[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 & ????

[JTN]

Does anyone know the three moons in this grouping:
http://saturn.jpl.nasa.gov/multimedia/imag...eiImageID=62180
Rhea, Mimas & ????

FWIW, here's a quick'n'dirty animation of the frames around this one (N00049532-N00049570).
(There are some earlier ones, N00049514-N00049531, but with them there'd be a jump in the animation.)

BTW, your analysis tool does a nice job on these.

[jmknapp]

BTW, your analysis tool does a nice job on these.

Yeah, when I asked the question I hadn't finished that tool yet, & it wasn't reporting Enceladus due to a bug! (thanks, ugordan.)

Nice animation! Now that I got the simulated ISS viewer going, I'll try to make a smooth simulated animation of what the NAC saw during this mutual event. Should be interesting...

[ugordan]

Now that I got the simulated ISS viewer going, I'll try to make a smooth simulated animation of what the NAC saw during this mutual event. Should be interesting...

Outstanding work, Joe! You even simulate saturnshine (pretty accurately, too!). The only thing that comes to mind that would make your simulator even better would be a bit of antialiasing to remove the jaggedness of the limbs and textures, but it outclasses the JPL Solar System simulator already -- it doesn't do saturnshine.

A question, though -- there seems to be a slight shift in the predicted and observed positions in both your and JPL simulator. Is this due to the problem of calculating the exact time from a not-so-accurate distance (you mentioned this before, IIRC) or a problem in ephemerides?
I'd venture to say it's the former - I can't imagine Cassini coming to within 175 km of Enceladus with such prediction errors?