[X] My Assistant

[Decepticon]

Another flyby coming soon. Interesting observations include radar swath of Huygens landing site.

Just before CA. http://space.jpl.nasa.gov/cgi-bin/wspace?t...porbs=1&brite=1

From above... http://space.jpl.nasa.gov/cgi-bin/wspace?t...porbs=1&brite=1

I really missed VP encounter updates So I tried my best at showing the Hemisphere to be imaged during the flyby.

[tfisher]

Okay, one final attempt for me. This time I stacked three CB3 images to improve the signal-to-noise ratio in the green channel and I was much more gentle with the adjustment curves so Tui Regio isn't so exaggerated. There is a bit of a rainbow effect, which I think is different atmospheric illumination for the different wavelengths, but I think the coloration that differentiates Tui from the rest of Xanadu is definately real.

[jmknapp]

Okay, one final attempt for me.  This time I stacked three CB3 images to improve the signal-to-noise ratio in the green channel and I was much more gentle with the adjustment curves so Tui Regio isn't so exaggerated.  There is a bit of a rainbow effect, which I think is different atmospheric illumination for the different wavelengths, but I think the coloration that differentiates Tui from the rest of Xanadu is definately real.

Out of curiosity, what kinds of geometrical tweaks do you do on the different images? Seems like since they are taken in sequence there will be slight scaling, translation and perspective differences?

[tfisher]

Out of curiosity, what kinds of geometrical tweaks do you do on the different images? Seems like since they are taken in sequence there will be slight scaling, translation and perspective differences?

These required a tiny bit of rescaling and a few pixels of translation. Cassini doesn't usually rotate (someone described it as "like a tripod in space") so at least that reduces by one the degrees of freedom needed for alignment. I think actually I only rescaled the two CB3 images that were taken a little while away from the rest of the sequence. I'm doing it all by eye, of course, which on Titan means trying to line up the coastline and islands as well as possible.

To decide how much to rescale, I crop the two images so there is no extra space around the edges, view them together in an overlay mode (either red+green or difference of gray scale images), then count the pixels required to slide the smaller image so features on the left edge line up to where features on the right edge line up. I enlarge the smaller image by that many pixels, and realign again. If it doesn't look quite lined up I repeat.