Saturnian Moon Identification - Unmanned Spaceflight.com

Saturnian Moon Identification, How to tell one moon from another?

David View Member Profile	Oct 6 2005, 02:57 PM Post #1
Member Group: Members Posts: 809 Joined: 11-March 04 Member No.: 56	Most of Saturn's nine largest moons have some characteristic that distinguishes them from the others, by which I can more or less instantly recognize them when I see their images: Titan is big, orange, and smoggy Iapetus is pied black and white, with an immense crater, irregular shape, and that wacky equatorial ridge (almost too many weirdnesses for one moon!) Enceladus is small, icy, and smooth like a spherical hockey rink, with those warm antarctic catscratches Mimas is small, bumpy, egg-round, with a really big crater Hyperion is irregular and pocked full of medium-sized black-bottomed holes Phoebe is potato-shaped with a less dense pocking of conical craters, plus a few larger ones But the three I still have a lot of trouble distinguishing are Rhea, Dione, and Tethys. I know Rhea is considerably larger, but the scale difference isn't enough to make it a lot less lumpy than the other two, so that doesn't help much. What distinguishing marks should I look for to be able to easily differentiate these three moons?

Replies

volcanopele View Member Profile	Oct 6 2005, 05:32 PM Post #2
Senior Member Group: Moderator Posts: 3242 Joined: 11-February 04 From: Tucson, AZ Member No.: 23	Tethys: smaller than Rhea, rugged terrain, Odysseus and Ithaca Chasma prominent, look for Penelope-Phemius-Polyphemus-Ajax grouping of craters Dione: Prominent wispy terrain on dark background, smoother topography than Tethys elsewhere, south polar impact basin Rhea: Two large impact basins in anti-Saturnian hemisphere (Tirawa and ... S. Tirawa), ray crater, rugged like Tethys but bigger, wispy terrain with lighter background than Dione's and with fewer "branching arms", Two impact basin south and east of wispy terrain (Izanagi) -------------------- &@^^!% Jim! I'm a geologist, not a physicist! The Gish Bar Times - A Blog all about Jupiter's Moon Io

ljk4-1 View Member Profile	Nov 11 2005, 02:55 PM Post #3
Senior Member Group: Members Posts: 2454 Joined: 8-July 05 From: NGC 5907 Member No.: 430	That Cassini probe sure knows a photo op when it sees one: http://www.universetoday.com/am/uploads/20...emoons-full.jpg As wonderful as the Voyagers were, Cassini is proof positive that a couple of flybys just are not enough. -------------------- "After having some business dealings with men, I am occasionally chagrined, and feel as if I had done some wrong, and it is hard to forget the ugly circumstance. I see that such intercourse long continued would make one thoroughly prosaic, hard, and coarse. But the longest intercourse with Nature, though in her rudest moods, does not thus harden and make coarse. A hard, sensible man whom we liken to a rock is indeed much harder than a rock. From hard, coarse, insensible men with whom I have no sympathy, I go to commune with the rocks, whose hearts are comparatively soft." - Henry David Thoreau, November 15, 1853

ljk4-1 View Member Profile	Jan 25 2006, 05:22 PM Post #4
Senior Member Group: Members Posts: 2454 Joined: 8-July 05 From: NGC 5907 Member No.: 430	MOONS IN PERSPECTIVE -------------------- Two of Saturn's battered, icy companions hover here in this Cassini image, above the planet's ringplane. To get a sense of the three-dimensional nature of the scene, note that the wide band of visible rings is in between the two moons in this view. Mimas is outside the far side of the rings. Dione is outside the rings and closest to Cassini. http://spaceflightnow.com/cassini/060123moons.html -------------------- "After having some business dealings with men, I am occasionally chagrined, and feel as if I had done some wrong, and it is hard to forget the ugly circumstance. I see that such intercourse long continued would make one thoroughly prosaic, hard, and coarse. But the longest intercourse with Nature, though in her rudest moods, does not thus harden and make coarse. A hard, sensible man whom we liken to a rock is indeed much harder than a rock. From hard, coarse, insensible men with whom I have no sympathy, I go to commune with the rocks, whose hearts are comparatively soft." - Henry David Thoreau, November 15, 1853

ljk4-1 View Member Profile	Jan 30 2006, 06:39 PM Post #5
Senior Member Group: Members Posts: 2454 Joined: 8-July 05 From: NGC 5907 Member No.: 430	Three moons, quite artistic/epic: http://saturn.jpl.nasa.gov/multimedia/imag...8/N00049538.jpg -------------------- "After having some business dealings with men, I am occasionally chagrined, and feel as if I had done some wrong, and it is hard to forget the ugly circumstance. I see that such intercourse long continued would make one thoroughly prosaic, hard, and coarse. But the longest intercourse with Nature, though in her rudest moods, does not thus harden and make coarse. A hard, sensible man whom we liken to a rock is indeed much harder than a rock. From hard, coarse, insensible men with whom I have no sympathy, I go to commune with the rocks, whose hearts are comparatively soft." - Henry David Thoreau, November 15, 1853

Posts in this topic

David Saturnian Moon Identification Oct 6 2005, 02:57 PM

Bjorn Jonsson Tethys: Ithaca Chasma and the huge Odysseus crater... Oct 6 2005, 04:58 PM

Jyril Rhea is hardest to identify, since it lacks promin... Oct 6 2005, 05:23 PM

volcanopele Tethys: smaller than Rhea, rugged terrain, Odysseu... Oct 6 2005, 05:32 PM

ljk4-1 That Cassini probe sure knows a photo op when it s... Nov 11 2005, 02:55 PM

ljk4-1 MOONS IN PERSPECTIVE -------------------- Two of... Jan 25 2006, 05:22 PM

ljk4-1 Three moons, quite artistic/epic: http://saturn.j... Jan 30 2006, 06:39 PM

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