ASI178MM Pro different Dark background levels with same settings

joetaiga

Hi,
I'm using a ASI178MM Pro for Deepsky.

I recognized that my darks do not fit anymore if the camera was disconnected between lights session and recording darks - even if using same settings and same chip temperature. It seems that at least the background level is different.

I found a post in CN where this problem was stated as well:
https://www.cloudynights.com/topic/528663-calibration-problems-with-zwos-new-cmos-cameras/

What exactly is causing this issue and how can it be avoided?

Thanks & regards
Joe

joetaiga

I did some more investigations...

The signal level of the amplifier glow is in the darks about 3 to 5 times higher than in the lights. Unfortunately it's not in each corner the same factor so it is not possible to simply scale the darks. I'm wondering how such a difference could come from a recalibration. This would make the cooling of the camera more or less useless.

I recorded the lights with USB2. Unfortunately I had a disconnect next morning and was not able to reconnect with USB2 again (this is an issue I have regularly, the camera I can reconnect with USB3 but even than the USB hub of the camera is not working anymore). Even the day after it was not possible to reconnect with USB2 so that I made the callibration frames with USB3. I remember an earlier session where I had similar problems with the darks. Here I had the same issues with a disconnect on USB2. I had a session over two days so that I took darks after the disconnect with USB3 right before I took the rest of the lights with USB3. The lights with USB3 could be callibrated with the darks but not the lights I took the night before with USB2.

But again...it's a difference of a factor. Can this be caused just by recording with USB2 and USB3?

Best regards
Joe

Tech@ZWO

joetaiga
Hello,
Please try different cables and computer to narrow it down.