Hot Pixels

[JimmyWimmy]

In my 60 frame stack of M27 there are quite a few hot pixels visible.
Is there some way I can suppress these during stacking?

HotPixels.jpg (243.76 KiB) Viewed 1130 times

[ZWO ASI533MC Pro]
FrameType=Light
Debayer Preview=On
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Tilt=0
Output Format=FITS files (*.fits)
Binning=1
Capture Area=3008x3008
Colour Space=RAW16
Hardware Binning=Off
Turbo USB=100(Auto)
Flip=None
Frame Rate Limit=Maximum
Gain=250
Exposure=15.000s
Timestamp Frames=Off
White Bal (B)=50
White Bal (R)=50
Brightness=0
Cooler Power=40
Temperature=-10
Target Temperature=-10
Cooler=On
Auto Exp Max Gain=300
Auto Exp Max Exp M S=30000
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Minimum Trail Length=100
Trail Detection Sensitivity=9
Remove Satellite Trails=Off
Background Subtraction=Off
Planet/Disk Stabilization=Off
Banding Threshold=10
Banding Suppression=0
Apply Flat=None
Hot Pixel Sensitivity=5
Subtract Dark=None
NegativeDisplay=0
Display Black Point=0
Display MidTone Point=0.5
Display White Point=1
Notes=
TimeStamp=2023-08-06T23:10:45.5960415Z
SharpCapVersion=4.0.9538.0

[Menno555]

You can counter the hot pixels like this with taking dark calibration frames.
You can either make those manually or use the SharpCap wizard for that (which is the easiest way).
For explanation of dark frames and how to make and use them, see https://docs.sharpcap.co.uk/2.9/17_Capt ... Frames.htm

Menno

[admin]

Hi,

also, to add to Menno's answer... In recent versions of SharpCap the 'Subtract Dark' dropdown has a 'Hot Pixel Removal Only' option which you can use without needing dark frames. An extra slider will appear allowing you to tune the strength of the hot pixel removal (which you should do before you start stacking, but at the same exposure/gain settings you plan to use). This mode looks for and removes pixels that are much brighter than any of their neighbours.

cheers,

Robin

[JimmyWimmy]

Thanks both. I will try the "Hot Pixel Removal Only" method next time out.
What does the "Hot Pixel Sensitivity=5" entry in my log file mean? Is it related?

[admin]

Hi,

yes, that's the strength of the hot pixel detection. However it always gets written to the settings, even when it is not being used (ie when Dark Subtraction is set to None).

cheers,

Robin

[Tiago Ferreira]

Hi,

also, to add to Menno's answer... In recent versions of SharpCap the 'Subtract Dark' dropdown has a 'Hot Pixel Removal Only' option which you can use without needing dark frames. An extra slider will appear allowing you to tune the strength of the hot pixel removal (which you should do before you start stacking, but at the same exposure/gain settings you plan to use). This mode looks for and removes pixels that are much brighter than any of their neighbours.

cheers,

Robin

Which works like a charm...