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banding on solar ha stacked

Processing Solar System Sun Help Needed
6 replies•92 views
Nick Grundy avatar
Nick Grundy avatar
Hi all, wondering if you could help me identify and recommend a process for dealing with this? I got some good solar data yesterday and haven't seen this before. So far, this is just stacked in AutoStakkert 4 -->TIF. Is this something a dark frame would remove?? (haven't ever had to try that with this setup)

optical train is (foa-60-->UV/IR cut-->Quark Chromosphere-->asi432mm)
andrea tasselli avatar
andrea tasselli avatar
Dark banding or just banding is definitely something that can be addressed by bias/dark removal but you mast have had a rather high gain to be that evident in the stacked frame which is rather unusual as typically the subject's movements within the frame lead to the banding to cancel out.
Nick Grundy avatar
Nick Grundy avatar
was using sharpcap, settings below. admittedly, was experimenting with different methods. 

Is there anything radically different about capturing darks for SER outputs? I assume this is better done via sharpcap?

[ZWO ASI432MM]
CameraSerialNumber=203252092A010900, via USB3
FrameType=Light
Pan=0
Tilt=0
Output Format=SER file (*.ser)(Auto)
Binning=1
Capture Area=1608x1104
Colour Space=MONO16
Exposure/Gain Shift=0
Temperature=40.4
Turbo USB=100
Flip=None
Frame Rate Limit=Maximum
Gain=192
Exposure=1.5010ms
Timestamp Frames=Off
Brightness=1
Auto Exp Max Gain=175
Auto Exp Max Exp MS=30000
Auto Exp Target Brightness=100
CA Reduction/Synthetic Blue=Off
Mask over exposed pixels=Off
Flip (after dark/flat)=None
Trail Width=3
Minimum Trail Length=100
Trail Detection Sensitivity=9
Remove Satellite Trails=Off
Background Subtraction=Off
Planet/Disk Stabilization=Off
Banding Threshold=20.02111189303308
Banding Suppression=19
Apply Flat=None
Hot Pixel Sensitivity=5
Subtract Dark=None
DisplayStretchEnable=1
NegativeDisplay=0
Display Black Point=0
Display MidTone Point=0.5
Display White Point=1
Notes=
ZWO Focuser (2)=40405
Focuser Temperature=30.100000381469727
iOptron CEM120,70,40,26, GEM, HEM, HAE, HAZ series and SkyHunter Mount=RA=02:32:29.9,Dec=+13:14:05 (JNOW)
TimeStamp=2024-04-28T17:20:27.8515702Z
SharpCapVersion=4.1.11824.0
StartCapture=2024-04-28T17:20:27.7927726Z
MidCapture=2024-04-28T17:21:17.9505275Z
EndCapture=2024-04-28T17:22:08.1082825Z
JDStartCapture=2460429.222544
JDMidCapture=2460429.223124
JDEndCapture=2460429.223705
Duration=100.316s
FrameCount=2000
ActualFrameRate=19.9371fps
TimeZone=-7.00
andrea tasselli avatar
andrea tasselli avatar
Just the same way you would for any other subject as long the same exposure and gain settings are kept and possibly same temperature (not really relevant for bias/very short integrations). Just add the integrated master bias/dark as fits in AS,
Nick Grundy avatar
Nick Grundy avatar
I did some review and am now suspicious of the banding supression in Sharpcap as the culprit. It's the only major difference between this SER and prior ones. 

I left this on for this SER (not purposely, which explains the lower frame rate now)

any thoughts? can this banding supression go awry like this?
andrea tasselli avatar
andrea tasselli avatar
Look at the bias. If you see banding then maybe there results are expected but ONLY if somehow solar tracking was really spot on, which I doubt is likely to be. In many many years of planetary imaging I never seen such egregious banding but OTOH I never used banding suppression (and I never would) and my main capture program is FireCapture at any rate.
Nick Grundy avatar
Nick Grundy avatar
andrea tasselli:
if somehow solar tracking was really spot on


I did finally try out their feature tracking. But I can't imagine it was that good. (seemed awfully chaotic at the time)

i've never had banding suppression on before. Will be trying again in about 30 minutes and test it out.