ZWO ASI294MM Pro USB3.0 Cooled Mono Astronomy Camera - ASI294MM-P

ZWO ASI294MM Pro Monochrome Cooled Camera

Sony IMX492 Pregius Monochrome Sensor

The ZWO ASI294MM Pro is the monochrome version of one of ZWO's top selling cameras - the ASI294MC.  The Sony IMX294 is a CMOS image sensor with a monochrome square pixel array of approximately 47.08 M effective pixels. With high sensitivity, low dark current, no smear and excellent anti-blooming characteristics, the IMX492 has an electronic shutter function and is back illuminated.  The sensor itself is 19.1 mm x 13.0 mm in size, with a diagonal measurement of 23.1 mm.  

The Sony IMX294 has a pixel size of 4.64 um arranged in a 4144 x 2822 high resolution pixel array.  When running in Bin1-mode, the camera can operate at a resolution of 8288x5622 with a pixel size of 2.3 um!

The ASI294MM Pro has a very high QE value, with a peak at about 90%, but also has ultra-low readout noise of 1.2e.

This IMX294 has native 14-bit ADC for a dynamic range of 13 stops for beautiful sharpness and contrast as well as smoother, more natural color transitions.  

Back-Illumination

Sony’s back-illuminated CMOS image sensor improves the sensitivity and noise reduction – the key factors to enhancing image quality. It does this by radically realigning the fundamental pixel structure from front-illumination to back-illumination, while still retaining the advantages of CMOS image sensors such as low power consumption and high-speed operation.

With a conventional front-illumination structure, the metal wiring and transistors on the surface of the silicon substrate that form the sensor’s light-sensitive area (photo-diode), impede photon-gathering carried out by the on-chip lens. A back-illuminated structure minimizes the degradation of sensitivity to the optical angle response, while also increasing the amount of light that enters each pixel due to the lack of obstacles such as metal wiring and transistors. These components have been moved to the back-side of the silicon substrate.

USB3.0 & DDR3 Buffer

With features like USB 3.0 and 256MB DDR3 buffer, the ASI294MM Pro provides stable and secure data transmission that can effectively avoid frame-dropping issues during long exposures and reduces the glow effect caused by slow reading speed.

Large well depth capacity, low read-out noise & high dynamic range

The full well capacity of 66387e of ASI294MM Pro is near the top of all ASI DSO cameras. It ensures a very high dynamic range of up to 13 stops that will greatly reduce the issue of overexposed images and also help to collect richer color information.

When the gain value is set to 120, the HCG high gain mode is turned on. We’re not saying it’s magic…but we’d like to think it is pretty close. With the HCG-mode turned on, the readout noise is greatly reduced, and the dynamic range is basically unchanged.

Unlocked Bin1 Mode

Yet another perk of the ASI294MM Pro is that the pixel size is switchable – you can switch between unlocked Bin1 mode and Bin2 mode anytime in your astrophotography software. The unlocked Bin1 mode changes the pixel size into 2.3um and increases resolution to 8288×5644. The ability to unlock bin1-mode was a popular request from ZWO customers. 

Remember that using Bin1-mode will decrease the full well capacity compared to the standard bin2-mode.

Unlocked Bin1: 12bit ADC, 2.3um pixel size, 47 megapixels, 8288*5644 resolution, 14k full well capacity.

Bin2: 14bit ADC, 4.6um pixel size, 11.7 megapixels, 4144*2822 resolution, 66k full well capacity.

Cooling & Dew

Thanks to two-stage TEC cooling, the ASI294MM-P can lower the CMOS sensor temperature to more than 35 degrees Celsius below ambient temperature, which can greatly reduce dark current generation and sensor noise even during extended exposure times.

*The Delta T 35℃ is tested at 30℃ ambient temperature. It might get down when the cooling system is working for a long time. Also, as the ambient temperature falls, the Delta T would decrease.

The unique dark current suppression technology can further reduce dark current noise. When it’s cooled to -20℃, the current noise can be as low as 0.0022e/s/pix, which is completely negligible!

Please Note: External power supplies are needed for all ASI cooled cameras.  ZWO recommends you use a 12V@3A DC Adapter with a 5.5*2.1mm center pole positive or a lithium battery with 11-15V to power the camera.  Do not use a power supply that goes out of this recommended voltage range or irreparable damage to the camera may occur.