Cassini Equinox & Solstice Mission, (nine year extension)!!.

[3488]

Re: Cassini Equinox Mission (Cassini's two year extension).

Another image of the Saturn moon Prometheus that I have just worked on, from a slightly different angle. I have enlarged it, sharpened it & removed most of the instrument noise.

Andrew Brown.

 

[EarthlingX]

Re: Cassini Equinox Mission (Cassini's two year extension).

:shock: wha. .what did you do to this images :shock: :mrgreen:

Wonderful detail under zoom, lovely areas in the shade, very, very zoomable.

I think, i'm beginning to see rock halving layers everywhere. I hope, it's curable. There are parallel lines, could be indicative of layers, on the upper right in the above image.

 

[3488]

Re: Cassini Equinox Mission (Cassini's two year extension).

Hi EarthlingX, I use Ability Photopaint Studio.

Another enlarged crop I've done of the 145 KM x 85 KM x 62 KM Saturn moon Prometheus.
A 'crescent' Prometheus, enlarged & sharpened.

The Saturnshine nightside, enlarged, sharpened & contrast enhanced.

Andrew Brown.

 

[EarthlingX]

Re: Cassini Equinox Mission (Cassini's two year extension).

Hi EarthlingX, I use Ability Photopaint Studio.

Thank you, will look into it.

Another enlarged crop I've done of the 145 KM x 85 KM x 62 KM Saturn moon Prometheus.
A 'crescent' Prometheus, enlarged & sharpened.

Is there a word for being obsessed by layers ?

The Saturnshine nightside, enlarged, sharpened & contrast enhanced.

Andrew Brown.

Thank you, very nice and, oh, yea new avatar i know that place :mrgreen:

 

[3488]

Re: Cassini Equinox Mission (Cassini's two year extension).

On Wednesday 24th March 2010, the Cassini Spacecraft observed the irregularly asteroid shaped, 138 x 110 x 110 km sized ice moon Epimetheus pass just to the south of the second largest of Saturn's attendants, the large 1,528 KM wide undifferentiated rock ice ball moon Rhea.

Epimetheus was 1.62 million KM from Cassini, Rhea was 1.24 million KM away.

In the background are Saturn's storm tossed cloudtops & the rings highly foreshortened.

Epimetheus appears to the lower left of this enlarged sharpened crop.

Epimetheus passes below Rhea's south pole.

Epimetheus drifts off towards the lower right.

Andrew Brown.

 

[EarthlingX]

Re: Cassini Equinox Mission (Cassini's two year extension).

A cut from Calypso Close Up :

The Cassini spacecraft's February 2010 encounter with Calypso yielded this incredibly detailed view of this Trojan moon.
Irregularly shaped Calypso is one of two Trojan moons of the larger moon Tethys; Calypso trails Tethys in its orbit by 60 degrees.

Streaks, looking like a flow. How much can this moon get gravitationally pulled around, and still keep it's orbit ?
If it would be made from a couple of parts, which would oscillate, would that not cause something similar to what we see ?

 

[3488]

Re: Cassini Equinox Mission (Cassini's two year extension).

Thanks EarthlingX,

I see that the earlier images were upside down!!!!

Below is a an enlarged sharpened crop of the western side & terminator of Calypso. What is immediately obvious with this vastly improved image from NASA that EarthlingX posted & my crop below is that like the Dione leading Trojan Moon Helene, is that there appears to be 'glacial like flows' & lack of small impact craters.

An enlarged crop of the eastern end of Calypso. Icy outcrop of ghost crater??

Andrew Brown.

 

[EarthlingX]

Re: Cassini Equinox Mission (Cassini's two year extension).

Could it be tracks ? Something dragging over the surface ? This tracks have rather well expressed 'walls' .. How could something be dragged over the surface, and again - gravitational tugging ?
They remind me of Phobos tracks/striations, btw.

 

[Fomalhautian]

Re: Cassini Equinox Mission (Cassini's two year extension).

Do you think the glacial-like flows and lack of small craters is a result of loose ice particles being pulled around by gravity, or something like sandblasting from Saturns e-ring? I can't imagine anything ever actually flowed there.

BTW, great work as usual Andrew. Thanks.

 

[3488]

Re: Cassini Equinox Mission (Cassini's two year extension).

It's wonderful to have you back Fomalhautian. :mrgreen:

Far too long no see.

I suspect it's a bit of both. Calypso, like all irregular bodies have varying surface gravities across their surfaces & that gravity may not go straight down into the surface, it could pull several degrees to one side, if the body is really potato shaped like Calypso, Telesto, Helene, Prometheus, Pandora, Mars moons Phobos & Deimos, Jupiter moons Amalthea, Thebe & Metis, asteroids 243 Ida, 433 Eros, 951 Gaspra, 25143 Itokawa, etc, due to one part of the body being 'larger' than another (a bit difficult to explain really).

In short an irregularly shaped body will have varying strengths & directions of surface gravity dependent on where on the body it is.

Perhaps these 'ice flows' seen on Calypso (Tethys trailling trojan moon) & more recently on Helene (Dione leading trojan moon), are symptomatic of that.

