Dione Image Products Options

[scalbers]

Jase,

Thanks for the heads up, the new image indeed fills in northern areas in my map:

http://laps.noaa.gov/albers/sos/sos.html#DIONE



Kind of neat with the solar declination close to zero now and going towards positive.

Steve

[ugordan]

Here's a revisited Dione crescent mosaic from October 11, 2005. Official release is here. Due to the substantial amount of saturnshine present (remember, the flyby was low phase inbound with Saturn as backdrop so practically a "full" Saturn illuminates Dione's nightside here), there's a lot of detail present on the nightside, but it's lost in the official version.



Sunstruck WAC frame for context:

[jasedm]

Magnificent Gordan.
Your version of the hi-res crescent shows unequivocally how icy the surface actually is, rather than being composed mostly of silicates.
It's easy to forget that these moons, were they orbiting closer to the sun, would have surfaces covered with water oceans.

[antipode]

Wow! Not only that, but look at that looooong slump face near the terminator - there are two large craters that have been so neatly sectioned in half they look like illustrations out of a book!

P

[Hungry4info]

It's easy to forget that these moons, were they orbiting closer to the sun, would have surfaces covered with water oceans.

Wouldn't the water just boil instead of becoming liquid? The idea of a liquid ocean on these moons implies an atmospheric pressure suitable to allow water to exist in a liquid phase.

If Dione were near the sun, I would expect it to resemble a giant comet instead.

[jasedm]

Yes, I'm sure you're correct H4I - I neglected to account for the atmospheric pressure....

[Explorer1]

It would have to be large enough to have enough gravity to hold on to an atmosphere. Other than Titan (rather obviously) only Ganymede has enough mass to hold on to one, correct?

[volcanopele]

It would have to be large enough to have enough gravity to hold on to an atmosphere. Other than Titan (rather obviously) only Ganymede has enough mass to hold on to one, correct?

Yes and no. Keep in mind that surface temperature plays a role. In general, the higher the temperature, the faster the molecular speed. At Ganymede, that speed is faster than the escape velocity. At Titan, it isn't.

[DrShank]

Wow, that crater left quite a splat! Great work, Ugordan!

That splat is also visible in my color ratio maps and in stephans recent dione paper. Creusus is the name i think. nice to see the global view too!

[JohnVV]

that is a good "splat" all right
a few views from a mesh in blender
[attachment=21615:Screenshot_4.png][attachment=21614:Screenshot_3.png] [attachment=21616:Screenshot_5.png][attachment=21617:Screenshot_6.png] [attachment=21618:Screenshot_7.png]
and a bump map - dem
[attachment=21619:di.png]

[Hungry4info]

Other than Titan (rather obviously) only Ganymede has enough mass to hold on to one, correct?

All four Galilean moons have tenuous atmospheres. Triton and Luna as well.
All of them except Triton, if I recall correctly, are constantly replenished (else they would quickly leave).

[volcanopele]

That splat is also visible in my color ratio maps and in stephans recent dione paper. Creusus is the name i think. nice to see the global view too!

Creusa. The flyby during Rev129 also provided some great views of that crater as well.

[machi]

My first hi-res Dione (at 72 m/pix).
Filters IR3+GRN+UV3.

Attached thumbnail(s)

 

[ugordan]

Heh, you have a good eye! I picked that exactly the same footprint to single out a while ago. Never did get the willpower to do the whole globe, but the lighting in this one seemed the best. Looks like I managed to upload a mirror image somehow - if it weren't for you I'd never figure it out

[machi]

So this is funny
I controlled all your images, which I downloaded to my computer and I thought, that you haven't this.
Another interesting thing - We both used same image orientation!