[X] My Assistant

[ugordan]

Are there any plans for imaging Rhea on March 21? I noticed all other moons are on the wrong side of Saturn during periapsis passage except Rhea for which there's a pretty close pass, under 100 000 km, although closest approach happens at a very high phase angle.

Rhea approach geometry and closest approach from the Solar System Simulator.

[Guest_AlexBlackwell_*]

Are there any plans for imaging Rhea on March 21?

Yes, both ISS and CIRS have imaging sequences for rev 22 non-targeted encounters of Mimas and Rhea on March 21.

[Phil Stooke]

... and other moons! Here are Janus and Epimetheus passing each other. I used one frame as a base, enlarged 200%. Two other frames were then merged with each satellite image to reduce JPEG artifacts, plus a bit of other processing to improve feature visibility.

Phil

[ugordan]

Off-topic, but there are a bunch of images of a bright star taken during an occultation by Saturn. I looked at star charts a bit and it looks like it's Procyon.
Is this part of a UVIS stellar occultation with ISS riding along?
http://saturn.jpl.nasa.gov/multimedia/imag...eiImageID=68919

Check out this long exposure image of starlight being refracted by Saturn's atmosphere as the occultation proceeds, pretty cool!
I remember there was once a similar APOD showing the 3 stars in Orion's belt to be similarly smeared as the ISS (International Space Station, not Imaging Science Subsystem ) was moving and the stars were dipping lower into the Earth's atmosphere.

NAC RGB composite of the star:

[pat]

Off-topic, but there are a bunch of images of a bright star taken during an occultation by Saturn. I looked at star charts a bit and it looks like it's Procyon.
Is this part of a UVIS stellar occultation with ISS riding along?
http://saturn.jpl.nasa.gov/multimedia/imag...eiImageID=68919

Check out this long exposure image of starlight being refracted by Saturn's atmosphere as the occultation proceeds, pretty cool!
I remember there was once a similar APOD showing the 3 stars in Orion's belt to be similarly smeared as the ISS (International Space Station, not Imaging Science Subsystem ) was moving and the stars were dipping lower into the Earth's atmosphere.

NAC RGB composite of the star:

The name of the oibservation has "ALPCMIOCC" in it which I'd interpret to mean Alpha Canis Minor Occultation- so looks like Procyon it is then.

[ugordan]

Whoa! Titan, Janus and the rings: http://saturn.jpl.nasa.gov/multimedia/imag...eiImageID=69327

Many Rhea RAWs are also down, the crescent phase looks pretty similar to that enormous Dione crescent mosaic taken during its closest flyby.

Mimas in front of Saturn: http://saturn1.jpl.nasa.gov/multimedia/ima...eiImageID=69153

[alan]

Rhea images are up
http://saturn.jpl.nasa.gov/multimedia/imag...eiImageID=69227

[Bjorn Jonsson]

There are also some interesting images of a Mimas transit across Saturn from a distance of 190,000 km. This one is visually beautiful: http://saturn.jpl.nasa.gov/multimedia/imag...eiImageID=69153

[Phil Stooke]

Here are two of the Mimas images with a bit of a stretch to show near-terminator features better.

Phil

[ugordan]

There's a color, wide angle movie of Rhea transiting Saturn's disc. With plenty of patience and Photoshopping, that could be composed into a color movie.

A single frame, color is mainly guesswork based on previously released work:



Mimas in front of Saturn's disc . I used IR1/GRN/UV3, unfortunately the IR and green images were truncated so they didn't capture the whole disc of Mimas. I used synthetic color, using UV3 data to fill the missing portions.


Photoshop was used a good deal and this is more of an art image (especially the botom) than the real thing. Still, it turned out fairly nicely.

[TritonAntares]

There's a color, wide angle movie of Rhea transiting Saturn's disc.
With plenty of patience and Photoshopping, that could be composed into a color movie.

A single frame, color is mainly guesswork based on previously released work:

Fantastic view....

This image really shows the proportions between the tiny moons - here Rhea - and the giant Saturn with his rings.
Even the thinner part of Saturns' upper gasous surface is visible at his horizon:


Composing a color, wide angle movie of Rhea transiting Saturn's disc would be superb.
Can't wait enjoying it.

Bye.

[edstrick]

Stepping through the Rhea narrow-angle images, there's a surprising *LOT* of rotation visible betwen frames forming several frame mini-movies at each pointing.

[ugordan]

Stepping through the Rhea narrow-angle images, there's a surprising *LOT* of rotation visible betwen frames forming several frame mini-movies at each pointing.

