ZWO ASI461MM Pro Monochrome Medium Format Cooled Astro Camera - ASI461MM-P

The ZWO ASI461MM Pro uses the Sony IMX461 medium format, back-illuminated sensor with a pixel size of 3.76um, native 16-bit ADC with 65,536 levels and high quantum efficiency.  This amazing camera features very low readout noise of 1.0e and nearly zero visible fixed pattern noise.

ZWO ASI461MM Pro Medium Format Camera Highlights...

The ZWO ASI461MM Pro is a 100MP medium format camera with a large sensor size of 44mm x 33mm and a high resolution of 11656 * 8750.  The 3.76um pixels accommodate an impressive full well capacity of 50.3ke.  When at Bin2 mode, you can get an even larger full well capacity of 198ke and a larger pixel size of 7.5 um.

The Sony IMX461 has a back-illuminated CMOS sensor to improve sensitivity and noise reduction for better image quality when compared to conventional front-illumination structures.  Because metal wiring and transistors have been moved to the back of the silicon substrate instead of the front, more light can reach each pixel due to the lack of those obstacles.  

Please Note: All ZWO cooled (Pro) cameras will require an external 12V DC power source in order to operate properly and run the TEC cooler. You have three options:

1. Buy a 12V DC Power Supply with a minimum of 3 amps; we recommend the ZWO power supply listed at the end of this page.

2. Buy the ASIAir and use the DC Out port to run your camera.

3. Buy an external 12V DC battery like the Celestron PowerTank or equivalent.

It is important to know that your computer may not recognize your camera or operate correctly if you just use the USB 3.0 cable alone. You will want to connect whichever 12V DC power source you choose into your computer as well.

Native 16bit ADC

The ZWO ASI461 Pro camera has true 16-bit ADC, which means it really can achieve a dynamic range output of 14 stops.  This translates to improved image sharpness and contrast plus smoother and more natural contrast gradients.

HCG Mode

The HCG high gain mode is turned on automatically when the gain value is set to 100.  With HCG turned on, the readout noise is greatly reduced, while leaving the dynamic range virtually unchanged.  For DSO imaging, it is recommended to use Gain 0 or 100.

Zero Amp Glow

Traditional CMOS sensors produce a weak infrared light source during operation which is quite often seen in the corner of uncalibrated images as tell-tale signs of amp glow.  You won't have to worry about amp glow with the ASI461MC Pro, even when using high gain during long exposure images, however, as ZWO uses zero amp glow circuitry.

Anti-Dew

The ASI461MM Pro comes with a polyamide heater that sits on top of the protective window.  The heat provided avoids dew issues, but if you don't need it, the 5W dew heater can be turned off using software. Note:  Anti-dew heater below shown on another Pro model.

Two-Stage Cooling

With its built-in two stage TEC cooling, the ASI461MM Pro can lower the sensor temperature to more than 35 degrees Celsius below ambient temperature, greatly reducing dark current generation and sensor noise.

The unique dark current suppression technology can further reduce dark current noise.  When it is cooled to 0ºC, the dark current noise can be as low as 0.003e/s/pix.  This means a 300 second exposure will only cause 0.7e- of dark current noise, which is even lower than the camera's read noise!  If the cooling temperature reaches -20ºC, the dark noise can drop to an amazing 0.00024e/s/pix!

USB3.0 & 512M DDR3 Memory

The ZWO ASI461MM Pro uses a USB 3.0 transmission interface and is equipped with a built-in 512MB DDR3 cache to ensure stable secure data transmission.  During long exposures, it avoids frame dropping and greatly reduces glow effect caused by slow read speed.

Specifications

Sensor:  Sony Back-Illuminated IMX461

Sensor Size:  33mm x 33mm, Medium Format

Resolution:  11656 x 8750, 100MP

Pixel Size:  3.76um

ADC:  16-bit

Read Noise:  as low as 1.0e

Cooling Temperature:  35ºC

DDR3 Buffer:  256MB

Back Focus Distance:  17.5mm/22.5mm

Shutter:  Rolling

Exposure Range:  32us-2000s

Window:  D79.3-4 AR

Transmission Interface:  USB 3.0

Frames Per Second:  3.77

Full Well:  50.3ke

Quantum Efficiency:  91%

Weight:  910g

Supported OS:  WIN7/8/10 32 & 64, Linux, Mac