The new QHY600 Mono Fullframe CMOS camera includes two overscan regions, one being an Optic Black Area and the other the overscan. From QHYCCD's documentation
My understanding, is that currently PixInsight is not able to read/differentiate the two regions. The new IMX455 Sensors stand to be the new go to high end AstroPhotography sensor, it would be good if PixInsight could take advantage of all the capabilities.The optic black area and overscan area is usually used for precise calibration and for the calibration without the bias frame and dark frame, or other scientific using. Due to it is an non-image area , QHYCCD does not guranttee the signal quality in the overscan area. If you do not use this area, you can select the option "ignore overscan area" in the ASCOM driver or select a ROI of effective area range in SharpCAP.