QHYCCD QHY268c
From the company QHYCCD is this QHY268c APS-C sized colour camera. It is built around the Sony IMX571 sensor and available in a colour and monochrome version. The sensor has a resolution of 26 MP with individual pixels measuring 3.8 µm. This modern 16-bit sensor has a dual-gain design. At gain 26 the sensor gives an extra boost in dynamic range up to 13.5, the same as at gain 0. So there is not much reason to use any other setting. Noise levels are very low and sensor temperature can be cooled to about 35 degrees below ambient.
The sensor in this camera can also be found in astro cameras from other brands. The ZWO ASI2600 for example is very similar to the QHY268. Differences are in the electronics. The QHY268 can be used in different shooting modes for different situations. Also the cover glass in the QHY is anti-reflective clear glass to reduce halo-effects. It means that it should be used with a separate IR/UV cut filter. The ZWO has an IR/UV cut filter built in to cover the sensor. Both the monochrome and colour versions of this camera have become very popular astro cameras. The APS-C sensor-size is a good cost/benefit option and fits many optical systems.
For the observatory, the addition of a one-shot-colour camera is a nice addition to the monochrome cameras. Great for imaging during travel, and an almost must-have for fast moving objects such as comets.
Specifications
Resolution: 6280*4210 pixels (26 Megapixels)
Sensor-size: 23.5 x 15.7mm; 28.3mm diagonal
Quantum Efficiency: 92%
Full well capacity: 51ke (75ke in extended full well mode)
ADC: true 16-bit
Interface: USB3 (image download) and filterwheel (proprietary)
Camera size: diameter: 90mm, weight: 780g
Filters and Adapters
The sensor of the QHY268c is covered with an anti-reflective cover glass only. So for regular broadband imaging an UV/IR cut filter needs to be added. Here a 2” Astronomik L3 Luminance filter is screwed in the adapter. QHY has its own standard when it comes to spacers and adapters. A proprietary eco-system of spacers of different thickness, different screw connections, camera adapters etc is kept together through a ring of 6 screws. The benefit is that the connection is very strong with no wiggle. The flip side is that owning a QHY camera probably means some extra investment in the adapter system. On the above image the adapter set for Canon EF mount is mounted.
Sensor: 26 Megapixels
The sensor is APS-C sized and contains pixels with a very common size of 3.76 µm. In total this means that the camera produces 26 Megapixel images. Each file is about 52MB in size. The sensor can be read in one of four modes. Mode 0 is the most common one and referred to as the photographic mode. Mode 1 is high gain mode which gives more signal but at the cost of noise. Mode 2 is the extended full well mode which gives more dynamic range, but also at the cost of noise. Mode 3 is a modification of the extended full well mode, with a slight reduction of the noise.
Connectivity
The QHY268c is 12V DC powered. An special connection is at the back of the camera and a fitting special cable comes in the box. It allows the power cable to be screwed securely in its socket. Downloading the images to the computer is very fast (fraction of a second) and runs through a USB3 connection using the classical clunky USB-B connector. The filterwheel can also be connected to the camera, but QHY uses here a proprietary connector. This means that only a QHY filterwheel can be connected to this camera. When using a filterwheel from another brand, it needs to be connected to the computer. In contrast to the ZWO cameras, there is no USB hub on the camera.