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Posted by: jasedm Oct 3 2007, 05:10 PM

There are some great mid-range and far-out icy moon and rock encounters in the offing over the next month and a half...
Cassini has a break from skimming Titan's cloud-tops and comes within some fairly useful ranges of various other moons.
I don't know how many of the following will be targeted for imagery (Ciclops looking ahead page hints at several), but I'm guessing Hyperion and Enceladus, and hoping for Prometheus and Pan.
The distances I have are from various averaged sources and may be up to 10% out to allow for trajectory changes:

21st Oct - Hyperion 117,000km
24th Oct - Helene 36,000km
24th Oct - Prometheus 105,000km
24th Oct - Janus 150,000km
16th Nov - Rhea 80,000km (everyone's favourite!)
17th Nov - Pan 96,000km
17th Nov - Calypso 94,000km
17th Nov - Enceladus 120,000km
17th Nov - Pandora 88,000km
17th Nov - Epimetheus 95,000km

Echoing sentiments elsewhere on the forum, many congratulations to the Cassini team thus far.

Posted by: scalbers Oct 7 2007, 07:37 PM

Here's a try at a Celestia movie for Enceladus Nov 17 that suggests a potential to fill in some map details. After the closest approach there is a period at low phase angles where Enceladus rotates around at a distance of about 250000km.  enceladus2.avi ( 868.5K ) : 452


I hope to use some of the intervening time to iron out a few wrinkles in my triaxial ellipsoid remapping.

EDIT 10/08/2007 2130 UTC: Movie replaced with corrected longitudes (I hope).

Posted by: alan Oct 7 2007, 09:03 PM

Why does Enceladus go dark half way through? Is it passing through Saturn's shadow?

Posted by: scalbers Oct 7 2007, 09:11 PM

Yes alan, there is an eclipse going on during 11/17.

Another note is that the subpoint is a bit more southerly for this flyby compared with the one from the past week, so despite the farther distance it should be somewhat favorable for mapping of the interesting mid-southerly latitude dark markings. These are good to get while the southern summer is still in progress.

Posted by: Holder of the Two Leashes Oct 22 2007, 04:19 PM

A new sequence of Hyperion images are starting to come up on raw images.

Here is one http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feiImageID=129975.

Posted by: jasedm Oct 23 2007, 06:52 PM

Much anticipation on my part for this Hyperion mini-sequence - I think this may be the closest we get to 'old spongy' in the remainder of the mission (primary and extended) and the mission planners seem to be giving it a fairly high priority....
I'm also REALLY looking forward to Cassini making some better-than-voyager observations of Prometheus (closest so far is about 380,000K I believe). It's the only pre-2004 named moon not to have better coverage than voyager achieved.
I'm convinced that this little 'coalescence of snowballs' holds some surprises for us. It seems to be the most intimately ring-associated moon, and the accretion processes are practically visible from frame to frame, when it dips into the inner reaches of the F-ring!!
I suspect it will be very different to Atlas, with it's equatorial concretions when we finally get to see it up close.

Posted by: volcanopele Oct 23 2007, 07:22 PM

There will be no observations of Prometheus near C/A. The phase angle at time is very high at the time of closest approach and there is a Saturn near-eclipse observation at the time.

Posted by: jasedm Oct 23 2007, 07:48 PM

Yes, it's a shame VP but I live in hope for a close-up or two in the forseeable future....

Posted by: OWW Oct 25 2007, 02:24 PM

In case no one noticed... the Hyperion images are in:

http://saturn.jpl.nasa.gov/multimedia/images/raw/casJPGFullS34/N00094340.jpg

Posted by: CAP-Team Oct 25 2007, 03:17 PM

I tried to create a "color" image from the UV3/GRN/IR1 images..

Hyperion looks kind a gray

Posted by: ugordan Oct 26 2007, 10:18 PM

Assorted moon shots, stretched color:
http://i108.photobucket.com/albums/n15/ugordan/Mimas_rev51.jpg http://i108.photobucket.com/albums/n15/ugordan/enceladus_rev51.jpg http://i108.photobucket.com/albums/n15/ugordan/tethys_rev51.jpg http://i108.photobucket.com/albums/n15/ugordan/dione_rev51.jpg
Mimas, Enceladus, Tethys, Dione

Posted by: jasedm Oct 31 2007, 04:37 PM

It's amazing how quickly one takes for granted a spacecraft with a decent camera in orbit around Saturn....
I remember as a teenager, poring over the Voyager images and itching to know what lay just past the terminator or over the horizon on some of these icy moons. I visited my local library and photocopied every available Voyager image (pretty slim pickings in most of the astronomy publications back then)
The shots Ugordan has posted above although fairly distant, show territory East of Sabinus on Dione, and Penelope on Tethys that I would have paid a lot of money back then to have seen!
The USGS maps that I have of the various icy moons now look quite quaint and dated compared to the Steve Albers (and others) versions now available - It's a great privilege to be along for the ride as these new territories are opened up to scrutiny, and to be party to some of the informed planetary geology discussions on this board.

