The QHY247C uses an APC-S format, 24 Megapixel, 14bit CMOS color sensor, the Sony IMX193. This sensor is also used in the Nikon D5300 and D5500 cameras. It has 2.7e- read noise at lowest gain, 2.2e- read noise at unity gain (system gain = 1e/ADU), and 1.0e- at high gain. The QHY247C camera has the LOWEST read noise and thermal noise in the 165/168/247/367 production line.
True RAW Image Output
While the QHY247C has the same CMOS sensor as the D5300 and D5500 cameras, unlike the consumer cameras, the QHY247C offers True RAW Image output. In the DSLR implementation there is a RAW image output, but typically it is not completely RAW. Some evidence of noise reduction and hot pixel removal is still visible on close inspection. However, the QHY247C offers TRUE RAW IMAGE OUTPUT and produces an image comprised of the original signal only, thereby maintaining the maximum flexibility for post-acquisition astronomical image processing programs.
Unique Thermal Noise Reduction Technology
In addition to efficient 2-stage thermoelectric cooling, QHYCCD employs a unique thermal noise control technology to reduce CMOS sensor noise to a very low value without affecting the integrity of the raw image. This proprietary technology can be found to improve noise performance across the whole 165/168/247/367 product line, producing much better noise reduction than any competing camera model.
Zero Amplifier Glow
The QHY247C has zero amplifier glow no matter how long the exposure time.
Advanced AR Coating on CMOS sensor
The IMX193 sensor has AR coatings on the CMOS sensor glass. It also has AR coating on the micro-lens array. This design greatly reduces the halo around bright stars.
128MB DDRII Image Buffer
QHY247C has 128MB DDRII image buffer to cache the image and avoid the risk of a frame loss. The image data is stored in the DDR immediately after acquisition and then transferred to computer from the memory buffer. This avoids problems of a busy USB port when there are other peripherals using the same port as the camera.
QHYCCD has more than 10 years of experience designing cooled cameras. The QHY247C receives the benefit of that decade of design work by featuring full anti-dew technology for both CCD sensor cover glass and the sensor chamber optical window. The QHY247C has an electric heating board for the chamber window to prevent the formation of dew and the sensor itself is kept dry with our silicon gel tube socket design for control of humidity within the sensor chamber.
AR+AR Optical Window
In order to avoid halos around bright stars the QHY247C has a AR+AR coated optical window rather than the common IR cut window for Single-Shot Color cameras. This permits full access to the red wavelength of H-alpha and SII without attenuation by the window coating. For RGB color balance, without passing the near IR wavelengths above 700nm, a separate removable 2-inch UV/IR filter with the desirable bandpass characteristics is placed in a custom filter holder in front of the camera.
* Each camera is carefully calibrated at the factory with a high-precision axis measurement device. Orthogonal placement of the sensor is guaranteed to be flat to the image plane to better than +/-20um across the sensor from edge to edge, so there is no need to adjust for camera tilt absent mechanical errors elsewhere in the image train.