Rev 177 Dec 16th - Dec 29th, Rhea flyby Options

[jasedm]

Latest article is up

The highlight has to be a sub-25,000km flyby of Rhea on 22nd December, with ISS observations yielding 140m/pixel resolution at closest approach. 3 sets of mosaics are planned, focusing on the North pole and the trailing hemisphere.

Rhea's north pole has had relatively low-res coverage up until now, so this will be interesting.

[Ian R]

Rhea's north pole got some half-decent coverage from Voyager 1, didn't it?

Here's something I haven't contributed to UMSF for a while — a RGB composite of Titan:

[jasedm]

Rhea's north pole got some half-decent coverage from Voyager 1, didn't it?

You're right Ian - I was forgetting that Voyager 1 passed by Rhea at around 60,00km (32 years ago!!!) and achieved some very decent coverage on the north polar regions. Our very own Bjorn Jonsson worked up a lovely mosaic from the data on this very forum 4 years ago, see here

Will be interesting to see how the imagery compares, as Cassini's cameras are much better

Looking forward to it!

[Bjorn Jonsson]

Will be interesting to see how the imagery compares, as Cassini's cameras are much better

In addition, the sun is now almost 17 degrees north of Rhea's equator whereas during the Voyager 1 flyby it was only ~4 degrees north of it.

[elakdawalla]

Wow, it's astonishing it's been so long since equinox.

[Ian R]

This vintage animation from 1980 is a pre-encounter simulation of what Voyager would see as it passed over the moon's north pole:

http://youtu.be/zd9TOvFelFg?t=1m50s

[Floyd]

Fantastic images of Rhea available. Images for three mosaics including north pole and trailing hemisphere. Hope some of of the new members who only follow MSL take a look at what unbelievable images are coming from Cassini.

[scalbers]

The raw images website looks to have data up to just past closest approach. Hopefully there will be more from the outbound leg that should be best for mapping purposes near the north pole.

EDIT 2300UTC: Some of these are now in up to 90000km outbound range.

[Astro0]

Christmas afternoon, full stomach, lazing around, the internet and Photoshop...
Ahhh.... relaxing with Cassini images: Dione animation



Large version here: 6.35mb

[scalbers]

From what I can tell Rhea's north pole is lower left of the center in this image, with the prime meridian extending to its right...

http://saturn.jpl.nasa.gov/multimedia/imag...6/N00199606.jpg

[Ian R]

Nice animation, Astro — here's a slightly enhanced R/G/B view of Dione from the same dataset:

[titanicrivers]

Playing with a few more raw images of Titan from Rev 177 taken on Dec 27th. These were part of the TMC (Titan cloud monitoring) campaign. A hazy CL1 CB3 image presents familiar surface features that the Celestia Program helps identify. Photoshop Elements was used to make an RGB color image from raw images taken the same day. (Emily had a nice tutorial for this a couple of years ago, although I could only find the Photoshop CS3 tutorial on the Planetary Society website).

[scalbers]

Happy New Year,

I was able to fill in some northern areas as can be seen on this map of Rhea:

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

Steve

[Floyd]

The poor dragons are confined to such a small patch--will any future Cassini imaging banish them completely--or are they safe until a future Saturn mission?

[jasedm]

Thanks Steve for your map update.

Floyd, After a quick scan of the published sources, it appears that the best chance to fill that imaging gap (and thus vanquish those dragons) is a March 9th targeted flyby this year, with closest approach (c/a) at just under 1000km.

Cassini's orbital inclination remains high (57 degrees) so the spacecraft will be looking 'down' towards Rhea's north pole which is fairly-well illuminated by the sun.

I suspect (but don't know for sure) that gravity measurements may be the priority at c/a, but I'd be amazed if there weren't some pretty spectacular high-res images planned for the outward-bound leg of the encounter. (approach is from the night-side)

Subsequent to this, I suspect we won't be seeing Rhea's north pole in greater detail for a half-century or so...

Jase