Help ASI 1600mm PRO- Darks' mean ADU unstable

[Anthony RS]

Hello,

 

I've recently had some issues with my ASI 1600mmPRO that I noticed while taking 10 minute darks at gain 200. The camera is not 1 year old yet.

 

Before I explain what I did, all the test were done in exactly the same conditions, same laptop etc... I tried using different USB cables, different capture software and a different PC with the same results.

 

My main issue is that the mean ADU of my darks are not stable. They start at ADU 920 for example, go up slowly till about 970 and then drop back to 915 or so. This does not happen at gain 75, only gain 200 (did not test other gains yet). 

 

I have plotted a graph showing the mean value of each frame for 5 minute and 10 minute darks at gain 200. The x-axis is the frame number, the y-axis is the mean value.

 

I compared these darks with my older darks, and the old darks' mean was extremely stable (+- 1 ADU difference between frames).

 

The cooler power seems to be stable with no big fluctuations (just 1 or 2% max and it rarely changes).

 

I am currently in the process of taking 3 minute darks at gain 200 to see if the same trend happens. So far the mean appears to be stable. I will update this info once capture has finished.

 

Still waiting for ZWO support to reply so I'd appreciate if anyone has any insights or if someone else had this issue just so I save myself some time and trouble.

 

Cheers,

Anthony

Edited April 18, 2021 by Anthony RS