QHY268M PRO I [MONOCHROME]

 

The QHY268M Pro I is a high-performance CMOS camera specifically designed for advanced scientific, observational, and astrophotography applications. Equipped with the APS-C-format Sony IMX571 BSI CMOS sensor, it offers 26 Megapixels, back-illuminated architecture, and a native 16-bit ADC that ensures smooth gradations and high fidelity in deep-sky captures.

 

The built-in 10Gbps fiber interface can can work in combination with the QHYCCD PCIE2.0x8 data grabber card. Compared to the USB3.0 interface, you can boost the data transfer from 5Gbps to 10Gbps for each 10Gigabit port, with 800MByte/s effective data rate. When both Gigabit ports are used together, the speed jumps to 1.6GBytes/s. 

Unlike USB 3.0 found on many cameras, fibre offers far greater range and speeds while being impervious to electromagnetic interference. For example, the maximum range of active (powered) USB 3 cables is up to 15 metres. Without an active connection, this reduces to 2-3 metres. By contrast, fibre can extend up to 300 metres without any reduction in speed or reliability. An optional long-distance optical module is also available, extending the length up to 40km.

 

 

A 6 pin GPIO socket is available on the back of the camera, allowing the camera to be reprogrammed to different capture modes. It is also possible to reprogram the FPGA for more complex timing.

 

Optimized Design and Reduced Backfocus

The QHY268M Pro I features a new front design that reduces the backfocus distance to 14.5 mm, compared to 17.5 mm with the previous design. This update improves compatibility with compact filter wheels, correctors, and reducers, especially those requiring a total focusing distance of 55–56 mm. The camera includes all the necessary adapters to achieve this distance without complications.

 

Advanced Capture Modes
The QHY268M Pro I offers three basic selectable readout modes and three 2CMS modes, allowing you to adjust the camera's performance based on the type of object or capture technique used:

• Mode #0 – Photographic Mode: Ideal for general astrophotography. Readout noise drops rapidly as the gain value increases; It reaches 3.88e- at gain 26. At this point, the full-well capability is reduced to 34977e-, which is suitable for long exposures. In fast telescopes (f/2.2 to f/4), gain 0 can be used to take advantage of the maximum Full Well capability of 100000e-.
• Mode #1 – High Gain Mode: Designed for narrowband capture, where long exposures are required. In this mode, readout noise remains very low (~3e-) in the gain range between 0 and 55. At gain 56 this mode generates the smallest readout noise for this camera, with only 1.69e-. A Full Well capacity of 28528e- makes this mode perfect when your subject is particularly dark and you need to push your gain.
  

• Mode #2 – Extended Full Well: Optimal for objects with bright stars or high-contrast scenes. This mode provides maximum full-well capability throughout the entire gain range, allowing details to be captured without excessive saturation.
  

• Mode #3 to #5 – 2CMS (Correlated Multiple Sampling): Uses correlated multiple sampling to further reduce effective readout noise. When combined with Extended Full Well mode, it significantly improves dynamic range, especially useful in scenes with high brightness variability.
  

 

Unaltered RAW Quality and an Optimized Sensor

Unlike conventional DSLR cameras, the QHY268M Pro I delivers true RAW output, capturing only the original sensor signal without applying noise reduction, hot pixel removal, or other internal algorithms that degrade image quality. This gives astrophotographers complete control during processing, maintaining data integrity and maximizing final performance in scientific or deep-sky astrophotography.

 

Advanced Thermal Control

The QHY268M Pro I incorporates a dual-stage thermoelectric cooling (TEC) system, capable of reducing the sensor temperature to -35°C below ambient, ensuring quiet performance even in hot climates. Dark current remains extremely low, at just 0.0005 electrons/pixel/second at -20°C.

Additionally, QHYCCD applies proprietary thermal noise control technology, designed to minimize CMOS sensor noise without affecting the purity of the RAW file. This unique system is more effective than conventional noise reduction methods found in other astronomical cameras on the market.

The liquid cooling versions in combination with the optional liquid cooler kit (sold separately) bring this down by approximately 10°C further. Additionally, thanks to the lack of moving mechanical parts, the liquid-cooled versions will never introduce any vibration, keeping the images free from jitter.   

Dew and Condensation Protection
To prevent the formation of condensation or ice crystals, the QHY268M Pro I uses a comprehensive dew protection system, which protects both the CMOS sensor glass and the front optical window with integrated heating. This ensures clear images free from thermal interference even on nights with high relative humidity.

High-Performance Buffer Memory
The camera is equipped with a 2GB DDR3 memory buffer, which facilitates efficient image transfer to the computer, especially when there is high traffic on the USB port, the system is running multiple tasks, or disk write speeds are limited. This feature ensures stable, lossless capture, even during extended or automated capture sessions.

