ZWO ASI 294MM USB 3.0 Mono Camera
 ZWO ASI 294MM USB 3.0 Mono CameraZWO ASI 294MM USB 3.0 Mono Camera 

ZWO ASI 294MM USB 3.0 Mono Camera

Now: £947.00 (Save:  £105.00) Was:  £1,052.00✓ 2 year warranty


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About this product

Model:  zwo_asi294mm
Part Number:  ASI294MM

New Mono Version of the ASI294MC Camera!

The ZWO ASI294MM features a high resolution (4144x2822) back-illuminated, 4/3” format, 14-bit ADC sensor with 4.63um pixels.  

It also has an impressive 66ke- full well capacity, very high QE (peak around 90%) and an ultra-low readout noise of 1.2e.

Default 'Bin2' mode combines pixels in a 2x2 group for a 4.6um pixel size, with 14bit ADC, 11.7 megapixels (4144x2822) resolution and 66k full well capacity.

'Unlocked Bin1' mode enables you to use the camera at its native pixel size of 2.3um with 12bit ADC at 47 megapixels (8288x5644) resolution and 14k full well capacity.

The two modes make this a versatile camera suitable for use with a range of imaging setups and targets.

All ZWO cameras include a 2-year warranty. 


  • Sony IMX492 CMOS Sensor
  • Extremely low read noise - 1.26e @30db gain
  • 14Bit ADC - provides real 14bit dynamic range
  • Electronic shutter - no issues with vibrations sometimes found in mechanical shutters
  • USB3.0 Port (back compatible with USB2.0)
  • AR-coated protective window - all light can pass
  • Compatible with Windows / Mac OS / Linux

14-bit ADC and 13stops dynamic range

The Mono ASI294MM has very similar parameters as the colour ASI294MC model. Both have 14bit ADC and high dynamic range of 13 stops (even higher than the ASI1600MM Pro camera). 


Camera Field of View Simulator

Backlit Sensor

The back-illuminated CMOS sensor improves sensitivity and noise reduction - key factors that enhance image quality - while retaining the low power consumption and high-speed characteristics of CMOS image sensors. 

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 minimises the degradation of sensitivity to 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 that have been moved to the reverse of the silicon substrate.

Unlocked Bin1 Mode

The ASI294MM offers switchable pixel size. The default setting is 'Bin2' which gives 4.6um pixels but you can switch to 'Unlocked Bin1' mode to use the native 2.3um pixel size. 

Bin2 (The default mode): 14bit ADC, 4.6um pixel size, 11.7 megapixels (4144x2822) resolution and 66k full well capacity.

Unlocked Bin1: 12bit ADC, 2.3um pixel size, 47 megapixels (8288x5644) resolution and 14k full well capacity.

You can learn the more differences between unlocked Bin1 and Bin2 modes by comparing the performance charts below.

Camera Performance

The ASI294MM main features are large well depth capacity, low read-out noise and high dynamic range.

The cameras full well capacity (66387e) is near the top of all ASI DSO cameras so provides very high dynamic range (up to 13stops) and rich colour gradation.

When the gain value is 120, the magical HCG high gain mode is turned on. This reduces readout noise (as low as 1.2e) with minimal affect on dynamic range. 

Performance in Bin1 mode shown below:

If the sampling accuracy achieved with the 2.3um pixel size falls into a reasonable range, then the unlocked Bin1 mode will enhance object detail. However, you will lose dynamic range and the bit depth of ADC. Also the image files in Bin1 mode will probably be 4 times bigger than Bin2. So unlocked Bin1 mode is a double-edged sword that is available for use as you wish. 

Reliable Mechanics

ZWO's tried and trusted design has been extensively tested and very stable. Four screws on the camera seal the sensor chamber so the camera can be used in higher humidity environments without dew problems. 

QE Value

As ZWO’s latest BSI (BackSide Illuminated) mono camera, the ASI294MM has very high QE performance (peak value is around 90%). This is higher than the colour version, and higher even than the ASI1600MM.

ASI294MM vs ASI1600MM 


USB3.0 & 256M DDR3 Memory

The ASI294MM is equipped with a USB 3.0 transmission interface and an integral 256MB DDR3 cache to ensure stable and secure data transmission. Under long exposure, it effectively avoids frame dropping and greatly reduces glow effect caused by slow reading speed.

For information on amp glow please refer to this tutorial: “What is Amp-glow and how do I manage it?“

Mechanical Diagram


What's in the box

  • ASI294MM-Pro Camera
  • T2-1.25" Nosepiece Adapter
  • 1.25" Cap
  • 2.0" Cap
  • 2-metre USB 3.0 Cable
  • T2-1.25" Adapter
  • Quick Start Guide
  • Driver CD
  • ST-4 Cable


Sensor 4/3″ SONY IMX492 CMOS
Diagonal 23.2mm
Resolution 11.7Mega Pixels 4144X2822
Pixel Size 4.63µm
Shutter Rolling shutter
Exposure Range 32µs-2000s
ROI Supported
Read Noise 1.2e @39db gain
QE peak TBD
Full well 66ke
ADC 14bit
DDRIII Buffer 256MB
Interface USB3.0/USB2.0
Adaptor M42X0.75
Protect window AR window
Dimensions 78mm Diameter
Weight 410g
Back Focus Distance 6.5mm
Cooling Regulated Two Stage TEC
Delta T 35°C below ambient
Camera Power consumption 650mA at 5V
Cooler Power consumption 12V at 3A Max
Working Temperature -5°C—45°C
Storage Temperature -20°C—60°C
Working Relative Humidity 20%—80%
Storage Relative Humidity 20%—95%


Downloads / Manuals

The following manuals and downloads are available for this product:


ZWO Software and Drivers


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