Uneven Background in ASI071MC Pro

Hi, after upgrading my AQSI071MC cool due to the sensor icing problem, I was happy with the improvement (no icing and a much lower

dark current). So I tested the camera on dim objects with gain 190 and 240. To my surprise I realized an uneven background in biasframes and

darkframes:

At gain 240 the ADU in the middle of the long frameborder is 40 percent higher than in the middle of the short border.

The effect is symmetric and "pincushion-shaped" and shows up very well in Maim DL with screen stretch level "medium".

It drops with lower gain and reaches about 3 precent at gain 0.

I remove the pattern by application of master biasframes and post my observation only to get an information on possible reasons of the effect.

My camera is connected to a notedbook (Windows 7 64 Bit, Maxim DL 5, USB 3).

Best regards, Detlef Lind

we found different sensor performs different

some of the sensor is more obvious than others

but you can calibrate it well

Thank you Sam. Your information supports my decision to keep the camra (my caera! has a dark current of only 0.00057 e/pix/sec) !

With best regards,

Detlef Lind