Advanced Optical Coating and Precision Sensor Alignment
To eliminate halos around bright stars, the QHY268M Pro I employs a double-sided AR (anti-reflection) coated optical window, instead of the common UV/IR coating. The sensor is also protected by AR-coated glass, maximizing light transmission and minimizing unwanted internal reflections.

Each unit is individually calibrated with a high-precision measurement system, ensuring orthogonal sensor placement with an accuracy of better than ±20 µm relative to the image plane. This eliminates the need to adjust the sensor tilt, a significant advantage especially in fast telescopes (f/2.8 – f/4), where tilt tolerances are critical.

Complete Absence of Amplifier Glow
Thanks to the optimized electronic design, the QHY268M Pro I exhibits zero amplifier glow, even during extremely long exposures. This allows for cleaner calibrations, improved signal-to-noise ratios, and artifact-free capture.

Mechanical drawing

Specifications

 

Sensor	Sony IMX571 back-illuminated APS-C CMOS
Resolution	26 Megapixels
Effective Pixel Area	6252 x 4176
Total Pixel Area	6280 x 4210 (include optical black area and overscan area)
Pixel size	3.76 µm
Sensor size	23.61 mm x 15.83 mm (28.43 mm diagonal)
Quantum efficiency	91%
Exposure range	30 µs - 3600 s
Read noise	1.1e- to 3.5e- Standard Mode - 5.3e- to 7.4e- Extended Full Well Mode
Dark current	0.0005e-/pixel/sec @ -20C - 0.001e-/pixel/sec @-10℃
Full well capacity	51ke- in Standard Mode  (>80ke- in Extended Full Well Mode
Bit rate	Native 16 bit ADC
Frame rate	USB: 6.5 fps at full resolution (16 bits), 10Gb fibre: 6.7 fps at full resolution (16 bits)
Shutter type	Electronic rolling shutter
Cooling	ΔT of 35°C Dual Stage TEC cooler - ΔT of 45°C LQ
Memory buffer	2 GB DDR3
ROI	Supported
Optical window	AR+AR High Quality Multi-Layer Anti-Reflection Coating
Ports	USB 3.0, Dual 10GbE (10 Gigabit Ethernet), Filter Wheel Control
Back focus	14.5 mm
Connections	M54 x 0.75 female thread
Dimensions	Ø 90 mm; ↨ 97–98 mm
Weight	1020 g

 

Full Frame Rates

USB3.0	6.7 FPS @ 8bit - 6.5 FPS @ 16bit
12bit High Speed Mode	14.5 FPS @ 8bit - 6.5 FPS @ 16bit
PCIE Mode	6.7 FPS @ 8bit - 6.7FPS@16bit

 

Full Frame Rates

2048lines (USB3.0)	13.6 FPS @ 8bit - 12.7 FPS @ 16bit
1080lines (USB3.0)	25.4 FPS @ 8bit - 21.8 FPS @ 16bit
768lines (USB3.0)	35.5 FPS @ 8bit - 28.3 FPS @ 16bit
480lines (USB3.0)	52.9 FPS @ 8bit - 39.6 FPS @ 16bit

 

2048lines (12bit High Speed Mode)	29.1 FPS @ 8bit - 12.7 FPS @ 16bit
1080lines (12bit High Speed Mode)	52.5 FPS @ 8bit - 21.8 FPS @ 16bit
768lines (12bit High Speed Mode)	73.2 FPS @ 8bit - 28.3 FPS @ 16bit
480lines (12bit High Speed Mode)	110 FPS @ 8bit - 39.6 FPS @ 16bit

2048lines (PCIE Mode)	14.0 FPS @ 8bit - 14.0 FPS @ 16bit
1080lines (PCIE Mode)	25.4 FPS @ 8bit - 25.4 FPS @ 16bit
768lines (PCIE Mode)	35.5 FPS @ 8bit - 34.6 FPS @ 16bit
480lines (PCIE Mode)	52.9 FPS @ 8bit - 52.9 FPS @ 16bit

 

Included items

• QHY268M-PRO I
• USB 3.0 cable (1.5 m)
  
• Power cable (5.5–2.1 mm male jack with locking nut to 5.5–2.1 mm female jack)
• Power supply 240 V to 12 V 5A with 5.5–2.1 mm power jack
  
• M54 x 0.75 to 2" adapter (2.5 mm optical thickness, M48 x 0.75 internal thread for standard 2" filters)

 

 

 

 

Guide to installing QHY and ASCOM drivers for QHYCCD cameras.

 

Downloads

QHY camera drivers

QHY 268M Pro I manual

QHY 268M Pro I Science observation