[X] My Assistant

[ngunn]

T62 Mission Description:

http://saturn.jpl.nasa.gov/files/20091012_...description.pdf

[ugordan]

Some nice haze structure in this approach limb shot:

[nprev]

Sure is. I assume this has north up still, Gordan? Reason I ask is that I'm waiting for the north polar hood to dissipate & the south hood to form...

[remcook]

The south polar hood dissipated only just before Cassini arrived, so I'm afraid you'd have to wait another Titan season for that to happen. Polar hood will probably become stronger first.

[ugordan]

I assume this has north up still, Gordan?

It should be roughly up, yes - VP probably knows more precisely. Here's an earlier approach image - this one looks like north is precisely "up":

[titanicrivers]

Some nice T62 NAC flyby images are up in the raw images. Here's 4 of them placed on the ISS background from the ciclops looking ahead description http://ciclops.org/view/5862/Rev119. All were taken with the CL1 CB3 filter from around 260K km away.

[rlorenz]

The south polar hood dissipated only just before Cassini arrived, so I'm afraid you'd have to wait another Titan season for that to happen. Polar hood will probably become stronger first.

Right - polar hood decayed just around summer solstice -
see http://www.lpl.arizona.edu/~rlorenz/polarhood.pdf

But I don't know if it is presently strengthening (though Titan is darker in blue than it has
ever been observed to be, as I just noted in my DPS talk the other week, perhaps as a result
of the polar hood).

A new south polar hood will presumably start forming soon. Since I know some people on
the ISS team, I may suggest they do some occasional Saturnshine imaging to see if they
can see it start to form in the winter darkness.

[volcanopele]

We shouldn't need to do something that drastic for a while, maybe another year. While the south pole on the surface no longer sees direct sunlight, the upper atmosphere over the pole still sees sunlight.

I have a question though, what exactly defines the polar hood? What does a forming polar hood look like?

[remcook]

Dynamical models predict trace gases (and presumably haze) to increase in the north up to about 2014, but from those plots the south polar hood can form earlier than that I think.
I guess polar hood means that it's dark at the poles, most notably in the blue- UV. In Ralph's paper the polar hood was also dark in IR, but that doesn't seem to be the case now (?) , at least not strongly
MT3: http://saturn.jpl.nasa.gov/photos/raw/rawi...?imageID=200364
blue: http://saturn.jpl.nasa.gov/photos/raw/rawi...?imageID=200360
uv: http://saturn.jpl.nasa.gov/photos/raw/rawi...?imageID=200359

[titanicrivers]

Some additional raw images from T62 are placed on the ISS map in the graphic below. In images N00143584 and N00143604 there are linear bright features which may be cloud bands. While the southern location in N00143604, between 40 and 50 S would not be an unusual place for such, the location in N00143584, around 30 N latitude, would be very strange. (suggesting the streak is perhaps an artifact of my processing or less likely surface features lining up in the hazy ISS image.) What do you think VP?

[titanicrivers]

There was a nice post T62 flyby encounter where ISS observed a transit of the ice moon Tethys across the disc of Titan. Tethys appeared larger than it normally would against Titan since it was about 1 million kilometers (621,000 miles) closer to Cassini than Titan. The graphic shows part of the sequence with Cassini's camera centered on Tethys for each photo. I have colorized Titan and omitted some photos at the very beginning and the very end of the encounter.

[Juramike]

Titan in Methan-O-Vision from October 31 images. Zoom of N Polar region.



(Combination of CL1 CB3 (= Red), CL1 UV3/BL1 (= Green), and inverted CL1 MT1 (= Blue) filtered images)

Some banding is present in the less-methane reflecting polar layers.

Full image can be seen here: http://www.flickr.com/photos/31678681@N07/4064553466/