Posted by: tedstryk Oct 31 2007, 07:47 PM

They really do seem like different worlds. This is partly due to the fact that many of the Voyager images were quite distant and blown up to a ridiculous size. For example here is the best low-phase, complete global view of Dione, showing the "streaky" areas, shown at its original size. I have cleaned it up significantly. However, I have seen this picture in a book blown up to fill a 16x20 page, and without all the black area around it I have put here. Such grossly over-enlarged images give these moons a fuzzy, amorphous feel that Cassini has wiped away.

Posted by: jasedm Nov 8 2007, 08:39 AM

The 'looking ahead' section on the ciclops page has been updated for the next revolution - imaging of Enceladus to scrutinise the polar plumes, Rhea from quite a distance, and some shots too of Anthe (I don't imagine these will be more than half a dozen or so pixels across at the most) Also, Saturn eclipses the sun in one of the sequences

Posted by: ugordan Nov 18 2007, 09:07 PM

When are the new images scheduled to appear? Not being unpatient here, just feeling slightly uneasy due to the fact no new images were posted since Nov 11.

Posted by: jasedm Nov 20 2007, 11:04 AM

I've been wondering about this myself Ugordan. There's nothing in the recent 'significant events' pages to explain.
It's easy to become accustomed to the excellent and timely posting of the raws that one starts to take the service for granted. When the raws page first appeared, it had some teething problems and delays as you'd expect (just after orbit insertion) Since then it's been exemplary.
I must admit I live with a slight and constant fear of something catastrophic happening to Cassini out there to cut short the rest of the mission, and things like this are a worry.
However I'm sure we'd have heard by now if Cassini had been incorporated into a hitherto unknown moon .
I believe it's the scariest day of the year for American turkeys on Thursday, so we may not know for a few more days yet....

Posted by: ugordan Nov 20 2007, 05:37 PM

You can breathe a sigh of relief, new images are coming up on the raw site. Looks like everything's fine with the s/c, but the raw site had a hiccup - it's only just now catching up to the downlinked imagery from Nov 10.

Posted by: volcanopele Nov 20 2007, 05:42 PM

Actually, I would think that Thanksgiving is one of the happier days for turkeys: if they made it that far alive, they won't be food for the holidays. You may even get pardoned...

Yeah, T37 images are down. Move along. Nothing to see here

Posted by: OWW Nov 20 2007, 06:30 PM

You got that right. Looks like Cassini missed Enceladus. Only black images of empty space.

Posted by: ugordan Nov 20 2007, 06:37 PM

http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feiImageID=136040

Posted by: helvick Nov 20 2007, 06:54 PM

Wow - that's gotta be very high on the list for shot of the year.

Posted by: volcanopele Nov 20 2007, 06:54 PM

LOL yeah that's my desktop image of the day

Posted by: jasedm Nov 20 2007, 07:18 PM

Oh it's all happening now - nothing for a couple of weeks and then Bang!
Fantastic image of Mimas and the F ring! - they kept that one quiet!!
Nice to see some opnavs of Epimetheus too - he gets his closeup in the next orbit. Very high phase angle at closest approach but less than 10,000km - should be a fantastic flyby.
Anybody identified the Anthe shots yet???

Posted by: volcanopele Nov 20 2007, 07:31 PM

LOL, it's not that we wanted to keep that quiet. That image is actually an opnav image and unfortunately my source for what images are coming up do not include the opnavs. Even though they use the camera system, the Imaging team doesn't plan them, the Navigation team does.

As far as Anthe goes, I *think* this is one of them: http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feiImageID=136016

Posted by: ugordan Nov 20 2007, 07:39 PM

Flying by Rhea: http://www.fileden.com/files/2007/9/14/1431389/Rhea_200711.gif (1.8 megabyte).

There's a nice shot of Pan and the gravitational wakes, too: http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feiImageID=135823

Posted by: tedstryk Nov 20 2007, 08:34 PM

Thanks! That seems to show a similar angle to the Voyager crescent sequence, but with much better resolution.

Here is a quick and dirty comparison. The Voyager shot is a somewhat smaller crescent, but close enough that it has the effect of revealing a relatively well known angle (thanks to the voyager shot) clearly for the first time. Always a neat experience.

Posted by: ugordan Nov 20 2007, 09:00 PM

Wow, that really does looks similar. Sweet stuff, even the colors match up pretty well.

Posted by: jasedm Nov 20 2007, 09:32 PM

Hello Anthe! and welcome to the family!
I think you're right VP - Images N00097699 to N00097701 show the object traversing the NAC FOV. Apparent diameter would seem to match what you'd expect for a ~2km object at this distance. Very cool to be seeing the (barely) resolved disk of an object only known for a few weeks.
For the umpteenth time, hats off to the Cassini team for allowing us all to ride shotgun on this mission.