[X] My Assistant

[dilo]

I do not know is only my impression, but in the most recent wide and narrow angle images I noticed a lot of diffraction features, probably caused by increased amount of particles on the front lens... they are more noticeable in uniform, low contrast images; see for example:
http://saturn.jpl.nasa.gov/multimedia/imag...1/W00006832.jpg
Do someone has an explaination to this?

[volcanopele]

We are planning to take CB3 filter flats in August. We plan to do this by imaging titan while slewing, this creating a smeared image. Do thing several times, average, and you got a decent flat, hopefully.

[dilo]

We are planning to take CB3 filter flats in August.  We plan to do this by imaging titan while slewing, this creating a smeared image.  Do thing several times, average, and you got a decent flat, hopefully.

Hi, Jason.
For sure, flat fields you are talking should greatly improve narrow cam images like this:
http://saturn.jpl.nasa.gov/multimedia/imag...0/N00032718.jpg
(I noticed that dark spot on the left became clear in MT1 filter:
http://saturn.jpl.nasa.gov/multimedia/imag...eiImageID=38212, so probably is necessary to make flats also in other bands...)

Anyway, first image I posted was taken with clear filter by widecam and, as already noticed by Gary, it would be hard to remove them with a simple flat field:
http://saturn1.jpl.nasa.gov/multimedia/ima...1/W00006834.jpg
Looking carefully to this image, many features are also duplicated toward left/bottom, and shift depends from their diameter (=distance from focal plane). Moreover, comparing it with with other two similar images taken immediately before (W00006832/33), I discovered that diffraction rings change in luminosity and translate in position, probably due to different lighting conditions! see following composition where each image is associated to an RGB channel:

So situation is even more complicated than previously thought, probably due to multiple light reflections!!
Jason, do you know if there was a discussion on this item inside ISS team and if they planned to use some kind of software in order to simulate/remove it???
Thanks.