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31 July 2020 - Comet Registration video tutorial using APP 1.083-beta1 released.

30 July 2020 - APP 1.083-beta1 has been released introducing Comet processing! This 1st beta has comet registration. The stable release will also include special comet integration modes.

9 July 2020 - New and updated video tutorial using APP 1.081: Complete LRGB Tutorial of NGC292, The Small Magellanic Cloud by Christian Sasse (iTelescope.net) and Mabula Haverkamp

2019 September: Astro Pixel Processor and iTelescope.net celebrate a new Partnership!

Image Banding  

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(@thedwo)
White Dwarf Customer
Joined: 1 year ago
Posts: 13
July 13, 2020 15:12  

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)
Neutron Star Customer
Joined: 2 years ago
Posts: 104
July 13, 2020 17:38  

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: 1 year ago
Posts: 13
July 14, 2020 10:57  

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)
Neutron Star Customer
Joined: 2 years ago
Posts: 104
July 14, 2020 13:25  

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)
Neutron Star Customer
Joined: 3 years ago
Posts: 106
July 14, 2020 19:02  

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 1 month ago by mestutters

(@vincent-mod)
Quasar Admin
Joined: 3 years ago
Posts: 2128
July 17, 2020 21:29  

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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