Mimas. The altitude for this encounter is 9,510 kilometers (5,910 miles) the closest Cassini has ever gotten to this cratered moon. For this encounter, ISS will acquire three mosaics along with another observation where ISS will be riding along with the Composite Infrared Spectrometer (CIRS). ISS' first mosaic of Mimas, GEOLOG001, will start 30 minutes after closest approach when Cassini is 14,800 kilometers (9,200 miles) away from Mimas. GEOLOG001 is a seven-frame, multi-spectral mosaic of the region surrounding the crater Herschel. Herschel, at 130 kilometers (80 miles) across, is the largest impact basin on Mimas, so large that it caused significant amounts of stress on the lithosphere of the small moon and so distinctive that it helped give the satellite the nickname, "The Death Star Moon." These high-resolution observations of the basin will be used to estimate the age of the crater. Scientists will count the number of smaller craters on the basin floor, compared to other regions on Mimas, to set limits on how old the basin can be. The second mosaic, GEOLOG002, will also be a seven-frame, multi-spectral mosaic, this time covering most of the visible surface of Mimas, shown above left. The best resolutions for these two observations will be 87 meters (285 feet) per pixel for GEOLOG001 and 191 meters (626 feet) per pixel GEOLOG002. Next, Cassini will ride-along with a CIRS FP3 temperature map of Mimas' day side, acquiring six narrow-angle-camera images during the scan. Finally, ISS will acquire a full-frame, multispectral observation (GLOCOL001) of Mimas' anti-Saturn hemisphere from a distance of 70,000 kilometers (44,000 miles). Saturn will provide a backdrop for this observation."

Glorious

Craig
volcanopele
Don't forget poor little Calypso.
jasedm
Yes, I'm glad that Calypso is getting a closer inspection on this rev - it'll be interesting to see how subdued the craters are compared to it's sibling Lagrange moon Telesto

This will mean that everything bigger than a kilometre or so within Hyperion's orbit will have been imaged by Cassini from less than 75,000km, except for Pan, Daphnis, Anthe and Methone - quite an achievement in itself.

Really looking forward to Mimas - I wonder if there'll be more visible faulting around Herschel at the higher resolution?
DrShank
waiting in a snowstorm in DC to see if my train will depart on schedule . . .

Just posted some background info, data, and mosaics related to the upcoming Mimas encounter, including a rotating Mimas movie with the latest global mosaic, on my blog. (the movie is too large to upload here)

http://stereomoons.blogspot.com/
http://www.youtube.com/watch?v=CwWBZFIBkr0

enjoy!
belleraphon1
Very Cool Dr. Shank!!

I cannot wait!

Thanks.

Craig
scalbers
Nice to see Dr. Shank's color map update. Here is my latest (in B&W) for comparison:

Click to view attachment
scalbers
"Live" shot via Celestia:

Click to view attachment
scalbers
Here's a little movie...

Click to view attachment

Near closest approach (WAC FOV) at 1713UTC

Click to view attachment

View around 1750UTC - looks more elliptical again

Click to view attachment

"Live" Herschel NAC field of view at 1814UTC

Click to view attachment
peter59
QUOTE (scalbers @ Feb 13 2010, 05:58 PM) *
Latest "live" shot at 1713UTC

Thanks
Hungry4info
Very much looking forward to images!
volcanopele
Just an FYI: the play back earlier was a short one, only running 2 hrs 20 mins. So we only managed to play back some of the data acquired during the periapse period, like the Calypso images and some images acquired of Saturn's haze layers while Cassini was in the planet's shadow. There is another playback period tonight and that one is the normal, 9 hours long. The Mimas data were carried over to that one.
ugordan
Eclipse view from Feb 13, WAC RGB:
Click to view attachment

Hmm, the more I look at this, the more it seems I've got it upside down. The rings look as if it's their unlit side, but their shadow should definitely not fall onto Saturn's northern hemisphere. Perhaps it's just the low illumination making this high phase view look unlit. Hence Cassini being above the ring plane and looking "down" onto the rings.

Edit #2: Yep, it's upside down. The parallax motion is only consistent with Cassini orbiting prograde if the image is rotated. Here's the correct orientation and some brightness/saturation enhancement.
Click to view attachment
Astro0
Wow, Calypso looks like a neat little place smile.gif
Quick animation.
Click to view attachment
Adam Hurcewicz
I stack to color image smile.gif from this:

N00151479 ( R )
N00151479 ( G )
N00151478 ( B )
Ian R
Here's my version of the Calypso flyby:

http://www.flickr.com/photos/10795027@N08/...548039/sizes/o/
ugordan
Nice work, Ian!

