STF-8300 change in bias level

Hi,
I have an STF-8300 that I have been using in a robotic telescope for about 3 months, although I purchased it about two years ago. The bias (offset) level suddenly changed last week from about 800 to 28000. This apparently happened spontaneously -- I did not change the drivers or fiddle with any settings, but one night it was at 800, the next night, and all successive nights since then the bias or offset level has been at 28000. This is messing up my data and so I need to get a fix for this ASAP. I expect some electronic problem and that I will have to send it in for servicing, but is there a software solution? I see in CCDops that this camera has a fixed bias level, and so presumably I cannot reset it to 800. Apart from that change in bias level there is no change in the functioning of the camera.

Richard Gray

 

What settings and how is it done?

Larry


Sent from my iPad using Tapatalk HD

 

Larry,
please wait, here is one software solution if your hardware is all right. I have to consult it with Doug first.
We will come back to you asap.
Jan

 

Larry,
you can easily set the bias value of your STF-8300 camera using CCDOPS v 5.57, build 1, provided your camera is in a good shape.
I checked the CCDOPS and found, I had already implemented this feature there, so please follow the next few steps and try it.
Attached is also screenshot of my STF-8300 bias value inside the USB Offset dialog, which does the bias measurement and saves
it to camera's EEPROM on your request.

1) Run CCDOps v 5.57, b1 or upload/install it from sbig web page.
2) From Menu go to: Edit -> Preferences... you will see a new "CCDOps Preferences" dialog window
3) Press a tiny rectangular button on the top of this dialog labeled: "Select the options you want for CCDOps"
4) A new "Command Line Options" dialog will pop up. Check the "Show Advanced Menu" checkbox, then press OK, OK buttons.
5) Now, you have an Advanced menu item on the right side of the main Menu.
6) Press this "Advanced" item and select "Set USB Offset" item to see the "USB Offset" dialog window we are interested in. Please note, your camera has to be
connected to your PC and turned ON and possibly link should be established. You can turn your camera ON just in this point 6 or whenever sooner.
7) You will see "Active CCD : Imaging ", so press "Start" button to measure the bias of your CCD. You can repeat it
many times, just to see how it varies. In my case, it is around ADU = 950 - 1030, see my attachment. The default bias value of all of SBIG
cameras is around ADU = 1000, so if you see something like this, simply write this value to the EEPROM inside your camera.
If you still see something like ADU = 28000, your camera is probably broken and you should contact Repairs - Bill Lynch: (805) 308-6979
bill@sbig.com.

So, good luck...
Jan

 

Thanks for the info guys. The Bias level for my camera showed 1008.

Larry