Astronomy Specialist



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The QHY 294C Pro is a popular cooled colour camera with large pixels and low noise. It contains the Sony IMX 294 Exmor R with exceptional low light capabilities. The pixels measure 4.63µm, making this camera ideal for medium-long focal length telescopes but also camera lenses and short refractors that may suffer from elongated stars on the borders. Large pixels can mask minor aberrations of the telescope that are generally visible in cameras with small pixels (2-3 µm).

QHY 294C Pro colour cooled CMOS deep sky astronomy camera

The QHY294C Pro camera is capable unlocking the on-chip binning to provide two readout modes. The first mode reads the sensor in "locked" mode with the original resolution of 11.6Mp, 4.63µm pixel and an bitrate of 14 bits. The second read mode unlocks the binning to produce a resolution of 46.8Mp with 2.315µm pixel and bitrate of 12 bits. 

This camera has a two-stage TEC cooling system that brings the temperature of the sensor 30°C/35C° below ambient for low noise imaging, even in warm climates. The dark current at -20°C is only 0.002 electron/pixels. In addition to 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. The QHYCCD proprietary technology produces a much better noise reduction than any other astronomy camera in the market. QHYCCD has more than 10 years of experience designing cooled cameras. The QHY 294C Pro employs a full anti-dew technology for both CCD sensor cover glass and the sensor chamber optical window.

The 256MB DDR III memory buffer facilitates the download of images to the computer, especially when USB traffic is high, the writing speed of your computer is slow or occupied in other processes. 

In order to avoid halos around bright stars, the QHY 294C Pro has an AR coated optical window on both sides rather than the common IR/UV cut window. Also, the protection glass of the sensor is AR coated to maximize light transmission and minimize internal reflections. For a better RGB colour balance, it is recommended to use a UV/IR cut filter. The QHY 294C Pro has zero amplifier glow no matter how long the exposure is.

The camera 2 capturing modes:

  • LGM (Low Gain Mode) #0
  • HCG (High Gain Mode) #1

The system will switch between the two modes automatically when the gain is set to 1600.



Sensor Sony IMX294 CMOS - COLOUR
Resolution 11.6 Megapixels 4164 X 2796 / 46.8 Megapixels 8328 X 4992 in unlocked mode
Pixel size 4.63 µm (2.315µm in unlock mode)
Sensor size 19.28 mm x 12.95 mm (23.23 mm diagonal)
Exposure range 60µs-3600s
Read noise 1.6e-/1.2e- at HGC mode ; 6.9e-/5.2e- at LGC mode
Dark current 0.002e-/pixel/sec @ -20C
Full well capacity 65,000 e- 
Bit rate 14 bit ADC (12 bit in unlocked mode)
Frame rate 16.5 fps at full resolution (16 bits)
Shutter type Rolling shutter
Cooling ΔT of 30°C/35°C Dual Stage TEC cooler
Memory buffer 256 MByte DDR3
ROI Supported
Compatibility Mac, Windows, Linux
Optical window AR coated (both sides)
AR coating on sensor YES
Ports USB 3.0
Compatibility Mac, Windows, Linux
Back focus 17mm ±0.3mm
Connections M42 x 0.75 female thread (embedded in camera dovetail)
Dimensions Ø 90 mm; ↨ 103.20 mm
Weight 650 gr
Power supply 12V 3A  (2.1×5.5 mm connector)



  • QHY 294C Pro
  • USB 3.0 cable (1.5m)
  • Screw jack power cable (5.5-2.1mm male jack with locking nut to 5.5-2.1mm female jack)
  • Lighter plug adapter to 5.5-2.1mm power jack
  • Desiccant Drying Tube (desiccant not included)
  • M54 x 0.75 to 2"adapter (2.5mm optical thickness, M48 x 0.75 internal thread for standard 2" filters)






      Video presentation of the QHY294C.


      Guide to installing QHY and ASCOM drivers for QHYCCD cameras.

      ZWO camera software QHY camera drivers

      ZWO camera software QHY 294C Pro manual

      Welcome Newcomer