The new QHY461PH camera we installed back in January appears to have a defect that is causing errors when incident light flux produces ADU values (at 2x2 binning) around 33,000. It shows in the 1x1 binning data when the ADC transitions between values of 8191 and 8192 and causes the output code to jump by approximately 8000 counts. Fluxes at higher and lower ADC values look okay. At 2x2 binning this defect can cause a jump in ADU value anywhere between 8000 and 32,000 depending on how many of the binned pixels are affected.
We are currently working with QHY to resolve the problem, but in the meantime you should keep your exposures short enough to avoid accumulating flux values higher than around 25,000 (at 2x2 binning). If you have images with ADU values above this, you should carefully check your data to make sure that it is not corrupted by this glitch in the camera.
We apologize for any problems this may cause in your observations and will keep everyone up to date on how and when we hope to resolve this issue.
Thanks,
Bill F.