Any idea what's causing this?

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Ken Potts avatar
I've been seeing this in my images lately when I zoom in. I can't figure out if it's an acquisition issue or a post processing issue.  Any help would be much appreciated. 


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Tony Gondola avatar
It's walking noise and it's very common. It happens when you have drift in combination with little or no dithering.
Obdulio Garcia-Nicolas avatar
Dear Ken.

I agreed with what Tony Gondola just pointed out as a source of this walking noise, not enough dithering. I hope you can correct it in the next imaging sessions.

CS,

Obdulio
Ken Potts avatar
Thank you so much Tony. I guess I need to incorporate dithering into my plan.
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Obdulio Garcia-Nicolas avatar
Also take into account that dithering is needed if you want to drizzle your images, otherwise there is not a real benefit from drizzling. 

CS
Brian Puhl avatar
There's never a time when dithering is NOT needed for DSO imaging.   

On a side note, don't throw away your old data, just incorporate that data in with dithered data, at some point, all the walking noise will disappear.   I'd say you'll need to double your current integration just to offset however.
andrea tasselli avatar
Obdulio Garcia-Nicolas:
Also take into account that dithering is needed if you want to drizzle your images, otherwise there is not a real benefit from drizzling. 

CS

No, it is not. What it is needed is random non-integer shifts between each data set (an image). How do you achieve those is up to you.
Ken Potts avatar
Awesome, thanks everyone for the advice and help! Really appreciate it.
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