New ASI533MC-P Dark frame artifacts

BenBret-1

Last December I've got my first ASI533MC-Pro which had Cooling interruption issues and where finally ZWO agreed to replace it by another one.

Last Friday I've got the replacement unit from the Astronomy store where I've purchased the first 533MC-P, and this weekend i started to make my new dark library.

One thing that I've noticed on new dark frames captured by the new camera , was like strange artifacts that i never seen before with the previous unit.
These light streaks or spots are present on about 40% of the captured frames done at different exposures length (60,120,180 and 300 secs ) all done at Gain 101 and sensor cooled at -10C .

I first though it was a kind of light leaks artifacts, but it doesn't seems to be the case.
Just to make sure I've put the Camera in the refrigerator where there is no light , plus I've taped the red Power leed on the camera to make sure there was no light at all, but I'm still getting those light

Is it something that i must be concerned with or it should be considered as normal?

I'm just asking because as i said before with the previous camera i never got that kind of strange artifacts, at least not visible like this.

Thanks

Ben

Tech@ZWO

BenBret-1 It is random hot pixels, and it is normal, also might have something to do with the power supply, you can try another one.

Eriktim82

That's normal. Just take dark frames

BenBret-1

Eriktim82 You just took dark frame and you've got the same result , or you're telling me to take dark frame ???

P.S. All the above pictures were dark frames , so yes i took plenty of dark frames .

BenBret-1

Tech@ZWO Tested with th same power supply as I used before with the 2600mc and the previous 533mc-P ( same equipment), and powered from an APC battery pack to regulate the power and to an ZWO AC/DC 12V adaptor. I tried 3 differents ac/dc 12 power supply , 2x 12v 5A ZWO or 1x 12v 10A Pegasus 12v adaptor, or directly powered from the AAP and always getting same artifacts. I also tested 3 others zwo usb cables and 1 other shielded usb cable with the exacte same result.

So it's not comming from the power source or the USB cable.

bulrichl

Tech@ZWO

Tech@ZWO It is random hot pixels, and it is normal, also might have something to do with the power supply, you can try another one.

No, this has nothing to do with hot pixels.

The images of the OP contain "cosmic ray" artifacts. Cosmic ray artifacts are random. They are caused by high-energy particles that leave marks in images, also in dark frames (i.e. the particles are capable of pervading a cap or the camera housing). The number of such artifacts increases with exposure time, so it is rather unlikely to see cosmic ray artifacts in bias frames. Very high-energetic particles can even damage a photosite of the sensor.

Provided that a sufficient number of images is integrated, cosmic ray artifacts will be rejected in image integration when pixel rejection is appropriately adjusted.

Bernd

BenBret-1

Thank you for that clear explanation.
I'm pretty much getting the same amount of those light streaks at any exposure length.
Even on a 5 seconds exposure, I'm still getting these artifacts.

It's weird that i never got those line streaks with the preview 533 and also on the 2600mc !

Is it something that I should be worried about , because as I said may be 30% of my darks frame are affected .

Thanks