Saturn moon Helene as never seen before.

[3488]

This is near enough a copy of the post I put on the Cassini thread in M&L, but this is just so awesome, so special & my jaw fell, when I saw these come in just now. Just had to bring them here on SS&A.

Helene images coming in. Helene is the leading trojan moon of the much larger Dione.

Helene is approx 36 KM across.

Helene in Saturnshine, an enlargement I have just done. The sunlit portion on the right is overexposed to bring out detail in the Saturnlit nightside of the leading Dione Trojan moon Helene.

Helene in front of Saturn's cloudtops enlarged crops I've just done.

Helene passing over Saturn's stormy cloudtops. A sharpened enlargement.

Andrew Brown. :shock: :shock:

 

[silylene]

Stunning! thank you for showing me this!

 

[3488]

Stunning! thank you for showing me this!

You are more than welcome silylene. I hope as many people have the chance to see these. :mrgreen:

NASA / JPL have released these soooooooo quickly too.

Three more.

All enlarged crops I have done.

Helene southern 'hemisphere'.

Whole detailed view of Helene in front of Saturn.

This one is a real sharp SKEET closeup. Cassini's cameras actually very nearly missed Helene altogether, but caught the dawn terminator. In just this tiny area just a KM long (resolution 11 metres, enlarged three times), much detail is visible, as is the lack of craters!!!

Andrew Brown.

 

[3488]

Last ones for tonight!!!! :lol:

Enlarged sharpened view of Saturnlit Helene, a different image to the earlier one.

Same view as above, but I have contrast enhanced it to bring out more detail. The dark circle just above the crater is due to a micrometeroid hit on the narrow angle camera lens. There are a few image artifacts, but the lack of small craters is apparent & some icy outcrops are also visible.

Andrew Brown.

 

[robnissen]

I love the Saturnshine pics, but they are all great. Thanks for posting.

 

[3488]

I love the Saturnshine pics, but they are all great. Thanks for posting.

You are so very welcome Rob. I just absolutely love this!!!! :mrgreen: :shock: :lol:

Right this IS the last one for tonight!!! Keep finding these. :shock:

Another frame that Cassini's cameras actually very nearly missed Helene altogether, but caught the dawn terminator. In just this tiny area, just over one square KM (I think) it is appararent how an icy layer is overlying another. It is possible to see ice boulders on the near rim of the crater & their shadows being cast on the opposing side!!!!!

Good Night everyone.

Andrew Brown.

 

[Gravity_Ray]

Is this just a big hunk of ice, or is there rock in there?

 

[CalliArcale]

*drools*

Y'know, it's jaw-droppingly gorgeous pictures like these that keep me coming to space sites. The deep space probes have seen such amazing things, and they share it all with us! It's . . . it's . . . well, humbling is one word that comes to mind, but it doesn't capture it all.

 

[3488]

Is this just a big hunk of ice, or is there rock in there?

Hi Gravity_Ray,

Hopefully very soon, we'll have a definite answer to that. Cassini passed close enough to Helene to have been perturbed slightly by the gravity & that perturbation would have been measured.

The short answer is I don't know.

The long answer is, given that Dione itself, is approx one third rock (with a small metallic core) & two thirds ice, may mean that Helene is similar in composition. However, it is more likely that Helene is a large hunk of ice, like a large icy comet nucleus in orbit around Saturn.

*drools*

Y'know, it's jaw-droppingly gorgeous pictures like these that keep me coming to space sites. The deep space probes have seen such amazing things, and they share it all with us! It's . . . it's . . . well, humbling is one word that comes to mind, but it doesn't capture it all.

It is amazing indeed. he only thing is due to a slight discrepancy in pointing i.e Helene was not where she was expected to be, meaning that many of the SKEET views were missed, we still got some great views, before Helene drifted out of frame due to the pointing error. Next year we get another close pass Helene & hopefully by then the orbit of Helene will be know accuratley enough to avoid this a second time.

At least Cassini did not impact Helene, which of course could have happened, if the error bar was much larger.

Andrew Brown.

 

[3488]

Three crops I have done. At least we got some decent imagery before Helene drifted out of view due to the pointing error.

A crater approx 5 KM wide on Helene. Strange 'flow' like patterns are seen in the icy surface.

An area approx 4 KM wide showing the southern part of the above crater & some ice hills / outcrops. A small ghost crater, probably ice filled can be seen.

