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Image Banding


(@thedwo)
White Dwarf Customer
Joined: 3 years ago
Posts: 15
Topic starter  

My recent set of images, taken with ASI294MC-Pro camera using NINA, show significant banding when processed via APP. I have over stretched these to highlight these artifacts.

Any advice as to what may be causing this is appreciated.

PelicanA
ElephantsTrunkA

 


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(@astrogee)
Red Giant Customer
Joined: 4 years ago
Posts: 128
 

Well I guess that's bias noise. You can calibrate out with bias frames. I have a 294 and I don't think I have much bias noise - lots of amp glow though. When I capture I have the offset set to 8, this setting was automatically selected by my capture software AstroImager (Mac product)


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(@thedwo)
White Dwarf Customer
Joined: 3 years ago
Posts: 15
Topic starter  

Thanks for that comment I'll check it out. I have also been advised that the culprit could be USB-3 bandwidth, where too many devices are calling for access at same time.

Cannot check properly until some clear skies return - and who knows when that will be ;-((

 


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(@astrogee)
Red Giant Customer
Joined: 4 years ago
Posts: 128
 

I don’t know who told you that but that’s not how digital communications works. All transferred data is verified to be valid and complete. What you see is in the image you took. Bad communications would cause lost data. Not noisy data. 


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(@mestutters)
Red Giant Customer
Joined: 5 years ago
Posts: 137
 

Hi Frank,

I take it that we are looking at a stacked image in your screen-shot and not a single frame?   The nebula signal looks pretty weak to me so I assume you are not integrating that many frames and/or they are of short duration?

Have you tried examining your individual subs using a hard stretch with viewer in a) linear, and b) l-calibrated mode?  When switching to the l-calibrated mode, much of the noise and other unwanted artifacts in your linear subs should be removed. If this is not the case  then I would carefully review your process for capturing and stacking your calibration frames. Also try experimenting with the Cosmetic Correction options in 2) Calibrate as this may help.  Have a look at the early part of this video tutorial:

https://www.astropixelprocessor.com/complete-lrgb-tutorial-of-ngc292-the-small-magellanic-cloud-by-christian-sasse-itelescope-net-new-version-app-1-081/

Another thing you might look at is the power supply to your camera.  Is this internal battery or a converter?   I had a problem a year or two back which I eventually tracked back to low input voltage to my camera.   If camera is unable to draw sufficient power then I think you can get strange patterns in the lights which will not calibrate out.   Do you see any differences between images taken at start of your session versus the end?

best of luck

Mike

 

This post was modified 2 years ago by mestutters

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(@vincent-mod)
Quasar Admin
Joined: 5 years ago
Posts: 4727
 

It would indeed be interesting to see how a single sub looks like and if you have the proper calibration data. The noise seems very high, what gain and other settings were used?


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