[X] My Assistant

[Decepticon]

Here's what extrapolating the current SPICE kernels yields:

IAPETUS 2005 NOV 12 14:34:49 185078153 415,451 km arcmin=12.1
IAPETUS 2006 JAN 25 21:13:08 191495653 873,345 km arcmin=5.7

IAPETUS 2006 APR 11 17:16:28 198047853 602,419 km arcmin=8.3
IAPETUS 2007 SEP 10 12:31:28 242699553 1,259 km arcmin=2186.8

Posted by jmknapp

This time a little further out.

Jan. 2006 - 879,000 km - 5.3 km/pixel - eastern Cassini Region and transition zone, part ofthe "moat" posted by VP


If anyone has made a animation of the encounter please post it!

[Rob Pinnegar]

One more thing...

Take a look at the image of Iapetus at:

www.nineplanets.org/iapetus.html

and compare it with the map shown earlier in this thread.

The Nine Planets Cassini image shows a big impact structure near the south pole (on the terminator at the extreme right side of the image) whose location can be referenced to the even larger Roncevaux Terra basin, here located on the terminator to the right of centre.

Looking at the "red circle" map: The Roncevaux Terra impact basin can also be seen here, and when the two images are compared, it looks very much as if that south-pole impact structure should be located quite close to the red circle.

Thus the irregularity in the "white mountain" region of the south pole could be due to the topography of this impact structure. Perhaps its outline is not as easy to discern when seen from the Saturn-facing side of Iapetus, as compared with the Saturn-backing hemisphere (as in the Nine Planets image).

[TritonAntares]

The Nine Planets Cassini image shows a big impact structure near the south pole (on the terminator at the extreme right side of the image) whose location can be referenced to the even larger Roncevaux Terra basin, here located on the terminator to the right of centre.

Looking at the "red circle" map: The Roncevaux Terra impact basin can also be seen here, and when the two images are compared, it looks very much as if that south-pole impact structure should be located quite close to the red circle.

Thus the irregularity in the "white mountain" region of the south pole could be due to the topography of this impact structure. Perhaps its outline is not as easy to discern when seen from the Saturn-facing side of Iapetus, as compared with the Saturn-backing hemisphere (as in the Nine Planets image).

I guess you mean this encircled south-pole impact structure:

This crater alone should be to small to cause such a great irregularity.
The large Roncevaux Terra bassin seems more likely to have disturbed the whole region,
or there probably exists another hidden bassin.
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Concerning the upcoming April far-encounter, I do not believe an opportunity to observe
the south-polar hemisphere under optimal contrast conditions as cresent will be thrown away.