Rhea does have two fine impact basins; the 375 km Tirawa and a 500km basin alongside it. This second basin was identified by Phil Stooke in re-processed Voyager 1 images:

http://www.lpi.usra.edu/meetings/lpsc2001/pdf/1074.pdf

Here's some nice pics of Tethys' stripe:

http://www.lpi.usra.edu/meetings/lpsc2002/pdf/1553.pdf

Thanks, that is cool! You can really see how libration lets us see up to 59% of the lunar surface. From the regions on the limb Earth must be slowly bobbing around and dipping below the horizon.

Thanks for that link, the maps are amazing and the surface details are so tantilizing. Our maps of Mercury are at about the same stage as our lunar maps circa early 1960's.

It'll be great when MESSENGER finally plugs the last gaps in our knowledge of the first planet!

Here's a link to a Mercator projection of Mercury's surface combining Mariner 10 data & Baumgardner's images.

http://spaceflightnow.com/news/n0005/28mercury/index.html

Radar studies also indicate that the dark area of missing data between the Mariner 10 & Baumgardner coverage contains a huge impact basin.

I wrote a piece for UK magazine Astronomy Now on Baumgardner's images some time ago; fascinating stuff. That rayed crater is perhaps one of Mercury's youngest surface features.

Baumgardner's composite images of a portion of Mercury's unseen hemisphere would fill a good chunk of that incognitia. They're beautiful:

http://spaceflightnow.com/news/n0005/28mercury/index.html

An even more spectacular view of a Saturn transit will occur on (or around) 08 April 2669 when Saturn transits the Sun as seen from Uranus and its moons.

Of course a transit of Saturn (or any other planet) can be seen at any time simply by being high above the planet's night side, but that's the transit equivalent of shooting fish in a barrel. To see such an event from another celestial body is the real prize.

Pity the great ones don't occur too frequently. The next reasonably good transit is that of Earth as seen from Jupiter on 09 July 2008. From Earth Jupiter will be seen as a totally full disc, good stuff if you wanna measure its oblateness.

Season's greetings to everyone on UMSF. I've not been a member long but am already totally impressed by the quality & quantity of material being discussed here!

Here's to 2007!

Here's another transit to look out for and not as long to wait either!

On 16 June 2061 Saturn will transit the Sun as seen from Neptune. The 3.1 billion km distant saturn appears with its rings slightly open giving the impression of an 8 arc second wide eye inlaid onto the Sun.

Have a look with Celestia.

Thanks for the extra info on the transits by Jupiter's moons, I thought they may just clip the top of the Sun's disc and they do, great!

The image I got off JPL's Solar System Simulator shows mid transit at around 17.00 GMT on 19 May 2080. Any more info would be great as I've been meaning to get around to investigating this event further since Dec 2004 when I discovered it would occur.

Thanks James! That's great!

This rare Jupiter transit was written off as a near miss, and it is from the rest of Saturn's moons, but iit'll be quite a sight from Titan. Hmm...I'll be 103, so odds are these simulated pics will have to suffice!

The Cassini spacecraft wasn't able to image the 13 January 2005 transit of Earth visible from Saturn but one of its successors may well be able to capture a view of one of the most spectacular transits of all, that of Jupiter.

I ran some calculations in 2004 and found that on the 19 May 2080 as seen from Titan (and its vicinity) Jupiter will transit the Sun. The underbelly of the giant planet will graze over the Sun’s northern tip creating an impressive 40.47 arc second dent in our star and blocking around four percent of its light.

Jupiter’s north may escape the Sun but it will be ringed by fire as sunlight is bent through its Hydrogen atmosphere towards Titan, giving valuable clues to its exact chemical composition.

This event is incredibly rare, having last occurred in 86 AD and after the 2080 event there will no repeat until the year 7541.

I used JPL's Solar System simulator to get an image of the event, but as it now only simulates up to 2025, I cannot reproduce the simulation.

Can anyone confirm that this event will occur from Titan on 19 May 2080?

In case anyone is interested, Mike Brown says the IAU received his proposal in September but he's given up holding his breath on a quick decision.

Watch this space...

Does anyone know when the IAU will assign a name to 2003 EL61 (Nicknamed Santa)?