[X] My Assistant

[ugordan]

A great Rhea multispectral set recently came down, taken from a distance of around 245 000 km. Here's a RGB composite, Rhea really fills the NAC field of view in this one:

[David]

A great Rhea multispectral set recently came down, taken from a distance of around 245 000 km. Here's a RGB composite, Rhea really fills the NAC field of view in this one:

What's the straight line slanting across the lower-left-hand quadrant? Surface feature or image artifact?

And doesn't Rhea have some pretty darn huge basins, even if they are in low relief?

[ugordan]

What's the straight line slanting across the lower-left-hand quadrant?  Surface feature or image artifact?

No, that's not an image artifact. A similar feature was seen in images taken months ago, see this CICLOPS release. I believe the feature itself is curved, but the viewing geometry makes it look straight. It's interesting that two different views produce a straight line, though I don't know if it's the same feature -- Rhea might have more than one of these linear features.

EDIT: On closer inspection, it turns out the above composite image and the CICLOPS release have a remarkably similar viewing geometry, that is, sub-spacecraft point. The only thing different is the illumination angle so it's not at all surprising the feature turned out to be straight in both images. Ted Stryk's larger image also shows the linear feature and due to a different viewing angle it's clear that it is in fact curved.
Talk about interesting coincidences...

[jmknapp]

Does anyone know the three moons in this grouping:

http://saturn.jpl.nasa.gov/multimedia/imag...eiImageID=62180



Rhea, Mimas & ????

[ugordan]

Does anyone know the three moons in this grouping:

Rhea, Mimas & ????

Enceladus.
JPL Solar System Simulator gives this result, obviously a couple of minutes after the Cassini image was taken.
Enceladus is the one more illuminated by saturnshine and farther from Rhea in that raw image.

On a side note, the new CICLOPS release shows a really perplexing trend in releasing only grayscale images when multispectral sets were obviously taken. There were a number of color composites ("natural" and enhanced color) by us amateurs a month ago and it doesn't really take more than 15 minutes to create such a composite. It's not like they have to be scientifically accurate, the imaging team clearly stated these images are for public purposes only anyway.
Why, then, the insisting on dull grayscale images? I know the moons are really bland in reality, but give me a monotone color image over a grayscale any time. It's as though the team are releasing these images against their will so they don't even bother with cool pics most of the time.
Not that there haven't been very spectacular releases, mind you! It's just that most of the time these releases tend to be routine-ish and hardly awe inspiring...

I'm sure I'll get bashed by volcanopele for this