QHYCCD QHY294M-Pro Mono

A 4/3-inch Sensor with 11.7 MP and 46.8 MP Modes

The core of the QHY294M-Pro is its adaptable Sony IMX492 back-illuminated sensor. In its default 11.7 MP mode, the sensor provides large 4.63µm pixels, ideal for collecting maximum light on deep-sky objects and pairing well with a wide range of telescope focal lengths. This mode also boasts a massive 65ke- full well capacity, preserving star color in dense fields and capturing subtle details in bright galactic cores.

When you need maximum resolution for smaller galaxies or lunar and solar imaging, you can switch to the extended 46.8 MP mode. This unlocks the sensor's native pixel array, providing the resolving power needed for highly detailed targets. This dual-mode capability allows the QHY294M-Pro to act as both a sensitive deep-sky camera and a high-resolution planetary imager, all in a single 650g body.

Dual Gain Architecture: 1.2e- Read Noise for Faint Targets

The QHY294M-Pro incorporates a dual gain system that automatically optimizes performance based on your gain setting. For bright objects or broadband imaging, the Low Gain Mode (LGC) prioritizes a high full well capacity. When the gain is set to 1600, the camera switches into High Gain Mode (HGC), dramatically dropping the read noise to a mere 1.2e- to 1.6e-.

This ultra-low read noise is a significant advantage for narrowband imaging, where signals can be extremely faint. By keeping electronics noise below the skyglow background, the HGC mode ensures that the faintest wisps of nebulosity in targets like the Cygnus Loop (NGC 6960) are captured with exceptional clarity and contrast.

-35°C Cooling & 256MB DDR3 Buffer for Clean, Stable Data

Consistent, repeatable data is critical for astrophotography, and the QHY294M-Pro is engineered for stability. The two-stage TEC cooler achieves a regulated temperature of -35°C below ambient, reducing thermal noise to a negligible 0.002e-/pixel/sec at -20°C. This aggressive cooling makes dark frames a near-perfect match to your light frames, resulting in cleaner final images.

• 256MB DDR3 Buffer: This onboard memory prevents dropped frames during high-speed captures and ensures reliable data transfer to your computer over the USB3.0 interface, even when saving large 46.8 MP files.
• Anti-Dew Heater: An integrated heater gently warms the optical window, preventing dew formation during humid nights and saving your imaging session from being cut short.
• Amp Glow Control: The camera's circuitry is designed to significantly reduce amplifier glow during long exposures, leading to more uniform calibration and a cleaner background in your stacked images.

QHY294M-Pro vs. ZWO ASI294MM Pro: A Tale of Two IMX492s

Both the QHY294M-Pro and its primary competitor, the ZWO ASI294MM Pro, are built around the same excellent Sony IMX492 sensor. As a result, their core imaging capabilities—resolution modes, pixel size, read noise, and full well capacity—are nearly identical. The choice between them often comes down to system integration and physical design.

• ZWO ASI294MM Pro Advantage: ZWO's camera has a significant ecosystem advantage for users of their ASIAIR wireless control system, offering seamless plug-and-play integration. Its red cylindrical body is also instantly recognizable and part of a vast ecosystem of accessories.
• QHY294M-Pro Advantage: The QHY294M-Pro features a robust, squared-off body design with a shorter back focus of 17.5mm, providing flexibility in complex imaging trains. QHY's drivers are known for their stability and broad compatibility with a wide range of third-party acquisition software beyond a single ecosystem.