The QHY268C is a cooled, back-illuminated, color CMOS camera based on the Sony IMX571 sensor with native 16-bit A/D and 3.76um pixels.
The Sony IMX571 sensor has on-chip 16-bit A/D for highest resolution of greyscale. The output is real 16-bits with 65536 levels. Compared to 12-bit and 14-bit A/D, 16-bits provides higher sampling resolution. At high gain, the camera yields close to 1e-/ADU with no sample error and low read noise.
One benefit of the back-illuminated CMOS structure is improved full well capacity. This is particularly helpful for sensors with small pixels. Even with unbinned, the 3.76um pixels of the QHY268C has a full well capacity of 51ke-. QHY268C also offer a unique read mode up to 75ke per pixel.
The QHY268C has only 0.7 electron of read noise at highest gain and 6.8 FPS at full resolution readout speed. One electron of read noise means the camera can achieve a SNR>3 at only 4 to 6 photons. This is perfect performance when conditions are photon limited, i.e., short exposures, narrow band imaging, etc., making this large area sensor ideal for sky surveys and time domain astronomy.
The back-illuminated Sony Exmor sensor has about twice the QE of similar front illuminated sensors. In addition the dark current is only 0.0005e/pixel/sec @ -20C. In general, a fan-blade mechanical shutter may fail after several hundred thousand cycles and is subject to intermittent problems in very cold weather. The advantage of an electronic shutter over a mechanical shutter is high reliability and stability when the observer takes a large number of images.
In order to get smooth uninterrupted high speed transfer of data, the QHY268C has a large 2GByte DDR3 memory buffer.
USB3.0 interface. 6.8FPS
The small pixels and round camera body of QHY268C plus the APS-C size sensor make the QHY268C an ideal match for the HyperStar and RASA optical systems.