Noise line artefact in deepsky image.

[WilliamAstro]

So I was met with this artefact of this line protruding across the image and especially horizontal lined noise as well.

Here are some details to help puzzle what is causing this problem and how to fix this.

My single exposure subs are 20 seconds. (lights and darks)

497 lights, 101 darks, 30 or 15 flats, 30 or 15 dark flats, 50-60> bias frames

a portion of the lights contained clouds and I took them out of the batch and stacked those and still same thing, used less percentage and still same thing.

I used a modified Canon 600D, Star Adventurer 2i Pro, Skywatcher Evostar 72 ED DS Pro with guiding, 2 counterweights for balance.

My assumption is that it could be labelled as 'walking noise'.

Over the course of capturing the data I needed to reframe the image back to where it had to be as it drifted slowly.

[Stefan73]

Do you dither when guiding?  Looks very similar to what I got from my 550D when I started guiding without dithering.

[alacant]

1 hour ago, WilliamAstro said:

Canon 600D,

600d, so no dark frames. Of any sort. 

Simply calibrate using a constant bias of 2048.

+1 for a 15 pixel dither between frames.

HTH

[edarter]

I have a modified 600D and went through this exact issue!! in fact that heavy band you have is in an almost identical place. Are you using DSS by any chance?
Basically I tried everything I could think of to rectify it, running the camera through DC supply, battery, different USB cables, images being copied to laptop or to SD card, cable routing, exposure lengths etc etc. I was at the end of my tether then I tried the 30 day trial of APP for stacking and the problem went away immediately. I don't profess to understand the differences in the way DSS and APP do stacking and calibration, but I have read that APP's method is quite a bit more advanced (which you would hope is the case given its payware rather than freeware!).

Ed

[Elp]

DSLRs are prone to horizontal banding. It's worth getting familiar with Siril to pre process your images prior to using an imaging editing program. After doing the above, a horizontal banding reduction within Siril may also help.

[ollypenrice]

5 minutes ago, alacant said:

600d, so no dark frames. Of any sort. 

Simply calibrate using a constant bias of 2048.

+1 for a 15 pixel dither between frames.

HTH

Agreed, though the banding is purely horizontal and it seems as if the rig was providing natural dither, so I think it may be inherent to the camera.  I think PI has a tool to remove Canon banding and there is also a tool in the Ps actions set Astronomy Tools from Pro-digital. Has this camera taken proven images before in your hands?

Olly

Ed's post crossed with mine and looks promising.

Edited November 16, 2022 by ollypenrice
Stated

[edarter]

3 minutes ago, edarter said:

I have a modified 600D and went through this exact issue!! in fact that heavy band you have is in an almost identical place. Are you using DSS by any chance?
Basically I tried everything I could think of to rectify it, running the camera through DC supply, battery, different USB cables, images being copied to laptop or to SD card, cable routing, exposure lengths etc etc. I was at the end of my tether then I tried the 30 day trial of APP for stacking and the problem went away immediately. I don't profess to understand the differences in the way DSS and APP do stacking and calibration, but I have read that APP's method is quite a bit more advanced (which you would hope is the case given its payware rather than freeware!).

Ed

Just to add though, I didn't try without dark frames, but I was dithering at the time, though subsequent revisit of the dither amount has lead me to believe that I was not dithering enough at that time. I am indeed now dithering at about the 15 mark. Still doesn't explain why the switch to APP for stacking eliminated the issue!

Edited November 16, 2022 by edarter
update

[Elp]

My 600d doesn't band that much, it works fine.

[alacant]

2 hours ago, WilliamAstro said:

Canon 600D

If the issue persists, simply 'unband' the whole sequence before registering. Then stack using a decent clipping algorithm. Siril's sequential approach is the best we've found for both the above.

Cheers and HTH

Edited November 16, 2022 by alacant

[edarter]

On 16/11/2022 at 15:19, alacant said:

 

Simply calibrate using a constant bias of 2048.

 

Do you know how this is done in APP? I'm on the calibrate tab but nothing obvious jumping out at me.

Thanks
Ed

[Clarkey]

On 16/11/2022 at 15:29, Elp said:

My 600d doesn't band that much, it works fine.

Mine does sometimes and in the same place - obviously a sensor issue. It is OK with dithering and bias though.

[alacant]

13 hours ago, edarter said:

how this is done in APP

Hi

AFAIK, it isn't. It wasn't possible for our trial version at least.

Cheers 

**EDIT. Recommendation: for ease of processing, upgrade to Siril.

Edited November 18, 2022 by alacant