Reminds me of Telesto, but the surface doesn't appear to be as smooth.
jasedm
Some pretty smooth areas at this resolution - it reminds me of Tempel 1 - infilled small craters, and large areas of very smooth terrain.
Floyd
Adam--Welcome to UMSF! Nice color image--very crisp. I look forward to seeing your work on more images in the future.
nprev
Seems like almost every 'rock' in the Saturn system is pretty much covered with external 'snow'. (Sorry for all the 'quotes'! smile.gif) I assume most if not all of this is coming from Enceladus & not the rings; wonder if this tells us anything about the duration of Enceladus' eruptive activity.
Floyd
This look at Calypso was from 21,257 km at closest approach--we get 5 more looks from under 50,000 km:
Aug 13 2010 22,867 km phase 87 deg inbound
Sep 23 2010 39,359 km phase 87 deg outbound
Mar 10 2012 43,307 km phase 62 deg outbound
Apr 14 2012 49,523 km phase 61 deg inbound
Sep 30 2015 36,251 km phase 72 deg inbound

volcanopele or anyone who can answer:
For non targeted flybys listed on SM-7_all.txt, what percent will actually be used for imaging? I know sometimes other activities have higher priorities. My question is not for every (nt) on the list, but in general and for the 5 encounters listed above.

Edit: Wow these images get out fast. Wikipedia entry on Calypso is updated with yesterday's image.
scalbers
While we're waiting for Mimas images here are some improved movies made using Celestia. The wider angle one is almost the WAC field of view and the other one is about the NAC FOV. In the NAC one we can see Saturn and some other moons go by as Mimas recedes.

http://www.flickr.com/photos/47608252@N08/
Ian R
QUOTE (ugordan @ Feb 14 2010, 01:31 PM) *
Nice work, Ian!


Thanks Gordan cool.gif - I've uploaded a more 'viewer-friendly' version to YouTube:

http://www.youtube.com/watch?v=OGbx7_GHXfw

scalbers
Nice 3D effect with Calypso, almost looks like we're holding one of those cardboard models and spinning it around smile.gif
ElkGroveDan
I guess I didn't get up early enough. Here's my belated version of calypso
Greg Hullender
QUOTE (Ian R @ Feb 14 2010, 08:48 AM) *
I've uploaded a more 'viewer-friendly' version to YouTube:

Why does it wobble back and forth repeatedly? Is it just showing the same sequence three or four times?

--Greg
Ian R
Yes, it's the same sequence of images bouncing forwards and backwards; repeated four times. I prefer this sort of presentation as it allows (in my opinion, anyway) for a better appreciation of the three-dimensional shape of the moon, and is less jarring than a standard 'forward-only' animation.
Explorer1
Is it just my imagination, or are there thin parallel lines near the right side limb? What could be causing them?
volcanopele
Nope, you're not crazy. I was starting to wonder when someone bring up the neatest thing about Calypso...
Explorer1
QUOTE (volcanopele @ Feb 14 2010, 12:51 PM) *
Nope, you're not crazy. I was starting to wonder when someone bring up the neatest thing about Calypso...


I guess over half a decade of lurking on this forum has honed my observation skills. wink.gif
elakdawalla
Coolness! And good eyes, Explorer1. I noticed those too smile.gif Given that there's evidence for landsliding-type motion on other small worlds like Itokawa and Eros, I'd speculate wildly that's what we're looking at -- some kind of flow of the surface fluff toward local gravity lows, possibly induced by the vibration from small impacts.

Neat neat neat!

