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ZWO ASI290mm - Brand new and showing vertical bands


CKemu

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Recently purchased a the 290mm through FLO and broke the astronomers curse by actually having a clear day to use it within the same week of purchase! Madness!

However whilst taking it for a test run on my Coronado Solarmax II 60 (BF10) I discovered that upon stacking and normal processing the sensor displays vertical bands every other pixel, they aren't solid, but it's as if the chip is reading every other column as darker on average.

This happens with or without gain, independent of number of frames stacked, or software used, attached is a "raw" image and one that's had levels and a sharpen applied. It shows faintly in the raw and obviously enhanced with the sharpen.

I have also attached one that's 5x zoom, just for clarity and detail.

I have checked all software/drivers, they're current and tried different USB ports with no change in results.
Did a little research and found about 4/5 of the way down in the following link, the page talks about pixel response non uniformity. http://www.astrosurf.com/buil/CMOSvsCCD/index.html - But I would not have expected it to be this apparent, and so badly interfering with processing/the image.

I've posted on the ZWO support forums, and await a response - but thought I'd share here for discussion and thoughts.

FireCapture v2.6 Settings
------------------------------------
Observer=Chris Kennedy
Location=Cornwall
Scope=Coronado Solarmax II
Camera=ZWO ASI290MM(80453643)
Filter=L
Profile=Sun
Filename=Sun_112444.ser
Date=150219
Start=112414.267
Mid=112444.274
End=112514.281
Start(UT)=112414.267
Mid(UT)=112444.274
End(UT)=112514.281
Duration=60.014s
Date_format=ddMMyy
Time_format=HHmmss
LT=UT 
Frames captured=338
File type=SER
Binning=no
ROI=1936x1096
ROI(Offset)=0x0
FPS (avg.)=5
Shutter=100.0ms
Gain=15 (2%)
Brightness=1 (off)
AutoHisto=75 (off)
AutoGain=off
FPS=100 (off)
AutoExposure=off
SoftwareGain=10 (off)
USBTraffic=100 (off)
Gamma=50 (off)
HighSpeed=off
Histogramm(min)=29
Histogramm(max)=219
Histogramm=85%
Noise(avg.deviation)=n/a
Limit=60 Seconds
Sensor temperature=22.6°C

Sun_112444_g4_ap1907-5x.png.d1046ca0f2b6debf98257fce3beb15cb.png

Sun_112444_g4_ap1907withlevels-sharp.png

Sun_112444_g4_ap1907.png

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Don't think you need to be concerned with this - this is something that flats can easily remove.

I've found similar thing with my ASI1600 - but not in form of vertical stripes - more like checkerboard pattern.

Here is H alpha flat (not solar, but regular Ha filter for night time imaging):

image.png.d72eb1474cd58773ddaa23b3e5d818ff.png

Pattern is readily shown, but it calibrates out with use of flats.

I think such artifacts are consequence of manufacturing process - micro lenses or something else when creating sensor on silicon can lead to this. Even additional circuitary between pixels - maybe not each pixel is exactly the same size - some of them might have small part of pixel dedicated to integrated circuits for readout or amp stage.

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On 16/02/2019 at 12:45, vlaiv said:

Don't think you need to be concerned with this - this is something that flats can easily remove.

I've found similar thing with my ASI1600 - but not in form of vertical stripes - more like checkerboard pattern.

Here is H alpha flat (not solar, but regular Ha filter for night time imaging):

image.png.d72eb1474cd58773ddaa23b3e5d818ff.png

Pattern is readily shown, but it calibrates out with use of flats.

I think such artifacts are consequence of manufacturing process - micro lenses or something else when creating sensor on silicon can lead to this. Even additional circuitary between pixels - maybe not each pixel is exactly the same size - some of them might have small part of pixel dedicated to integrated circuits for readout or amp stage.

Thanks for that, flats I'd considered for dust etc, but removing the vertical stripes I'd not considered, need to figure out how to take a solar flat, but otherwise this does seem like a reasonable solution. I am surprised at the "intensity" of the column response every other line - seems excessive/abnormal, so still waiting upon ZWO to make a response on their support forum.

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  • 6 months later...

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