Bias Shift - How Can I Tell if My 16803 is Exhibiting This?

Some of my recent calibrated images are coming out very 'spotty' and black and white with no shades of grey. Someone mentioned that it might be bias shift and something to be solves with a different pedestal value or perhaps overscan processing. I'm not familiar with either one of these.

How can I tell if I'm having a bias shift problem? Is this something you can tell from analysis of sample bias and dark frames?

Thanks for your help.

-Lloyd

 

I don't know how to do that from my Mac.

Here's a DropBox link: https://www.dropbox.com/sh/4fybuuvkt9qj7fx/AAClgg8S3smz54D6KhZwFODBa?dl=0

There are 2 bias from different times.

Thanks, Doug.

-Lloyd

 

Any thing else I can provide to get clarity on this? Thanks.

 

After nearly 4 weeks can I get some guidance on this question?

I'm the same guy with 2 16803s, one from a highly questionable source that I'm stuck with and lighter in the wallet by $10,000 and one brand new one directly from you (no middle man). Neither one of them are performing the way they're supposed to be. Maybe that should be x2 = $20,000 that is currently providing no value.

The issue now has escalated to include dust that will not calibrate away and leads to even more questions that I'll pose here, but am glad to pose individually if it should make communications more timely...

1. What is the recommended flat ADU? I've measure the linearity to get an estimate of this, but what is the official suggested value?
2. What is the "air path" to the cover glass other than the telescope aperture in the case of an uncorrected RC with a filterwheel and an AOX between the outside and the exposed chip? In other words, how can dust get into the camera and onto the cover glass?

All these issues conspire to make both cameras unusable.

I just need guidance and / or a testing protocol.

Thank, you.