The source of the icy debris could be the rings of Saturn & / or the geysers of Enceladus.

Interesting point. The images of both Calypso & Helene are sharp enough to investigate this properly. Telesto, also appears smoothed off, but lacks flow like features, strange. It does not seem as if we will get a close look at Polydeuces (the tiny Dione trailling trojan moon, approx 10% the size of Helene or approx 4 KM wide)

Andrew Brown.

 

[EarthlingX]

Re: Cassini Equinox Mission (Cassini's two year extension).

Can anyone explain what is going on here ?

Ciclops : Pan's Effects

I rotated and resized this image, and did some zooming, to show what is puzzling me :

Resized and 90 deg CC rotated image :

Pan and the puzzle :

Waves, centred on the dot :

Cut with the lower part of ring visible :

New moon forming ? All of this from the tiny Pan ?

 

[nimbus]

Re: Cassini Equinox Mission (Cassini's two year extension).

I doubt they'd have missed it all this time. If you look at a complete list of moons of Saturn and search the NASA material for the nearest ones inside of Pan, it ought to show up. Simplest explanation then is that that little moon was ignored in the Pan picture press release.

..
Pan orbits in the Encke gap, A ring.

Wiki says A ring has moonlets, and also says " It is estimated that the A Ring contains thousands of such objects", where "objects" means moonlets "too small to image". So the one visible in the above pic is probably already known.

 

[EarthlingX]

Re: Cassini Equinox Mission (Cassini's two year extension).

I doubt they'd have missed it all this time. If you look at a complete list of moons of Saturn and search the NASA material for the nearest ones inside of Pan, it ought to show up. Simplest explanation then is that that little moon was ignored in the Pan picture press release.

..
Pan orbits in the Encke gap, A ring.

Wiki says A ring has moonlets, and also says " It is estimated that the A Ring contains thousands of such objects", where "objects" means moonlets "too small to image". So the one visible in the above pic is probably already known.

Yea, you're most probably right. I kinda just dropped it in, it was a boring day in the Saturn orbit .. :roll:

I go check Wiki now, should've done that before .. .. And yea, see that bulge behind it ? It somehow draws images of trojan moons into my mind, and after watching this images for a while (posting them here was a cheat), i noticed, they might be actually caused by the bulge.. I did read the Ciclops page, though .. :arrow:

Looks like that 'bulge' is called a ringlet :
Wiki : Pan Ringlet

And Encke gap explains the rest, i think :
Wiki : Rings of Saturn - Encke gap
Spiral density waves visible on both sides of it are induced by resonances with nearby moons exterior to the rings, while Pan induces an additional set of spiraling wakes (see image in gallery).[26]

 

[nimbus]

Re: Cassini Equinox Mission (Cassini's two year extension).

So that bright spot in the image is just a bright shining ring bulge? Or do you mean that the wake behind it in the rings is indicative of (or at least consistent with) an actual object?

it was a boring day in the Saturn orbit ..

There's such a thing??

 

[EarthlingX]

Re: Cassini Equinox Mission (Cassini's two year extension).

So that bright spot in the image is just a bright shining ring bulge? Or do you mean that the wake behind it in the rings is indicative of (or at least consistent with) an actual object?

That bright spot is nothing special, i think, some surface turned to reflect light, accident, so to speak. But it caught my attention, and maybe i will learn something.

Yes, i thought it is about some other object, like that ringlet, but now i have to read some more, before writing more silly opinions

it was a boring day in the Saturn orbit ..

There's such a thing??

of course not

edit:

a couple of related papers from the Cassini team, i guess :

• - Hahn, J.M., Spitale, J.N., Porco, C.C. (2009). "Dynamics of the Sharp Edges of Broad Planetary Rings" Astrophysical Journal 699, 686-710.
  - Weiss, J.W., Porco, C.C., Tiscareno, M.S. (2009). "Ring Edge Waves and the Masses of Nearby Satellites" Astronomical Journal 138, 272-286.
  - Hedman, M.M, Burns, J.A., Tiscareno, M.S., Porco, C.C. (2009). "Organizing some very tenuous things: Resonant structures in Saturn's faint rings" Icarus 202, 260-279.

 

[EarthlingX]

Re: Cassini Equinox Mission (Cassini's two year extension).

Two events around the corner :
Cassini Doubleheader: Flying By Titan and Dione

Apr. 02, 2010

In a special double flyby early next week, NASA's Cassini spacecraft will visit Saturn's moons Titan and Dione within a period of about a day and a half, with no maneuvers in between. A fortuitous cosmic alignment allows Cassini to attempt this doubleheader, and the interest in swinging by Dione influenced the design of its extended mission.

Titan Flyby (T-67) - April 5, 2010

This is one of the two most important Titan encounters for the Imaging Science Subsystem (ISS) in the extended mission. These high (about 7,000 kilometer) flybys were designed to provide very long, low phase, high-resolution views of Titan's surface.

