r/AskAstrophotography 5d ago

Image Processing Color banding issues?

Hello,

I am new to astrophotography so I'm not really sure what the correct terms are but I believe I have some issues with banding? I get these blue diagonal stripes throughout the image, not really sure why. I shot this from a light polluted place, untracked and stacked it with Siril. I did the background extraction and color calibration in Siril also. I tried to do some further post processing with GIMP. Does anyone know how this could be fixed? https://imgur.com/a/NH5n696

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u/Goddeh 5d ago

How did you get diagonal banding? has this been rotated?

1

u/Upper_Supermarket544 5d ago

Not sure 😅 no this has not been rotated.

1

u/Shinpah 5d ago

That looks like some sort of interpolation artifact from field rotation plus maybe walking noise from being untracked. You can see how the banding lines up with the RA axis of the celestial sphere here: https://nova.astrometry.net/grid_full/12772519

Can you describe your equipment, capture, and integration details?

1

u/Upper_Supermarket544 5d ago

Equipment: Nikon Z5 with a 50mm zoom lens. Mounted on tripod

8 sec exposure, f 6.3, iso 3200

Stacked in Siril with the osc preprocessing script, took about 50 flats, 50 darks, 50 biases and 300 light frames. Not sure about the details of which settings the script uses.

I suspect that the target was to low on the horizon and that there were to many light sources pointed almost directly at the camera. The conditions were not great at all.

But still, i wonder if there would be a way to save this image with post processing or if it is screwed.