Two big craters on Iapetus??

[Evil Dr Ganymede]

Take a look at this picture of Iapetus from the Cassini Raw Images and this new release from the Ciclops page.

One the first picture, there's a fairly large crater visible in the dark region near the terminator, with a diameter about half the height of the dark patch. On the second one, just above the centre of the satellite in the image within the dark patch, there appears to be another large crater that looks very similar. You can just see the eastern rim of the crater as a shadow that almost follows the edge of the dark region in the second image.

I'm pretty sure these aren't the same crater, since the first one doesn't appear to be near the edge of the dark terrain. I wonder if these have anything to do with the formation of the dark stuff though.

[lostfisherman]

That ciclops image is rather tantalizing, isn't it? You can just about make something out. It doesn't help that Iapatus' phase is almost full in that image.

Here is another picture showing another "circular region" in Iapatus' dark bit (called Cassini Regio if memory serves) as Iapatus revolves further on downward in the picture from the limb.

http://saturn.jpl.nasa.gov/multimedia/i ... 007059.jpg

Could it be the same feature? I find a bit tough to orientate myself compared with the image Evil Dr Ganymede posted.

http://ciclops.lpl.arizona.edu/media/ir ... _315_1.jpg

[Evil Dr Ganymede]

http://saturn.jpl.nasa.gov/multimedia/i ... 007059.jpg

Could it be the same feature? I find a bit tough to orientate myself compared with the image Evil Dr Ganymede posted.

That's definitely the same feature as in(the first Cassini image I linked to.

I'm not convinced that it's the same as the one in the Ciclops image.

Though now you mention it, the 10 degree phase angle makes it less likely that we're seeing a crater rim there... it could be a curved albedo feature in the dark terrain. Hrm.

[lostfisherman]

I guess I made myself lost somewhat, there are 2 distinct (to my mind) large crater like formations in the picture I linked to previously;

http://saturn.jpl.nasa.gov/multimedia/i ... 007059.jpg

They are almost touching each other, inside the dark region, they are similar in size. The one towards the top of the image does not have a central peak, and looks only tentatively like a crater, at least it looks to me a clear *circular formation* of some sort. There are clearer smaller craters towards its edge.

Hrm is a phrase that will be used a lot with this little world.

[Evil Dr Ganymede]

Oh yeah, now I see it...

I "Hrm" again!