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New problem with banding?

Pleiades Astrophoto PixInsight ZWO ASI533MC Pro Processing Deep Sky Banding
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mBuxx avatar
mBuxx avatar
Hello, 

I am having a problem with banding.  I am not sure if its a calibration frame issue or not. I have always taken my darks/flats the same way. The only difference is now that the sun is up so early, I use the sky instead of a light panel for flats. Normally I would take my dark flats during the night, but have been taking them the morning of. Not sure If this is light leak related or not.  I am not experienced in issues like this.

Master dark is 4 months old.

This image was taken over 3 days, I processed it with the original calibration frames, and then new ones again today. Not much difference.

Processed in Pixinsight, with WBPP 1x Drizzle

**I hit this pretty hard in the curves transformation to really emphasize the issue.  It is noticeable even with minimal stretching though.



I am uploading my project to google drive, in hopes someone can see where the issue was, and possibly share their expertise with me so I can diagnose these things on my own in the future.

taken with an ASI533MC Pro
William optics Gt81

This is 3 x days @ 28 300 sec lights, 60 flats and dark flats

60 Darks

Thank you.

edited: I had to re upload just my WBPP folder because it would fail to upload my original files. I hope this is still helpful.

https://drive.google.com/drive/folders/1HCBwJoSsTvT28_GVJgTZULsM9b7-pfmJ
Helpful Respectful Engaging
SoDakAstronomyNut avatar
SoDakAstronomyNut avatar
Skip using darks or bias - not needed with the 533 - calibrate with flats and darkflats (25-30 each minimum, I use 50).

CS & GB! Kip
andrea tasselli avatar
andrea tasselli avatar
Do not heed the call in the message above. Keep using darks. They are vital to control shot noise.
SoDakAstronomyNut avatar
SoDakAstronomyNut avatar
If you use darkflats, bias and darks in IMX571-based cameras (ASI533's, ASI2400's, ASI2600's and QHY268's all use the same chip in different format/dimensions) you will overcorrect your lights and flats. There are threads on Cloudy Nights and PixInsight forum that actively discourage using darks and darkflats in post with this newer CMOS chip/camera. QHY actually advertises darks are no longer needed - they don't have amp glow and bias subs are holdovers from older CCD-based cameras and darkflats already contain the same information as bias and darkframes actually work better when they are shot the same duration/time as your flats.

Since purchasing my QHY268M PH I have not used darks or bias in PI's WBPP tool and not had any banding issues. I tried using darks and bias and they made my images overcorrected. Troubleshooting banding in QHY294 cameras was usually caused by incorrect USB speed settings or cracked USB connector in the camera.

I too have a 294M and with that camera I had to use darks & bias for correction. They are notoriously finicky chips with mottled flats and banded image issues.

These newer CMOS based cameras do not require darks/bias correction. Give it a try.

CS & GB.
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andrea tasselli avatar
andrea tasselli avatar
If you use darkflats, bias and darks in IMX571 chipped cameras you will overcorrect your lights and flats. There are threads on Cloudy Nights that actively discourage using darks and bias in post with this newer CMOS chip/camera. QHY actually advertises darks are no longer needed - they don't have amp glow and bias subs are holdovers from older CCD-based cameras.

Since purchasing my QHY268M PH I have not used darks or bias in PI's WBPP tool and not had any banding issues. I tried using darks and bias and they made my images worse.  Troubleshooting banding in QHY cameras, if it does occur, is usually caused by incorrect USB speed settings.

I too have a 294M and with that camera I had to use darks & bias for correction. They are notoriously finicky chips with mottled and banded image issues.

These newer CMOS based cameras do not require darks/bias correction. Give it a try.

CS & GB.

The OP is using an ASI533MC camera, not a QHY. As I do (but Altair) and you'd need darks if you want to minimize all sorts of temperature-related issues with the minimum of fuss. Until further info from the OP arrive I cannot comment on the source of the banding issue but let's just say that I never experienced them in any camera of mine, including the 533MC.  And I ALWAYS use darks. Easy to do, easy to use.
mBuxx avatar
mBuxx avatar
I have attatchdd the google drive.

I also started to restack excluding dark frames before I left for work this morning.

is it normal that WBPP would throw a warning with there being no darks?  I still used flats and dark flats.

I should also add I did minimum processing and the banding was still there

automatic background extraction
star removal
autostretch just to look, unfortunately still visible
mBuxx avatar
mBuxx avatar
andrea tasselli:
If you use darkflats, bias and darks in IMX571 chipped cameras you will overcorrect your lights and flats. There are threads on Cloudy Nights that actively discourage using darks and bias in post with this newer CMOS chip/camera. QHY actually advertises darks are no longer needed - they don't have amp glow and bias subs are holdovers from older CCD-based cameras.

Since purchasing my QHY268M PH I have not used darks or bias in PI's WBPP tool and not had any banding issues. I tried using darks and bias and they made my images worse.  Troubleshooting banding in QHY cameras, if it does occur, is usually caused by incorrect USB speed settings.

I too have a 294M and with that camera I had to use darks & bias for correction. They are notoriously finicky chips with mottled and banded image issues.

These newer CMOS based cameras do not require darks/bias correction. Give it a try.

CS & GB.

The OP is using an ASI533MC camera, not a QHY. As I do (but Altair) and you'd need darks if you want to minimize all sorts of temperature-related issues with the minimum of fuss. Until further info from the OP arrive I cannot comment on the source of the banding issue but let's just say that I never experienced them in any camera of mine, including the 533MC.  And I ALWAYS use darks. Easy to do, easy to use.

I also always use darks without an issue.  I have attached my google drive folder. Thank you for the help
andrea tasselli avatar
andrea tasselli avatar
So here we are: Your flat-dark looks odd with obvious banding (see yours compared with mine, near the same exposure length):



This said I haven't seen any banding in this integrated master light:

mBuxx avatar
mBuxx avatar
andrea tasselli:
This said I haven't seen any banding in this integrated master light:


I am begining to wonder if its something to do with StarXterminator , it is after that step its noticeable.
mBuxx avatar
mBuxx avatar
If you use darkflats, bias and darks in IMX571-based cameras (ASI533's, ASI2400's, ASI2600's and QHY268's all use the same chip in different format/dimensions) you will overcorrect your lights and flats. There are threads on Cloudy Nights and PixInsight forum that actively discourage using darks and darkflats in post with this newer CMOS chip/camera. QHY actually advertises darks are no longer needed - they don't have amp glow and bias subs are holdovers from older CCD-based cameras and darkflats already contain the same information as bias and darkframes actually work better when they are shot the same duration/time as your flats.

Since purchasing my QHY268M PH I have not used darks or bias in PI's WBPP tool and not had any banding issues. I tried using darks and bias and they made my images overcorrected. Troubleshooting banding in QHY294 cameras was usually caused by incorrect USB speed settings or cracked USB connector in the camera.

I too have a 294M and with that camera I had to use darks & bias for correction. They are notoriously finicky chips with mottled flats and banded image issues.

These newer CMOS based cameras do not require darks/bias correction. Give it a try.

CS & GB.

For anyone following, this was the issue.  Although I have processed tons of images this way (using my master dark library) for this one it had an issue.  I restacked without the darks and the banding had completely disappeared.