ZWO ASI4400MC Pro Cooled Color Full-Frame Camera

A 44.7 MP Full-Frame (36mm x 24mm) Imaging Platform

The core of the ASI4400MC Pro is its 36mm x 24mm Sony IMX366 BSI CMOS sensor, which provides a 43.3mm image diagonal. This full-frame format suits the largest deep-sky objects, like the North America Nebula (NGC 7000) or the Andromeda Galaxy (M31), in a single frame with wide-field refractors. With an 8192 x 5460 pixel array, the camera delivers the high resolution required for large-format prints and significant cropping flexibility, allowing you to isolate smaller targets within a vast starfield.

A 74.6k e- Full Well Capacity with 14-Bit ADC

The ASI4400MC Pro's 74.6k e- full well capacity lets each 4.4µm pixel collect a large charge before saturating, which helps maintain color and detail in bright stars within clusters like the Pleiades (M45) or the dense core of the Orion Nebula (M42). With the 14-bit ADC, dynamic range is over 13 stops, so a single exposure can hold bright highlights and faint shadow detail without clipping.

80% Peak QE and 1.1e Read Noise

High sensitivity is achieved through the sensor's back-illuminated architecture, which delivers a peak Quantum Efficiency (QE) of 80%. This ensures that a majority of incoming photons are converted into signal. To keep that faint signal clean, the camera's circuitry produces a minimum read noise of just 1.1e. When the gain setting reaches 136, the camera automatically engages High Conversion Gain (HCG) mode, which greatly reduces read noise while maintaining full dynamic range, which helps with faint targets.

30-35°C Cooling with Anti-Dew and Glow Suppression

Long-exposure astrophotography requires active thermal management to control noise. The ASI4400MC Pro uses a two-stage thermoelectric cooling system that lowers the sensor temperature by 30-35°C below ambient. ZWO tests this at 30°C ambient; the lower the ambient temperature, the smaller the differential, and ZWO does not recommend operation below -20°C. The cooling greatly reduces dark current and thermal noise. Further enhancing image quality are two key features:

• Glow Suppression: ZWO's proprietary Glow Suppression significantly reduces CMOS sensor glow but does not eliminate it; a small amount may remain and, with dark-frame calibration, it has no impact on the final image.
• Anti-Dew Heater: A built-in polyimide heater bonded to the UV-IR cut protective window prevents dew and frost. It draws about 5 watts and can be turned off in software to save power and reduce the load on USB hubs and external power supplies.

512MB DDR3 Buffer for 8.3 FPS Stable Transfer

Transferring a 44.7 MP, 14-bit image file is a data-intensive task. The ASI4400MC Pro includes a 512MB DDR3 memory buffer behind its USB 3.0 interface. This gives fast, stable transfer while reducing the risk of dropped frames or transmission errors. Full-resolution frames download at up to 8.3 FPS.

17.5mm Back Focus and Built-in Tilt Adjustment

Properly integrating the camera into your optical train is straightforward. The ASI4400MC Pro has a standard 17.5mm back focus distance and an M54 female thread interface. With the included M54-M48 21mm and M48-M48 16.5mm spacers you reach 17.5 + 21 + 16.5 = 55mm, the back focus that works best and that many correctors use. To ensure corner-to-corner sharpness across the large full-frame sensor, a built-in tilt adjuster with three push-pull screw sets lets you fine-tune the sensor's alignment with your telescope's optical axis, correcting slight tilt that makes stars look elongated or soft toward the edges.

The Advantage of a Bayer Matrix Sensor

As a one-shot color (OSC) camera, the ASI4400MC Pro uses a Bayer filter matrix over its sensor to capture red, green, and blue data simultaneously in a single exposure. This simplifies the imaging workflow significantly compared to a monochrome camera, which requires separate exposures through multiple filters to create a color image. For imagers who want full-color results without a filter wheel and monochrome filter sets, the ASI4400MC Pro keeps the workflow simple.

ASI4400MC Pro vs. ASI6200/2400MC Pro: Pixel Size and Dynamic Range

The ASI4400MC Pro sits between ZWO's ASI6200MC Pro and ASI2400MC Pro full-frame cameras.

• vs. ASI2400MC Pro: The ASI2400MC Pro sits on the larger-pixel side of the ASI4400MC Pro; the ASI4400MC Pro gives 44.7 MP for more cropping room.
• vs. ASI6200MC Pro: The ASI6200MC Pro has higher resolution at 61.2 MP with smaller 3.76µm pixels. The ASI4400MC Pro has larger 4.4µm pixels with a 74.6k e- full well, which helps bright stars hold their color.

A 1.5 lbs Body with 12V DC Power System

The camera body weighs 700g (1.5 lbs). External power supplies are needed for all ASI cooled cameras; use a 12V DC adapter rated 3A to 5A (5.5x2.1mm, center pole positive) or an 11-14V lithium battery; the camera can also be powered from an ASIAIR. A supply outside this voltage range will probably cause irreparable damage. The camera also has two USB 2.0 ports for connecting other devices as needed, such as a guide camera.