Emily
Explorer1
So when is the Mimas image down-link? This is the best view we'll get of Mimas for a long time to come, right? The suspense is just.... ugh! wacko.gif
imipak
I know; isn't it brilliant? Anticipation's half the fun! Every encounter is like a mini launch, orbit insertion or EDL smile.gif
Stu
QUOTE (Explorer1 @ Feb 14 2010, 10:55 PM) *
The suspense is just.... ugh! wacko.gif


(Obi Wan Kenobi voice on) Patience, young Explorer... impatience leads to anger, anger leads to hate, hate leads to... well, not a very nice place at all... (voice off)

Seriously, just enjoy it. We're spoiled rotten nowadays, and checking again and again to see if new images are up is all part of the excitement. smile.gif
volcanopele
Tomorrow 5:30am MST/12:30pm UTC, +/- 2 hours
vikingmars
smile.gif I just like very much this oval moon (Cassini pic from Sept 2009). Enjoy ! smile.gif
Click to view attachment
Astro0
Mimas...quick stitch ohmy.gif
Click to view attachment
ugordan
QUOTE (tedstryk @ Feb 15 2010, 12:41 PM) *

Check out that darkening creeping up the crater walls! It's looks like sediment left over from liquid evaporation.
peter59
Damn, the best picture is a bit overexposed. mad.gif
http://saturn.jpl.nasa.gov/multimedia/imag...7/N00151520.jpg
ugordan
QUOTE (peter59 @ Feb 15 2010, 01:18 PM) *
Damn, the best picture is a bit overexposed. mad.gif

I don't think it's overexposed. More looks like the effect of very low phase on brightness and contrast. Also, who knows what the raw contrast stretch did here.
Bjorn Jonsson
QUOTE (tedstryk @ Feb 15 2010, 11:41 AM) *


The last one is obviously Herschel. Very few craters on Herschel's floor and all of them are small. I expected to see some landslides on the crater rim's inside but there are none (or at least no big ones). One thing to keep in mind: The images are heavily contrast stretched because Mimas more than fills the field of view - no black space is visible. So I suspect that what's black in this image really isn't in black (in shadow).

There are some WA context images, for example this one:
http://saturn.jpl.nasa.gov/photos/raw/rawi...?imageID=213720

A nice NA global image:
http://saturn.jpl.nasa.gov/photos/raw/rawi...?imageID=213675

A closeup of Herschel with some black space visible - the contrast stretch doesn't mess things up completely in that case:
http://saturn.jpl.nasa.gov/photos/raw/rawi...?imageID=213654

Mimas' rough and uneven limb:
http://saturn.jpl.nasa.gov/photos/raw/rawi...?imageID=213606

Should be plenty of images for a nice stereo-derived DEM of Herschel smile.gif. The fact that the subsolar point is close to Herschel might be a problem though.
volcanopele
QUOTE (Stu @ Feb 15 2010, 05:19 AM) *

Here is an even better version laugh.gif

http://saturn.jpl.nasa.gov/photos/raw/rawi...?imageID=213678
Bjorn Jonsson
QUOTE (ugordan @ Feb 15 2010, 12:16 PM) *
Check out that darkening creeping up the crater walls! It's looks like sediment left over from liquid evaporation.

The image is heavily contrast stretched since no black space is visible so I think the darkening is only slightly darker than the stuff above it. Still very interesting.

EDIT: From the image someone said was overexposed I now see the contrast is higher than I expected (I'm looking at the images as I type wink.gif).
Stu
QUOTE (peter59 @ Feb 15 2010, 12:18 PM) *
Damn, the best picture is a bit overexposed. mad.gif


... or, to put it another way...

WOOHOO!!!! New pictures of Mimas! And we can drool over them just a day or so after they were taken!!! How lucky are we?!?!?!?

rolleyes.gif

Stunning pics, Cassini just keeps delivering, doesn't she? smile.gif
Floyd
Wow, what a great set of images, including Epimetheus and Janus playing rocks. Very exciting to be on the Cassini site as the boxes with red X's turn to impossibly great images.
ugordan
QUOTE (Bjorn Jonsson @ Feb 15 2010, 01:30 PM) *
EDIT: From the image someone said was overexposed I now see the contrast is higher than I expected (I'm looking at the images as I type wink.gif).

I'm guessing low albedo variations show up so clearly because of the low phase angle here.
charborob
QUOTE (peter59 @ Feb 15 2010, 07:18 AM) *
Damn, the best picture is a bit overexposed. mad.gif
http://saturn.jpl.nasa.gov/multimedia/imag...7/N00151520.jpg

Modifying levels and curves on this image in Pshop, I get this:
Click to view attachment
There seems to be ridges (outcrops?) on the central peak of Herschel.
volcanopele
Four of the images from the encounter are highlighted on the CICLOPS website:

http://ciclops.org/view_event/128/Mimas_Re...yby_Raw_Preview
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