[X] My Assistant

[Rob Pinnegar]

According to the schedule on the main website, Cassini is gearing up for the "petal rotation" part of its tour. Consequently, it will be crossing the orbit of Iapetus several times between now and next spring.

Sadly, there are no close fly-bys (or should that be flys-by?) of Iapetus during this period, or in the subsequent parts of the tour between now and the close flyby scheduled for September 2007. However, just looking at some animations of the Cassini tour, it looks as if Cassini might get within a million kilometres of Iapetus once or twice during that period. Of course, Iapetus' orbital inclination to Saturn's equator complicates this, so it's hard to tell.

For those of you who have the software to do the calculations: What are the closest distant flybys of Iapetus between now and September 2007? Will any parts of Iapetus be seen at higher resolution than previously?

Also, what are the odds of a second Iapetus close flyby during the extended mission? I guess it's a bit problematical due to orbital-mechanical considerations and the fact that it would take up a lot of Cassini's time. However, I vaguely remember someone saying, a couple of months back, that it was under consideration.

[Decepticon]

As a comparison...

Note that these where taken over a Million KM out, and look what great detail we saw.

Theses images were taken with the narrow angle camera between October 15-20, 2004, from distances of 1.2, 1.1 and 1.3 million kilometers (746,000, 684,000 and 808,000 miles) from Iapetus, respectively. The Sun-Iapetus-spacecraft, or phase, angle changes from 88 to 144 degrees across the three images. The image scale is approximately 7 kilometers (4.5 miles) per pixel.

Source http://ciclops.org/view.php?id=624&flash=1

[tedstryk]

It will be interesting to see what we can do with the raws from those.

This image, which I posted before, was taken from 2.5 million km, produced using the raw data from July 13, 2004.

[Rob Pinnegar]

That's one of the images of the side of Iapetus that faces away from Saturn, right? Nice processing job.

Is this just an optical illusion, or does that large impact basin have a faint "phantom twin" just to its lower left? It could be that some craters are just lining up to look like an arc, I suppose.

It's too bad that Iapetus isn't more "full" in this image. From what I remember, there's a huge honkin' impact basin (in Roncevaux Terra) that would be around the upper left edge of Iapetus, as seen from the angle of this shot. It might be the biggest one on Iapetus, and there haven't been any good images of it yet, just fuzzy ones from a distance. We won't get a good look at it for two more years (but when we do it will be from really close).