Titan PDS Image Products Options

[Bjorn Jonsson]

Following recent discussion in this thread on Titan's polar vortex and visible atmospheric features (including what looks like faint 'cloud belts') I decided to take a look at the PDS data. The main reason is that it's possible get get much better results for low contrast targets like Titan by using the PDS data than the raw JPGs. I found some interesting images obtained on April 19, 2011; rev 147. This rev was previously discussed here when the Titan flyby was happening.

Here is a sharpened BL1 WAC image obtained at a range of 137,000 km. The subspacecraft latitude is 0.2 degrees:



North is up. Different parts of the image have been processed with different unsharp masks. Low contrast east-west 'cloud belts' are apparent and these are definitely real features. Interestingly, they are not perfectly east-west oriented but instead appear a bit 'curved'. This is not a perspective effect and also Cassini was only 0.2 degrees north of Titan's equator.

It might be possible to squeeze even more details out of comparable VIO images. The problem is that they appear awfully mottled and my 'standard' calibration/flatfielding didn't remove this. I probably need to make extra flats to get rid of this effect.

[Bjorn Jonsson]

Here are two semi-randomly selected narrow angle RGB composites from the latest Cassini PDS release (January 1, 2014). These are approximately true color images. First this one from rev 183 on March 14, 2013:


And this one is a high phase view from rev 184 on March 19, 2013:


The color difference between the two images is real and is largely due to the change in phase angle.

And finally an enhanced version of the first image to better show the south polar collar and the limb haze: