[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]

The notion posted above, regarding Hyperion's deep craters acting as crude "mirrors" that could focus sunlight on the dark spots, is a very interesting one.

We need to keep in mind that the crater walls are not smooth surfaces and this will of course decrease any such effects. Also, Hyperion's craters seem to have cone-like shapes, which suggests to me that they might preferentially reflect sunlight straight back into space (much like the laser reflectors left behind by Apollo).

I haven't looked at any shots of Hyperion recently -- are there any for which the Sun was almost directly "behind" Cassini when the picture was taken? If so, it might be interesting to look at the apparent brightness of the craters, to see if they are reflecting an inordinate amount of light back towards the Sun. If they aren't, this notion of ray-focussing on the dark crater floors might really have something to it.

I know this is a bit off topic for the Iapetus thread -- however, it's perhaps arguable that _anything_ regarding dark material on Saturn's icy moons, is at least partially on topic where Iapetus is concerned.

[jmknapp]

The notion posted above, regarding Hyperion's deep craters acting as crude "mirrors" that could focus sunlight on the dark spots, is a very interesting one.

We need to keep in mind that the crater walls are not smooth surfaces and this will of course decrease any such effects.

Rather than reflection per se, maybe the idea is that the that the crater surfaces absorb sunlight and heat up, and then radiate infrared which is then focussed so to speak more in some places than others.