What is this?

[stevewanstall]

I have a ZWO ASI1600MM Pro Cooled Monochrome 4/3" CMOS USB 3.0 Deep Sky Imaging Camera. When taking  'darks' this is what appears. It doesn't look like 'hot' pixels. Any ideas?

 

 

[Craig a]

Possible cosmic ray hit?

[Adam J]

6 hours ago, stevewanstall said:

I have a ZWO ASI1600MM Pro Cooled Monochrome 4/3" CMOS USB 3.0 Deep Sky Imaging Camera. When taking  'darks' this is what appears. It doesn't look like 'hot' pixels. Any ideas?

 

 

Sensor damage, possibly a cosmic ray as noted above. If under warranty you may be able to return it. Otherwise a large scale dither will help. 

[PadrePeace]

Dithering won’t solve this appearing in a dark though. If it’s in the dark then it will be calibrated into the lights surely even if the lights are dithered.
So dither and don’t use darks is what AdamJ is saying I think.

[The Lazy Astronomer]

If it's sensor damage, then it would appear on lights too, which means it would be calibrated out by the darks, and the dither would help to restore any missing information that would be covered by that area of the sensor.

[Adam J]

9 hours ago, PadrePeace said:

Dithering won’t solve this appearing in a dark though. If it’s in the dark then it will be calibrated into the lights surely even if the lights are dithered.
So dither and don’t use darks is what AdamJ is saying I think.

Not quite. I would say dither and use darks. If the pixels are totally dead, dithering will result in the areas of the image covered by the dead pixels being statistically rejected from the stack. Darks won't solve totally dead pixels without dithering and sigma clipping or similar pixel rejection settings being used in the stacking software. 

[david_taurus83]

You need to use darks with the 1600 regardless as dithering won't remove the amp glow. Have you tried to calibrate a light frame with a master dark to see if it removes the hot pixel/pixels?