ZWO ASI 294MM Pro Cooled Mono Astrophotography Camera is a micro four-thirds camera packed with features that help you produce world-class images. It is the monochrome version of ASI294MC Pro.
The ASI 294MM Pro features a 14-bit ADC with 4.63 um pixels, and 13 stops dynamic range. It has an impressive 66ke- full well capacity and a big 4144*2822 resolution. A very high QE value with a peak at around 90% and an ultra-low readout noise of 1.2e. If you are looking for a small-format monochrome camera for astrophotography, then the ASI294MM Pro will be your ideal choice.
Compare: This ASI294MM Pro has very similar parameters as its color version. Both have the 14-bit ADC and a high dynamic range of 13 stops, which is even higher than that of ASI1600MM Pro camera.
The back-illuminated CMOS sensor improves sensitivity and noise reduction; the key factors to enhancing image quality, while radically realigning their fundamental pixel structure from front-illumination to back-illumination. It has retained the advantages of CMOS image sensors such as low power consumption and high-speed operation.
This back-illuminated structure minimizes 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. (Unlike with a conventional front-illumination structure, where the metal wiring and transistors on the surface of the silicon substrate that form the sensor’s light-sensitive area (photo-diode) and impede photon gathering carried out by the on-chip lens.)
Large well depth capacity, low read-out noise and 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 up to 13 stops that will greatly reduce overexposure probability and help gain richer color gradation.
When the gain value is 120, the magical HCG high gain mode is turned on, the readout noise will be largely decreased (as low as 1.2e), and the dynamic range is basically unchanged.
There are four screws on the camera that seal the sensor chamber. This kind of design has been extensively tested and is very stable. Even when used in higher humidity environments, this camera will still work fine without dew problems.
Unlocked Bin1 Mode
Yet another perk of the ASI294MM Pro is that the pixel size is switchable – the default setting is Bin2, but you can switch to Bin1 anytime in your astrophotography software. This changes the pixel size to 2.3um and increases resolution to 8288×5644. This is what we called “Unlocked Bin1 Mode”. The ability to unlock bin1-mode was a popular request from our customers. Of course, we listened to you and worked quickly to make it possible.
Remember that using Bin1mode 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 (The default mode): 14bit ADC, 4.6um pixel size, 11.7 megapixels, 4144*2822 resolution, 66k full well capacity.
You can learn more differences between unlocked Bin1 and Bin2 modes by comparing the performance charts.
If the sampling accuracy you get with the 2.3um pixel size falls within a reasonable range, then the unlocked Bin1 mode will help you get more object details. However, you will lose dynamic range and ADC bit depth. Also, the image files you get at Bin1 will probably be around 4 times bigger than Bin2.
So in the end the unlocked Bin1 mode is double-edged, you may choose to use it or not depending on the specific circumstances during your imaging sessions.
The ASI294MM Pro has a very high QE performance, not only higher than its color version but even over the ASI1600MM Pro. It is estimated that the QE peak value is about 90%.
ASI294MM Pro vs ASI1600MM Pro
Cooling: Two-Stage TEC for Ultra-Low Dark Current
This camera uses two-stage TEC cooling that can lower the CMOS sensor temperature to between about 35c and 40c degrees below ambient temperature. This can greatly reduce dark current generation and sensor noise, even with extended exposure times.
The unique dark current suppression technology can even 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!
See the Read Noise and other graphs in the Gallery tab.Click on the thumbnails to view and hold CTRL and scroll to enlarge further.
Please notice that the camera needs to be connected to an external 12V power supply to implement the cooling function. ZWO recommends you use a 12V at 3A DC adapter (5.5 by 2.1 mm, center pole positive) or lithium battery with an 11 to 15V to power the camera.
USB3.0 and 256M DDR3 Memory
The ASI294MM Pro is equipped with a USB 3.0 transmission interface and a built-in 256MB(2Gb) DDR3 cache to ensure stable and secure data transmission. Under long exposures, it effectively avoids frame dropping and greatly reduces the glow effect caused by slow reading speed.