Dione Options

[remcook]

you know....it's great to be here! some amazing work!

[mike]

Wow. That's an amazing photograph.

[CosmicRocker]

Would anyone be willing to provide a link to a description of the different filters used by Cassini, and perhaps another with an explanation of the file naming conventions used for the raw images?

This feiImageID=xxxxx stuff looks pretty cryptic to me. Am I missing something?

This same information from the MER mission was relatively easy to obtain.

[djellison]

Would anyone be willing to provide a link to a description of the different filters used by Cassini, and perhaps another with an explanation of the file naming conventions used for the raw images?

This feiImageID=xxxxx stuff looks pretty cryptic to me. Am I missing something?

This same information from the MER mission was relatively easy to obtain.

Unfortunately - there isnt the same MER convention. They're just sequential numbers

However - on the page describing each frame is a descriptor

i.e.

http://saturn.jpl.nasa.gov/multimedia/imag...&storedQ=762004

Lots of piccies -all of the same thing - so you can guess, lots of different filters

What you WANT - is the ones with CL1 and RED, GRN and BL1

On that page - they start with the last one - and the first two of the following page...thus

http://saturn.jpl.nasa.gov/multimedia/imag...eiImageID=29068

http://saturn.jpl.nasa.gov/multimedia/imag...eiImageID=29067

http://saturn.jpl.nasa.gov/multimedia/imag...eiImageID=29066

You often find that if there are a LOT of images of the same thing ( i.e. it's been taken thru lots of filters ) - if there ARE Red,Green and blue then they are often the 5th, 4th and 3rd from last of the sequence - or there abouts!

Doug

[Stu]

Doug,

Hope you don't mind, but I just wanted to say a big, and overdue, thank you for sharing all the amazing pics - first of Mars, and now Saturn, etc - you take so long producing. I'm sure that I speak for many people who visit this Forum when I say that your site is as much a part of our browsing routine now as the official NASA MER and CASSINI websites, and you constantly amaze us with the quality of your work here. Each time I go online and visit the site I feel spoiled by the latest wonders from you, and very grateful to you for sharing them with us.

Wider - and official - recognition of your imaging work is long overdue.

[volcanopele]

Are these fractures from tidal forces?

Dinoquakes

If they were, I'd expect them to be centered on the anti- or sub-Saturnian hemispheres but instead they are roughly centered in the trailing hemisphere. My thinking is that early in Dione's history (given that there are a few large craters post-dating the fracturing) a diapir of warm ice inpinged on the brittle icy crust from below. The extent of the volcanism was just a round of outgassing that produced the dark diffuse material (dark in UV). Then as the stresses increased, the crust fractured as you see it today. This must have been early, maybe ~4 Ga, or there abouts. that's just MY idea, I still haven't vetted that through the team and I am certainly no expert on the history and physics of mid-sized icy satellites. I am just trying to come up with a way to causing such extensive fractuing focused on one area (and dark material in one area) yet have much of the rest of the satellite look as dead as a doornail.

[volcanopele]

Oh YES! Fantastic:

That's part of a huge sequence of images in MANY filters. I am actually surprised to see that Doug hasn't tried to play around with that.

If you are Doug, and just not done yet, use the two UV filters (UV3 and UV1) as two of your filters then select what ever you want as red and be ready for a great view

[Bjorn Jonsson]

I can't wait to see global maps of dione. Is anyone working on a Updated Voyager/Cassini Global map?

I plan to do a quick and dirty (similar to the Tethys map I posted a few weeks ago in a different thread) cylindrical map of Dione as soon as I can but unfortunately I probably do not have time to do so until next week at earliest.

[tedstryk]

Check out
http://photojournal.jpl.nasa.gov/catalog/PIA06162

I knew it!!! I knew they had to take a global mosaic. Wonder why all the raw data wasn't released. There are a whole lot of Titan and Doine images on the photojournal now.

[alan]

Lots of new images at cassini site check out the haze layers
http://photojournal.jpl.nasa.gov/jpeg/PIA06160.jpg

[alan]

From cassini home

http://photojournal.jpl.nasa.gov/jpegMod/PIA06162_modest.jpg

"Five narrow angle frames comprise this view of the `wispy terrain' on the anti-Saturn side of Dione. To the surprise of Cassini imaging scientists, the wispy terrain does not consist of thick ice deposits, but rather the bright ice cliffs created by tectonic fractures. The surface is also clearly very heavily cratered. The image scale is 0.9 kilometers (0.6 miles) per pixel; the phase angle is 34 degrees."

I was expecting the same thing, large deposits of ice, I thought the dark areas around the bright wisps were deposits that had darkened with age, was expecting to see the same thing on Iapetus. Well, there goes that theory.

[CosmicRocker]

Unfortunately - there isnt the same MER convention.  They're just sequential numbers

Thanks, Doug. That really explains a lot. It's unfortunate one has to dig for such basic info. I wonder why the Cassini team didn't use a more efficient naming convention, like the one used by MER.

Now, the only thing I'd like to find is a listing of the filters with the wavelengths and bandpasses of each.

[CosmicRocker]

Are these fractures from tidal forces?

I don't know what caused those fractures, either. But their Horst and Graben geometry indicates they were caused by tensional forces, rather than compressional ones. Something stretched the crust apart to form them.

A simple increase in the internal temperature of Dione could cause them. So could some kind of convection mechanism.

[djellison]

Check out
http://photojournal.jpl.nasa.gov/catalog/PIA06162

I knew it!!! I knew they had to take a global mosaic. Wonder why all the raw data wasn't released. There are a whole lot of Titan and Doine images on the photojournal now.

That's just a single frame taken from further out

Doug

[remcook]

http://www.spaceflightnow.com/cassini/041216science.html

Cassini imaging scientists are intrigued by the complex braided structure of surface fractures on Dione. To the surprise of scientists, the wispy terrain features do not consist of thick ice deposits, but bright ice cliffs created by tectonic features. "This is one of the most surprising results so far. It just wasn't what we expected," said Dr. Carolyn Porco, Cassini imaging team leader, Space Science Institute, Boulder, Colo.