A 4 KM wide area near the dawn terminator of Helene, more strange 'flow' like patterns are seen here along with a remarkably smooth area lacking any impact craters at all.

Andrew Brown.

 

[EarthlingX]

*drools*

Y'know, it's jaw-droppingly gorgeous pictures like these that keep me coming to space sites. The deep space probes have seen such amazing things, and they share it all with us! It's . . . it's . . . well, humbling is one word that comes to mind, but it doesn't capture it all.

*nods vigorously*

 

[3488]

Emily Lakdawalla compiled the first ever mini atlas of Helene. Fascinating.

The Saturn facing side is more heavily cratered then the 'far side'. Helene is Kronosynchronous, i.e keeps the same face turned towards Saturn.

Helene mini atlas

Another: Wednesday 3rd March 2010 image I have worked on.

Eerie Wednesday 16th August 2006 view.

Andrew Brown.

 

[EarthlingX]

Emily Lakdawalla compiled the first ever mini atlas of Helene. Fascinating.

The Saturn facing side is more heavily cratered then the 'far side'. Helene is Kronosynchronous, i.e keeps the same face turned towards Saturn.

Helene mini atlas

Another: Wednesday 3rd March 2010 image I have worked on.
http://i233.photobucket.com/albums/ee18 ... assini.jpg

Eerie Wednesday 16th August 2006 view.
http://i233.photobucket.com/albums/ee18 ... assini.jpg

Andrew Brown.

That atlas is 'wow' ( and on my disk ) .. I have to emphasize this :


Man, i'm glad you're back, you made me a Lunaris Kronos addict ( my Latin sux )

 

[3488]

Yes I under Lunaris Kronos & am also a Lunaris Jove addict. :mrgreen:

Two sharpened enlargements from the Helene mini atlas of the more cratered Saturn facing side.

Saturn facing side, this centre of this view is sub Saturn.

Trailing side of Saturn facing side. The far side is just visible on left.

Andrew Brown.

 

[ZenGalacticore]

Awesome pics, great detail! Thanks.

(Looks mighty cold and lonely out there though!)

You are very welcome indeed. :mrgreen:

I absolutley love this. It is very cold & lonely out there. Helene being quite reflective, will be cold, even for the Saturn system, surface temperature approx minus 200 Celsius.

It's great to see that a few of the minor memebers are getting some proper attention. Helene will be approached again next June, Calypso recently had a good mid distance pass as has Telesto & Telesto will be approached again in 2014 I think.

Andrew Brown.

 

[EarthlingX]

Yes I under Lunaris Kronos & am also a Lunaris Jove addict. :mrgreen:

Horrible :shock: So many addictions ! I have similar problems, maybe it's time to find some counselling ? Hmm .. Not :twisted:

Two sharpened enlargements from the Helene mini atlas of the more cratered Saturn facing side.

Saturn facing side, this centre of this view is sub Saturn.
http://i233.photobucket.com/albums/ee18 ... assini.jpg

Trailing side of Saturn facing side. The far side is just visible on left.
http://i233.photobucket.com/albums/ee18 ... assini.jpg

Andrew Brown.

I was digesting those images with 'layers', and i wonder, wouldn't Helene's orbit cause tidal effects ? Could those effects, if existing, cause those parallel lines ?

Having these images neatly zoomed, accompanied with your comments, really helps

 

[3488]

Hi EathlingX, another sharpened enlarged crop from the Helene mini atlas. The Farside of Helene on left, sunlit, the nearside Saturnlit. This is a composite of two images, put together. I have taken some of the 'noise' away.

Andrew Brown.

 

[EarthlingX]

Wow Impressive work :shock:

I made animation from the same atlas, just not sure if it helps ? ( image change every should be every 10 sec )

 

[3488]

Just been looking at Helene images again.

This one is quite strange. A 3 KM wide ghost crater with the curious flow like wrinkling within it.

Also this 9 KM wide crater. Can see striation within the bowl shaped interior & what appears to be a crustal layer around the rim.

10 KM wide section of surface on Helene that was difficult to see as the Sun was more or less overhead. I have cropped out, sharpened enlarged & contrast enhanced this area. There are imaging artifacts, but I have bought out more clearly a 2 KM wide shallow flat floored crater on the left & some hummocky ice hills.

Andrew Brown.