[X] My Assistant

[Exploitcorporati...]

With Cassini reentering the ring plane for the upcoming series of icy satellite encounters (crowned with the Iapetus flyby in September), it seems like a good time to open a few threads on the state of imaging coverage of these worlds and post on the new results as they come in. I'll start by picking on Tethys as we haven't seen anything new since December.

This is part of a poster project summarizing global and near-global views of the icy moons. All natural color images here are the work of ugordan with the exception of the first (Mattias Malmer) and the last (CICLOPS).
This will be replaced with an annotated and expanded version as time allows:

[Exploitcorporati...]

Much of my interest in Tethys stemmed from that teeny corner of the disc being revealed.The cause of the lost mosaic was well explained by edstrick somewhere a ways back...the images were taken but all but one were of black sky because Tethys wasn't where the scan platform was pointed at the time, much like the early Cassini nontargeted flybys of Dione and Enceladus where portions of the disc were missed due to position uncertainties. The albedo and cratering differences kinda make Tethys look "inorganic" to me...it reminds me of one of those digital image maps where the lighting and resolution changes from region to region.


I would really like anyone to explain how the viewing geometry in the pair of images below is possible. Both have north at the top, both are taken from below the ring plane, both show Tethys in the sky just beyond the eastern limb of Saturn. How is it you see Odysseus in the top frame and the Ithaca Chasma hemisphere in the bottom one? This has bugged me for ages. I'm sure it has to do with Cassini's position in it's orbit, but I can't visualize it.




EDIT: I just felt like slapping my forehead hard enough to knock my eyeballs out. It's because Tethys is on the other side of Saturn in the bottom one, huh?