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Posted by: scalbers Jan 24 2006, 11:18 PM

As mentioned a couple of times in another thread I'm working on composing some stereo images of the "Snowman" craters that appear to reveal topographic details. Here is an initial fairly low resolution attempt so you can see what I'm up to. I've simply been blinking the images to see the stereo effect. Perhaps these images can be cropped and set up in such a way that they can be fused as well. One does have to use caution with interpreting terrain so near the limb of Iapetus. So without further ado, feel free to download the images at this URL:

http://laps.noaa.gov/albers/sos/saturn/iapetus/stereo

If this indexed link doesn't work for you please let me know and I can make explicit URLs for each image. Hope you don't have a fear of heights

Posted by: jmknapp Jan 30 2006, 02:52 AM

The links don't work for me, so I'd appreciate direct links to the images.

Thanks...

Posted by: Bob Shaw Jan 30 2006, 08:33 AM

I think the problem is with the file naming conventions, rather than the link. If you're using Windows, it'll pick up the last three characters after the final period and decide that it's found the file type. In this case, that leads to confusion.

If you're downloading, pop the files one at a time into a single-word named directory in the root of C: then run Command, and do a global copy and re-name on all files to 'tif' - eg copy c:\iapetus\*.* c:\iapetus\*.tif. Rename the .tif file that results as the *next* file you download will attempt to call itself the same name due to the extension issue discussed above.

Bob Shaw

Posted by: tasp Jan 30 2006, 03:00 PM

Or we can start a thread dissing Billy Gates and Microsoft . . . . .

Posted by: tasp Jan 30 2006, 03:01 PM

[duplicate post deleted, first time I have ever done that here, ]

Posted by: jmknapp Jan 30 2006, 03:59 PM

Thanks Bob... works now.

Posted by: scalbers Feb 2 2006, 07:57 PM

Hi all. I've gone ahead and set up an animated GIF that shows the stereo snowman effect I'm referring to at the URL shown below. This shows up best on the northern (upper) rims of the craters. Farther south, navigation and/or general bumpiness issues near the limb come further into play.

http://laps.noaa.gov/albers/sos/saturn/iapetus/stereo/animatesnowman.gif

Posted by: JRehling Feb 2 2006, 08:10 PM

Wow! Great work, which definitively shows that the dark edges of Snowman A and Snowman B are *inside* the craters, and, if deposited ballistically, arrived east to west. This definitively disproves two initially-plausible models:

1) That *all* of the dark stuff was collected from deep space onto Iapetus's leading hemisphere as Iapetus overran it.

2) That all of the dark stuff sprayed out from inside CR towards the edges.

A caveat would be that the Snowman craters landed on the boundary of CR and somehow exhumed dark material that ended up on the western sides of those craters. Obviously, that could only happen if the dark stuff was very substantial in depth.

Great clues!

Posted by: Michael Capobianco Feb 3 2006, 07:30 AM

Thanks much, Steve. I've taken your two images and made a red-cyan anaglyph composite. The result is spectacular. Several features do inded pop out, and it's easy to see the topography of the moat with its steep sides and uncentered central peak. Even with this additional informartion, it's still very difficult for me to understand the distribution of the dark stuff, especially if it's been flung into this region from somewhere else.

Here's the link to the image:

http://mysite.verizon.net/vzepeq2k/iapetus/id3.html

Michael

Posted by: Michael Capobianco Feb 3 2006, 05:47 PM

I guess I can put the image here: