Using FFT to remove Newton Rings in solar image?

[merlin66]

Fabio,
Unfortunately with my camera/ barlow combo I get NR in my solar images.
Usually I tilt the camera to reduce them..
I saw the FFT function and according to the manual it could/ should help remove these NR.
When I try the FFT, the FFT screen generated doesn't show the NR (in the example in the manual they are clearer..)
On the assumption we can get a FFT image - how exactly do you use the pixel correction to remove them??
The attached image is a jpeg reduction of a 2.7Mb fits image....

[fabdev]

Hello, the FFT can detect and correct a pattern only if it's present on the whole image, but here unfortunately it's present only on a side of the sun.
I cannot imagine any automatic processing which could correct something like that..

[merlin66]

Fabio,
Bumma!
Worth asking the question though......