Rev 102 'looking ahead' now on Ciclops.

http://ciclops.org/view/5470/Rev_102

There is so much in this targeted encounter I just note one highlight.
QUOTE: "RADAR also will observe a set of bright streaks south of Senkyo, previously observed by ISS and VIMS. The VIMS team has hypothesized that these streaks are mountain ranges. RADAR’s observations of these features could prove or disprove this possibility."

Of equal interest to me, however, is this earlier observation (Jan 31st).
QUOTE "Next, ISS will image again Titan’s sub-Saturn hemisphere, this time from a distance of 1.94 million kilometers (1.21 million miles). In addition to looking for clouds, this observation provides an opportunity to image Titan’s largest methane sea, Kraken Mare, albeit at a moderate emission angle."

I'm wondering if this will be an opportunity to use the polarising filters to look for specular reflection of sky light from Kraken Mare, as we discussed here a little while ago:
http://www.unmannedspaceflight.com/index.p...st&p=129761
and
http://www.unmannedspaceflight.com/index.p...st&p=129832

No polarization filters will be used during that observation. Usually they are used at much greater phase angles at Titan. In addition, we are not far enough north to catch specular reflection off Kraken Mare.

Ah right, thanks for that info. Great images to come I'm sure, even without polarisers.



Isn't that because they're usually being used to study layers within the atmosphere? For a lake shot presumably you'd want a lowish phase angle but with the lake suface viewed obliquely - preferably close to the Brewster angle.



I'm not sure I understand that point. I wasn't talking about specular reflection of the sun, just the sky. There should be sky reflected in the lake wherever you view it from.

Anyhow I look forward to an exciting flyby!

Sea on the horizon:

http://saturn.jpl.nasa.gov/photos/raw/rawi...?imageID=181367

T50 Mission description:
http://saturn.jpl.nasa.gov/files/20090207_...description.pdf

Some RAW images are up. Here is an image of Hotei Arcus at center (upside down):
http://saturn.jpl.nasa.gov/multimedia/images/raw/casJPGFullS47/N00130789.jpg ://http://saturn.jpl.nasa.gov/multimed...N00130789.jpg

Are there mountains southwest of Tsegihi???
VIMS and ISS are a bit at odds with each other!!!

Click to view attachment

We await the tie-breaker: SAR!

There might be, who knows. We've seen bland mountains. We've seen bright mountains. We've seen dark mountains.

Where be the dark mountains?

I know VIMS found some out in East Xanadu. I'll see if I can dig up an image.

Or you saw flat plains painted to look like mountains.... ;-)

Are you referring to the VIMS-water-icier tectonic ridges in N of Hotei Arcus?

By ISS, the tectonic ridges appear relatively darker compared to the really bright surrounding terrain.
By RADAR, the tectonic ridges appear much brighter than the surrounding terrain.
(Coordinated image here (Xanadu thread, post 24)

(The RADAR-dark/ISS-bright flow-like terrain is very interesting, it was seen in Xanadu, and also in Adiri near the Flower Petal Crater (Equatorial Sand Seas thread, post 375).

-Mike

I was referring to "Mabon" from Jason Barnes' 2007 paper.

An interesting SAR ride along swath to image bright streaks near the VIMS mountain ranges was to occur in T-50 (Feb 2009).
The CHARM presentation map of SARs for the Equinox misson from Dr. Spilker's presentation (see p.21 of her presentation at:
http://saturn.jpl.nasa.gov/files/20090728_...5yr_Spilker.pdf
The graphic below combines past ISS and VIMS images and the T-50 RA swath from that map. I've tried to have the starting, midpoint and endpoints of her map projected onto the same coordinates of the celestia grid. This shows the swath may miss the 'highest' VIMS mountain chain but may cover topography just to the east and south. One might expect radar bright terrain with drainage channels directed away from the VIMS ranges if indeed these are mountains.

Click to view attachment

Mountains within equatorial bright terrains look a bit darker (and icier) than their surroundings.

The original rationale for the "VIMS Mountains" that you point out was that they would be ridges if the lighting were due to the changing lighting angle. We've since seen this angle illuminated from the other direction (on T34), and it looks the same. So they might be mountains -- there are some darker blue patches within them that I would bet are mountains -- but they aren't the giant parallel mountains that we had initially thought.

- Jason

T50 was slightly to the north and west of the features noted in VIMS (which could be mountains, or could be
a nice painting of some mountains on a totally flat surface.. :-) ) There were a couple of chains of 'bright bits'
(totally unremarkable, see much of the same stuff in Shangri-La) in T50 but not particularly large or obviously elevated.

T60 (cross fingers) SAR should be right on top of the VIMS coverage, which is good for everyone, whatever the
features are.

Ralph, don't you think that you're being a bit, um, forward, by showing a giant picture of your penetrator as your icon? This is a family site! Your posts are NSFW!

- Jason

Is it a *giant* picture? I think not. Maybe you are easily impressed....

On a live TV interview on the night of the Huygens encounter, I was asked by
appealing scientist/broadcaster Lucie Green how deeply it penetrated.
Unfortunately I didnt have the presence of mind to remark that it isnt the
depth of penetration that matters, but the sensitivity of your instrumentation....

You my friend, made my day!

T50 Radar swath.
Click to view attachment

VERY belated for Ralph...

and T50 Targeted Distant Look
Click to view attachment

Thanks Peter. For those like me who have already forgotten where that was, a quote from the mission description:

•
RADAR: The instrument rides along with INMS at closest approach. During the flyby, the instrument will collect SAR of the mountain ranges southwest of Tsegihi that were suggested in VIMS data. Altimetry inbound and outbound completes the instrument’s plans.

EDIT: Scratch that - scroll back to post 16 for better info!

Interesting terrain. It looks like some lava flows at this resolution (first T50 image, upside).

Actually, they did cross two of the VIMS bright streaks... Hey, you know, I was wrong too, they also crossed my mid-latitude lake...

Right, so where are we? Can anybody post a map relating the SAR to the VIMS?

Click to view attachment

Here is an animated gif comparing ISS, VIMS, and RADAR views of this region.

That's very nice, thank you. That version of the ISS basemap looks like a great improvement over the version currently on Ciclops. The longitudinal streaks, though still present, are less prominent.

Yes, thanks VP for the correct orientation of the T50 RA and the nifty ISS basemap! I've incorporated those upgrades in the image below which includes the T23 swath and a background Celestia grid. The VIMS 'mountains' centered at 330W longitude and -30S latitude for the present remain as an interesting enigma, the loss of T60 SAR regretable!
Click to view attachment

My RADAR swath page is now updated to include the T50 swath:

http://pirlwww.lpl.arizona.edu/~perry/RADAR/

This includes the 256 pixels/deg. version of the swath as well as the ISS+RADAR basemap (RADAR through T50, ISS through T52)