Dione Flyby (D-2) - April 7, 2010

Cassini swoops down to within about 500 kilometers (311 miles) of Dione to “sniff” the moon. Particle and fields instruments will try to determine if Dione is actively spewing particles.

 

[EarthlingX]

Re: Cassini Equinox Mission (Cassini's two year extension).

A bit more about Pan and Encke gap from a Science article, published in 2005 :
Cassini Imaging Science: Initial Results on Saturn’s Rings and Small Satellites (pdf)

Edge waves are seen in the outer Encke gap edge, in which the particles are trailing Pan by 348º or ~457 wavelengths: Their dominant wavelength is 0.81º and their amplitude ae = 0.4 km. The distance of Pan from the outer edge is ~161 km, a value that is not consistent with such a wavelength (which yields x ~ 201 km). Either Pan is not responsible for the waves seen in the outer edge (Fig. 9B) and they indicate the presence of another moonlet in the gap ~40 km interior to Pan, or the simple kinematical model for edge wave development by Pan does not apply to this edge. The second putative moonlet would have to be ~25% of Pan's mass, and for the same density, ~60% of Pan's size. Such a moon would have been easily detected in Cassini movie sequences of the Encke gap. On the other hand, it is hard to imagine a process that would alter the wavelength/distance relation on the outer edge and not on the inner edge, because the ring material interior and exterior to Pan has comparable optical depths and therefore surface mass densities. Cassini images of the Encke gap, and the large number of wakes due to Pan and second- and third-order waves, suggest that there is far less damping than the simplest, streamline intersection treatment of this dynamical system would predict (52, 68, 69).

 

[EarthlingX]

Re: Cassini Equinox Mission (Cassini's two year extension).

SDC : Mystery of Saturn's Rings May Finally Get Answer From Cassini Probe

By Andrea Thompson

posted: 06 April 2010
07:51 am ET

The rings of Saturn have been known of since telescopes began peering at the heavens. Galileo first spotted them in 1610. Since that time, astronomers have learned more and more about Saturn's most striking feature, from the material that makes up the rings to the forces that jostle that material around.

But two of the most basic-sounding pieces of information about Saturn's rings — their mass and age — remain something of a mystery.

These questions are "the big elephant in the room," said Jeff Cuzzi, interdisciplinary scientist for rings and dust for NASA's Cassini spacecraft. Cuzzi is based at NASA Ames Research Center in Moffett Field, Calif.

This mosaic of the Saturn system, taken by Cassini, glows with scattered light from tiny dust grains. The sun is obscured by the planet in this unusual geometry. Credit: NASA/JPL/CICLOPS

 

[3488]

Re: Cassini Equinox Mission (Cassini's two year extension).

On Wednesday 7th April 2010, Cassini imaged the 193 KM by 173 KM by 137 KM Janus.

Also on the same day the 135 KM by 108 KM by105 KM Epimetheus.

The main event on the same day by far was the close pass of Dione.

Remus Crater approx 70 KM wide (I think) with thrust faults running through.

15 KM wide area, I think in the Eurotas Chasmata area on Dione

Enlarged crops from above. Massive thust faulting.

Interesting crater in icy surface with striations on the walls as material has slid inside.

I am feeling a little unwell right now so this is a quick chime in.

Andrew Brown.

 

[3488]

Re: Cassini Equinox Mission (Cassini's two year extension).

Dione backlit in front of Saturn's rings. The star to the lower left I think is Ancha / Theta Aquarii .

Enlarged, sharpened crop of above.

Enceladus as seen from Cassini. Wednesday 7th April 2010.

Another here of the 135 KM by 108 KM by 105 KM Epimetheus.

Andrew Brown.

 

[EarthlingX]

Re: Cassini Equinox Mission (Cassini's two year extension).

:mrgreen: :arrow:

 

[3488]

Re: Cassini Equinox Mission (Cassini's two year extension).

Quick chime in. Been out all day & only just got back.

Below I thought was very interesting.

Prometheus passing north of Rhea which in turn was partially obscured in the northern hemisphere by Saturn's rings. Thursday 8th April 2010.

Reduced full frame to 755 pixels, so could fit on here.

Enlarged, sharpened, crop.

Link to a 2,048 pixel wide sharpened, enlargement.

Tomorrow evening, I should be back properly.

Andrew Brown.

 

[3488]

Re: Cassini Equinox Mission (Cassini's two year extension).

On Saturday 10th April 2010, Cassini observed Dione pass directly in front of Titan.

Dione's varied geologically enriched surface crosses Titan's chemically enriched atmospheric face.

I think Dione is moving from right to left.

Contrast enhanced actual size crops.

Enlarged, contrast enhanced sharpened crops.

Andrew Brown.

 

[MeteorWayne]

Re: Cassini Equinox Mission (Cassini's two year extension).

Somehow Wow!!!!!!!!!!!! doesn't seem like enough.

Thanx, Andrew!

 

[3488]

Re: Cassini Equinox Mission (Cassini's two year extension).

I absolutely love this Wayne. :mrgreen:

I worked on an earlier one in the sequence below. :shock:

Actual size enhanced crop.

Enlarged sharpened crop.

Andrew Brown.