QHYCCD QHY294M Pro Mono Cooled Astronomy Camera
The QHY294M Pro is a high-performance, cooled monochrome CMOS camera designed for deep sky astrophotography and scientific imaging. Featuring the back-illuminated Sony IMX492 sensor with selectable 11.7MP (12-bit) or 47MP (14-bit) output modes, it provides exceptional flexibility for both high-resolution imaging and high-sensitivity binning workflows.
Its deep cooling system, exceptionally low read noise, high quantum efficiency, and support for 2x2 binning modes make the QHY294M Pro ideal for capturing faint nebulae, galaxies, star clusters, and narrowband data.
Main Features
- Sony IMX492 BSI Monochrome Sensor for high sensitivity and low noise
-
Switchable Resolution Modes:
- 11.7MP high sensitivity (native) mode
- 47MP high resolution mode
- Extremely low read noise for clean data and faint target capture
- Dual-stage TEC cooling up to -35°C below ambient
- 1GB DDR3 buffer ensures stable data transfer
- No amplifier glow for clean calibration frames
- Narrowband imaging ready – superb with 36mm and 2" filters
Technical Specifications
| Sensor | Sony IMX492 BSI CMOS (Mono) |
| Pixel Size | 4.63µm |
| Resolution | 11.7MP (4144 × 2822) or 47MP (8288 × 5644) |
| ADC | 14-bit / 12-bit modes |
| Full Well Capacity | ~66ke- (extended dynamic range) |
| Read Noise | Down to ~1.2e- |
| Cooling | Dual-stage TEC, up to -35°C |
| Interface | USB 3.0 SuperSpeed |
| Back Focus | ~ 17.5mm (with adapters) |
The294Pro has 11.7 MP at 4.63um, 14-bits A/D. IMX492 chips have 46.8 million 2.315um pixels, which Sony 2×2 bins on-chip to create the sensor’s advertised 11.7 million 4.63um pixel array.
The QHY294 Pro CMOS sensor has a dual gain mode, HGC (high gain) and LGC (Low gain). The QHY294 Pro will switch the two modes automatically when the gain is set to 1600 you will get the benefits of the ultra low read noise (1e- to 1.6e-) of the HGC mode and a full well capacity of about 14.5ke- at the switch point setting.
BSI
One benefit of the back-illuminated CMOS structure is improved full well capacity. In a typical front-illuminated sensor, photons from the target entering the photosensitive layer of the sensor must first pass through the metal wiring that is embedded just above the photosensitive layer. The wiring structure reflects some of the photons and reduces the efficiency of the sensor.
In the back- illuminated sensor the light is allowed to enter the photosensitive surface from the reverse side. In this case the sensor’s embedded wiring structure is below the photosensitive layer. As a result, more incoming photons strike the photosensitive layer and more electrons are generated and captured in the pixel well. This ratio of photon to electron production is called quantum efficiency. The higher the quantum efficiency the more efficient the sensor is at converting photons to electrons and hence the more sensitive the sensor is to capturing an image of something dim.
TRUE RAW Data
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. This can have a negative effect on the image for astronomy such as the “star eater” effect. However, QHY Cameras offer 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 and other scientific imaging applications.
Anti-Dew Technology
Based on almost 20-year cooled camera design experience, The QHY cooled camera has implemented the fully dew control solutions. The optic window has built-in dew heater and the chamber is protected from internal humidity condensation. An electric heating board for the chamber window can 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.
