Low inclination

[mmcirvin]

Two remarkable shots of Titan, Epimetheus, and the rings.

Peculiar conjunctions like these are a fairly common sight near the ring plane, where most of the major moons orbit. The recent shots in the raw archive are worth browsing at some length. Cassini will be at low inclination for the rest of this orbit, for the next couple of weeks (then there is an even closer flyby of Enceladus than last week's, and a flyby of Tethys). At some point, probably at the end of March when the next Titan flyby happens, I think it goes to a somewhat higher inclination for a while, moving to an orbit where it can study occultations of the Sun by the rings.

It will, however, be orbiting exactly in the ring plane from this fall through mid-2006, studying Saturn's magnetotail; during that time there will be no particularly pretty ring pictures, but probably lots of eerie-looking pictures of multi-crescent-moon conjunctions with the bright hairline of the ring system running through the middle. It will become graphically clear just how thin the rings are.

Comments

[mmcirvin.livejournal.com]

...Also, how inclined the various orbits are. Titan is, of course, further from Saturn than the perspective makes it look here; its orbit is only inclined about a third of a degree (all those paintings showing a spectacular Saturn seen from Titan with wide-open rings are bogus for more than one reason).

One thing that others of these pictures make clear, but that surprised me a little, is that Janus and Epimetheus's weird swapping co-orbits are actually slightly more inclined than those of the ring-shepherd moons Pandora, Prometheus, Pan and Atlas. It's only a small fraction of a degree, but they're close enough to the rings that it is noticeable and makes the perspective of some of these pictures hard to interpret. Mimas is at about a degree and a half; then of the other major moons within the orbit of Iapetus, only Tethys is as inclined as much as a degree.

[mmcirvin.livejournal.com]

Somebody put together an animated GIF of Dione occulting what I think is Tethys. (http://www.skytrip.de/temp/animation2.gif)

[mmcirvin.livejournal.com]

Also, that occultation sequence in the summer looks like it should produce some of the prettiest pictures of Saturn taken so far, something like the famous Voyager parting shot (http://solarsystem.nasa.gov/multimedia/display.cfm?IM_ID=2121) that you've seen a million times, only much higher-resolution, and with a thinner crescent Saturn and the rings backlit (the thick B ring looks dark from that angle, and thinner parts of the rings stand out as relatively bright). Classic science-fiction-cover-painting stuff, in other words. Though what I'm really looking forward to in that department are the super-high-inclination shots from the Titan 180 transfer in late '06, and the nearly polar orbit in '08.

(When I was a kid I liked drawing pictures of spaceships, and they got more and more detailed over time. I remember at one point in my adolescence imagining a massive manned expedition to Saturn on a ship that I named the Huygens—if the name of the proposed Titan lander had been chosen yet I didn't know it, though it's a pretty obvious name choice for anything going to Saturn—anyway, it went into a polar orbit so I could draw pictures of Saturn seen from above the poles.)