Resolved ST-8XME bias level change

Discussion in 'Legacy Models - Community Support' started by EricG, Mar 29, 2020.

Tags:
  1. EricG

    EricG Standard User

    Joined:
    Mar 21, 2020
    Messages:
    4
    I recently set up my observatory for the season (I put everything away for the winter as it gets too cold in this part of Canada). I noticed the bias level for my ST-8XME has changed since last fall from approximately 100 to 900 for the main CCD and 13000 for the guider CCD. Otherwise, the camera appears to function normally.

    Any idea what the cause may be? Is it possible it may be caused by software, or is it likely a hardware failure within the camera?

    Thank you

    Eric
     
    EricG, Mar 29, 2020
    #1
  2. Doug

    Doug Staff Member

    Joined:
    Sep 25, 2014
    Messages:
    10,316
    We made a change to the default settings for SBIGUDrv. There is a completely unnecessary "Auto bias level correction" feature, which sometimes causes problems with various control programs. So we now default it off.

    You can turn it back on in the SBIG Driver Checker, under Config Drv, but we recommend that you leave it turned off.
     
    Doug, Mar 29, 2020
    #2
  3. EricG

    EricG Standard User

    Joined:
    Mar 21, 2020
    Messages:
    4
    Thank you for the quick response. I will try turning off the Auto bias level correction. The camera has worked flawlessly for the past 8 years, so hopefully that solves the problem.

    Eric
     
    EricG, Mar 29, 2020
    #3
  4. Doug

    Doug Staff Member

    Joined:
    Sep 25, 2014
    Messages:
    10,316
    To be clear: the "problem" is that it is turned off. However, I'm also saying that it's not actually a problem; we recommend that you leave it turned off and accept the higher bias level. That is the camera's actual bias level.
     
    Doug, Mar 30, 2020
    #4
  5. EricG

    EricG Standard User

    Joined:
    Mar 21, 2020
    Messages:
    4
    Sorry, I misunderstood what the auto corection does.

    I then have questions on the impact on my darks library. How much variability can I expect in the bias level over time? Will I need to update my darks library frequently to account for bias changes? How often should I check the bias level?

    Thank you

    Eric
     
    EricG, Mar 30, 2020
    #5
  6. Doug

    Doug Staff Member

    Joined:
    Sep 25, 2014
    Messages:
    10,316
    The bias level should be pretty stable. We haven't had any reports of problems with calibration caused by turning this feature off.

    Of course if you choose to do so, you can turn it back on via SBIG Driver Checker.
     
    Doug, Mar 30, 2020
    #6
  7. EricG

    EricG Standard User

    Joined:
    Mar 21, 2020
    Messages:
    4
    Perfect. Thank you.

    Eric
     
    EricG, Mar 30, 2020
    #7

Share This Page