That's actually a *BAD* thing from a color compositing point of view. I was expecting this to be a leisurely encounter, with very little perspective change in successive frames. Was I wrong...
Creating a color composite will require map projections and reprojections, the problem is probably even worse for different mosaic footprints.
Once again the ISS image acquiring speed underwhelms me

[edstrick]

AMEN. I don't understand why so much geometry change between frames.. this is not a super close encounter. (sigh)

[djellison]

Ciclops is quite old remember, it probably had to have its design frozen about 12 years ago.

Anyhoo - QT7 required :0
Doug

Attached File(s)

 janus_titan_rings.mov ( 276.84K ) Number of downloads: 494
 rhea_saturn_stack.mov ( 92.13K ) Number of downloads: 473

 

[ugordan]

AMEN. I don't understand why so much geometry change between frames.. this is not a super close encounter. (sigh)

When you have typically a minute between frames, even a slow encounter is bound to produce a difference. Take a multispectral observation of each footprint and the whole thing just falls apart.

Ciclops is quite old remember, it probably had to have its design frozen about 12 years ago.

I don't buy it. Galileo's SSI is basically early '80s or even late '70s technology and apparently it was much faster in terms of snapping images.
The problem might be due to the design of the SSR recorders on Cassini and their peak throughput, combined with other instruments' simultaneous demands. In light of that, the ISS team probably relaxed the speed in which the images could be taken.

[ugordan]

There's a high phase Enceladus sequence on the raw site now.
I stacked 6 frames and greatly enhanced the result to show the plumes emanating from the south pole:


The right image uses a color map to better show the extent of the plumes. The short sliver on the bottom left side of Enceladus' disk is the actual sunlit side, while the rest is saturnshine-lit region, severely saturated. The white region on the bottom are the rings, also heavily overexposed and motion-blurred.
JPEG artifacting is obvious even after stacking but the plumes are clearly still there.

[dvandorn]

Rhea images are up
http://saturn.jpl.nasa.gov/multimedia/imag...eiImageID=69227

I have often commented on how strongly I perceive the craters on Rhea to be arrayed in a variety of linear forms -- arcs and straight lines.

Look carefully at the plains between the larger craters in the image linked above. Near the terminator, they take on a positively furrowed or ridged appearance. Great expanses of the surface appear to be furrowed -- those in the right-center of the image (closest to the equator) all trend up-and-down in this image, while some furrowed terrain in the upper left portion of the crescent (a little farther from the terminator) appear to trend on a bottom-left-to-upper-right vector.

Rhea is displaying linear arrays of depressions at finer and finer levels. I insist that this must have some significance.

-the other Doug

[edstrick]

The Viking Orbiter cameras were designed with a fast readout cycle such that one camera was exposing and reading out while it's twin was erasing and resetting for the next exposure. I think the frame interval was 1.2 seconds between cameras so one camera cycled at 2.4 seconds total. This was necessary for strip-mosaicing of landing site candidates from a 1,500 km periapsis with a 50 meter/pixel resolution.

The drawback of the viking design was the data couldn't be recorded that fast in digital form on one tape track. The data was split into seven parallel data tracks, one pixel per track, then read out in track-sequential manner... which led to a lot of images missing one or many pixel-columns in a repetitive cycle. But they could take and record data in one hell of a hurry.

I don't know what led to the limitations in the Cassini camera frame rate, but it's almost apallingly slow.

[dilo]

High dinamic range image of Rhea+outer rings, color-coded combination of a long and a short esposure:

[dilo]

A beautiful true-color view of TETHYS at approximately 3,5 million kilometers away (taken on April 02), with night side of Saturn and partially shadowed rings...

Attached thumbnail(s)

 

[Bob Shaw]

Does anybody know what the strange 'glint' is in the rings above Tethys? A spoke? A reflection of off Tethys' illuminated half?

Bob Shaw

Attached thumbnail(s)

 

[dilo]

Does anybody know what the strange 'glint' is in the rings above Tethys? A spoke? A reflection of off Tethys' illuminated half?

Bob Shaw

I suspect is only the result of ring perspective + a cut from Saturn shadow...

[angel1801]

I was just wondering. When will we have furnished moasics of Rhea from the March 21, 2006 flyby?

[tasp]

Does anybody know what the strange 'glint' is in the rings above Tethys? A spoke? A reflection of off Tethys' illuminated half?

Bob Shaw

F ring braiding?


Weird perspective of it.

[Exploitcorporati...]

Rev 22 Saturnshine mosaics:

Rev 22 Sub-Saturn mosaics:

[Decepticon]

Oh Boy!


Gold as always!

[tedstryk]

Great work exploiting the data (sorry, I couldn't resist). Good to see you posting again!