Cooling
In addition to dual stage TE cooling, QHYCCD implements proprietary technology in hardware to control the dark current noise.
| Model | QHY294M Pro |
| CMOS Sensor | SONY IMX492 |
| Mono/Color | Mono Only |
| FSI/BSI | BSI |
| Pixel Size | 4.63μm*4.63μm |
| Effective Pixel Area | 4164*2796 |
| Total Pixel Area | – |
| Effective Pixels | 11.7 MP 46.8 MP（Extended Pixel Mode） |
| Sensor Size | 4/3 inch (19.28mm*12.95mm) |
| A/D | 14-bit A/D |
| Full Well Capacity (1×1, 2×2, 3×3) | 65ke- |
| Frame Rates | Standard 11.6mega pixel mode Full resolution: 16.5FPS@14bit ROI: 2160lines 21FPS 1080lines 41FPS 960lines 46FPS 768lines 56FPS 480lines 87FPS 240lines 156FPS 100lines 290FPS47mega pixel mode 8340*5644 4FPS@14bit and 8bit |
| Readout Noise | 1.6- to 1.2e- (High Gain Mode) 6.9- to 5.2e- (Low Gain Mode) |
| Dark Current | 0.002e-/pixel/sec @-20℃ 0.005e-/pixel/sec @-10℃ |
| Exposure Time Range | 60μs-3600sec |
| Recommend Gain* | 1600 (11MP Mode) 2600 (47MP Mode) |
| Amp Control | Amplifer Glow Can be reduced during long exposure |
| Shutter Type | Electronic Rolling Shutter |
| Computer Interface | USB3.0 |
| Built-in Image Buffer | 256MB DDR3 Memory Buffer |
| Cooling System | Dual Stage TEC cooler（about -35℃ below ambient, test temperature +20℃） |
| Optic Window Type | AR+AR High Quality Multi-Layer Anti-Reflection Coating |
| Telescope Interface | M42/0.75 |
| Back Focal Length *Learm more: https://www.qhyccd.com/adapters/ |
17.5mm（±0.2） |
| Anti-Dew Heater | Available |
| Humidity Sensor | – |
| Firmware/FPGA remote Upgrade | – |
| Weight | 650g |
Recommended For
- Deep Sky Astrophotography (DSOs)
- Narrowband and LRGB imaging
- Remote / automated observatories
- Scientific imaging and photometry
Filter wheel and filters not included.
Monoceros Zone Mosaic By @toni_fabiani
Lens: Samyang 135mm F2.0 ED UMC
Camera: QHY294M Pro
SII: 40×600″
OIII: 30×600”
For cameras with a sensor larger than 1-inch and smaller than APS-C (QHY163m/294m) we recommend a combination of CFW3M (US) + OAGM (optional);
| Model | BFL Consumed | Filters Supported |
| QHY163M/294M | 17.5mm | 7 position
36mm unmounted |
| CFW3M-US | 17.5mm | |
| OAGM | 10mm |
Back Focal Length (BFL), in the commercial camera field, refers to the design distance from the center of the rear lens element to the surface of the sensor. Generally, the lens will only focus correctly at infinity if the camera’s back focal length meets the standard requirements provided by the lens manufacturer. This is also true for many Multi-Purpose Coma Correctors designed to be used on telescopes before the camera.
| Optical system | Back focal length required |
| Typical Multi-Purpose Coma Corrector | 55mm – 57.5mm |
| Canon 35mm lens | 44.1mm |
| Nikon 35mm lens | 46.5mm |
Note:
- If you only own CFW3M-SR whose BFL is 20.5mm rather than 17.5mm, this adapter combination can still be used, just remove the 3mm and 0.5mm adapters.
- If your MPCC requires a BFL different from 55mm, this adjustment can be made by selecting the appropriate spacer between the MPCC and the OAG. For example, an MPCC that requires 57.5mm can be used instead by adding a spacer ring or rings that add 2.5mm of BFL. to the diagram above.
- If you don’t use an OAG, you can use a 10mm spacer adapter in the adapter kits to replace the original position of OAG.
- Put OAG at the position next to the M48 Output to make both main cam and guiding cam focused.
Note: You need to remove the filter wheel and the original connection interface of the camera and replace it with a new adapter.
In the Box
- QHY294M Pro Camera
- 12V Power Cable
- USB 3.0 Data Cable
- M42/M54 Adapters (depending on revision)
- Desiccant Tube
- Documentation & Quick Start Guide