Iapetus Far-Encounter between June 17 and 27 Options

[TritonAntares]

Hi,
as june begins, time to open this thread...

As said before there will be another Iapetus campaign in the second half of this month - from 17th until 27th.
Unfortunately the minimum distance will only be around 1,3 mio. km, resolution about 8,1 pxl/km.

Also the short Celestia-animation again:
 Iapetus_june_2006.avi.html ( 373K ) Number of downloads: 805

Just remove *.html and run the avi-file preferably on a DIVX-player.

Bye.

[jsheff]

Hi,
as june begins, time to open this thread...

As said before there will be another Iapetus campaign in the second half of this month - from 17th until 27th.
Unfortunately the minimum distance will only be around 1,3 mio. km, resolution about 8,1 pxl/km.

Also the short Celestia-animation again:
 Iapetus_june_2006.avi.html ( 373K ) Number of downloads: 805

Just remove *.html and run the avi-file preferably on a DIVX-player.

Bye.

That's very cool! Thank you. I've used Celestia before but not to the extent of simulating a flyby. Now that I know it can be done, I'm going to use it.

- John Sheff

[scalbers]

Greetings,

Thought I'd mention that I'm continuing to work on some map refinements, particularly to improve the consistency of features near the S/SE boundary of Cassini Regio. The lumpy shape of Iapetus, especially at high southern latitudes, makes it a bit challenging to reproject images onto consistent map locations given the assumption of a spherical (or even ellipsoidal) shape. I wonder if it's worth the exercise of improving my software to optionally include a shape model. Does anyone happen to have an extra shape model for Iapetus lying around? Perhaps I can learn to generate one myself using limb and/or feature fitting?

[TritonAntares]

Hi,
the first two june-shots of Iapetus are online.

Here an enlargement:

Date: 2006-06-05
Distance: 4.212.487 km (!)
Filters: CL1 and CL2

Remarkable the 2 giant impact bassins, one at the dark-bright border and the other one at the bottom - more difficult to see - in the dark area.

Bye.

[volcanopele]

Greetings,

Thought I'd mention that I'm continuing to work on some map refinements, particularly to improve the consistency of features near the S/SE boundary of Cassini Regio. The lumpy shape of Iapetus, especially at high southern latitudes, makes it a bit challenging to reproject images onto consistent map locations given the assumption of a spherical (or even ellipsoidal) shape. I wonder if it's worth the exercise of improving my software to optionally include a shape model. Does anyone happen to have an extra shape model for Iapetus lying around? Perhaps I can learn to generate one myself using limb and/or feature fitting?

What are you assuming for the ellisoidal shape? Are using a=747.1, b=749, c=712.6?

[scalbers]

VP,

It turns out I'm still using a spherical shape for Iapetus. I recently noted both a triaxial one (probably the one you mention) as well as an oblate spheroid one using a Google search of some literature. The two were so different I wasn't sure how much benefit using either would be. Perhaps the one you mention is more recent? The main point is that even a triaxial ellipsoid may be only a rough approximation in the vicinity of both the south polar region and the belly band. Perhaps its worth a try though.

I have so far used triaxial ellipsoids just in my Mimas and Enceladus map processing.

At any rate I've managed to get some improved consistency of the features in southern CR in my latest map update at http://laps.noaa.gov/albers/sos/sos.html#IAPETUS. This version includes PIA08164 from the April flyby.

[volcanopele]

The one I quoted is the most recent one from cassini observations and is in Thomas et al. 2006 (from LPSC, abtract 1639). See if that helps you any.

[TritonAntares]

Hello,
the next Iapetus-pic is online.

Here an ~4x enlargement:

Date: 2006-06-08
Distance: 3.822.476 km (!)
Filters: CL1 and CL2

No greater change...

Bye.

[TritonAntares]

Hi,
additional Iapetus-images are online.

Here a takeout , ~4x enlargement:

Date: 2006-06-14
Distance: 2.841.146 km
Filters: CL1 and GRN

To recognize the different bassins, a view through the Solar System Simulator:


Bye.

[TritonAntares]

Hi,
a full battery of 37 Iapetus pics has been released .

Here two takeouts , ~3x enlargement:

Date: 2006-06-17
Distance: 2.220.917 km
Filters: IR2 and CL2


Date: 2006-06-17
Distance: 2.219.152 km
Filters: P60 and MT2

An overview through the Solar System Simulator:


Bye.

[TritonAntares]

So,
another 51 Iapetus pics are online.

Here two takeouts , ~3x enlargement:


Date: 2006-06-20
Distance: 1.652.638 km
Filters: P0 and GRN


Date: 2006-06-20
Distance: 1.651.831 km
Filters: CL1 and CL2
Quite tall mountain visible on the right limb!

Overview through the Solar System Simulator:


Bye.

[TritonAntares]

Hi,
CASSINI transmitted further 31 Iapetus images.
Some widefield pics are also among them - maybe some positioning control or do they probably try to find some Iapetus coorbitals?
But these should be about 30° before or behind Iapetus...
This was taken:
June 21st - 11 tele/4 widefield pics
June 22nd - 14 tele/2 widefield pics

Here two takeouts , ~3x enlargement:

Date: 2006-06-22
Distance: 1.398.591 km
Filters: CL1 and CL2


Date: 2006-06-22
Distance: 1.398.128 km
Filters: P60 and MT2

And a widefield view:

Date: 2006-06-22
Distance: 1.396.785 km
Filters: CL1 and CL2

Overview through the Solar System Simulator:


Bye.

[Decepticon]

Looking good!

[ugordan]

Some widefield pics are also among them - maybe some positioning control or do they probably try to find some Iapetus coorbitals?
But these should be about 30° before or behind Iapetus...

Make that 60°... definitely much more than the wide angle field of view. This was a long exposure image, perhaps for optical navigation purposes.

[TritonAntares]

Make that 60°... definitely much more than the wide angle field of view. This was a long exposure image, perhaps for optical navigation purposes.

Yes, of course 60° - the Lagrangian points...