QHYCCD QHY268M Mono

Sony IMX571 Sensor: 26 Megapixels and Native 16-bit A/D

At the core of the QHY268M is Sony's APS-C format IMX571 sensor, offering a 6252 x 4176 pixel array. Unlike cameras that use 12-bit or 14-bit converters, the QHY268M employs a true, native 16-bit analog-to-digital converter directly on the sensor chip. This allows it to sample the entire full well depth with 65,536 distinct levels, giving smooth tonal gradations in bright areas.

The sensor's back-illuminated (BSI) structure places the wiring layer behind the photosensitive area, maximizing the light-gathering ability of each 3.76μm pixel. This design boosts quantum efficiency and sensitivity, allowing you to capture fainter signals in shorter exposure times. Furthermore, the QHY268M outputs a true raw data stream, free from the in-camera noise reduction or "star eater" algorithms found in some DSLRs, ensuring maximum data integrity for post-processing.

Dual Readout Modes: 1.1e- Noise vs. 80ke- Full Well

The QHY268M features multiple user-selectable readout modes, allowing you to tailor the camera's performance to your specific target. For most deep-sky objects, Photographic DSO Mode delivers a deep 51ke- full well capacity and read noise as low as 1.1e-, suited to faint, low-contrast nebulosity.

For targets with extreme dynamic range, such as the Horsehead Nebula (Barnard 33) region with the brilliant star Alnitak, Extended Full Well Mode boosts the pixel capacity to an impressive 80ke-. This prevents bright stars from saturating while you expose for the delicate surrounding nebulosity, preserving color and detail across the entire scene. The QHY268M also has zero amplifier glow, so long exposures do not show corner glow from the readout electronics.

Stable -35°C Cooling & 0.0005e-/pixel/sec Dark Current

To suppress thermal noise during long exposures, a robust dual-stage thermoelectric cooler reduces the sensor temperature to a stable -35°C below the ambient environment. This cooling gives a low dark current of just 0.0005 e-/pixel/sec when the sensor is held at -20°C, ensuring that your images are dominated by photon signal, not thermal noise. A clean, low-noise signal is critical for bringing out faint structures in galaxies and nebulae during processing.

• Anti-Dew Heater: An integrated heater on the optical window prevents dew or frost formation during humid nights, ensuring a clear light path to the sensor.
• Humidity Sensor: The QHY268M has an integrated humidity sensor for the sensor chamber, so you can check its condition and dry it with the included desiccant tube if moisture appears.

1GB DDR3 Buffer: 6.0 FPS at 16-bit Over USB 3.0

To manage the large data stream from the 26 Megapixel sensor without overwhelming your computer's CPU, the QHY268M incorporates a 1GB DDR3 memory buffer. This buffer ensures reliable, drop-free image transfer over the USB 3.0 interface, even when running at the maximum full-resolution 16-bit frame rate of 6.0 FPS. A large buffer is essential for smooth operation, preventing dropped frames or stuttering during a sequence and making the imaging experience more stable, especially in remote observatory setups.

The QHY268M is primarily a deep-sky camera, but region-of-interest (ROI) selection raises the frame rate. By reducing the readout area to 480 lines, the camera reaches up to 50 FPS in 8-bit mode, which helps with focusing and short, fast captures of bright targets.

Flexible 14.5mm Back Focus with M54 Interface

The QHY268M is designed with a short 14.5mm (±0.2mm) back focal distance, measured from the M54 female threads on the front of the camera. This leaves room within the common 55mm back focus for a filter wheel and off-axis guider. The included Adapter Kit B1 provides the necessary spacers and adapters to achieve a 55mm back focus with either M48 or M54 threads, for correctors that need that spacing.