ZWO ASI662MM USB 3.0 Monochrome CMOS Astronomy Camera

ZWO ASI662MM USB 3.0 Monochrome CMOS Astronomy Camera

Precision Planetary Imaging for the Serious Observer

ZWO’s ASI662MM represents the latest generation of planetary imaging technology—compact, fast, and remarkably sensitive. Built around Sony’s IMX662 STARVIS 2 monochrome sensor, this uncooled camera delivers the responsiveness, low noise, and fine detail that high-resolution lunar and planetary work demands. Whether you’re resolving subtle atmospheric bands on Jupiter, tracing the rugged shadows along the lunar terminator, or using it as a precision guide camera in a deep-sky setup, the ASI662MM provides the clarity and reliability that advanced imagers expect.

Optical System / Sensor Performance

At the heart of the ASI662MM lies the Sony IMX662 rolling-shutter CMOS sensor—a 1/2.8-inch format, 2.07-megapixel array measuring 1920 × 1080 pixels. Each 2.9 µm photosite captures fine detail while preserving high quantum efficiency—an impressive 91 % QE peak—to ensure strong signal even in low-light conditions.

The IMX662 benefits from Sony’s STARVIS 2 back-illuminated architecture, which places all circuitry behind the light-sensitive layer, maximizing photon collection and dramatically improving signal-to-noise performance. Combined with a large 38 ke⁻ full-well capacity, the sensor maintains smooth gradients and rich contrast without overexposing bright planetary features or solar limb detail.

The camera automatically engages High Conversion Gain (HCG) mode when the gain reaches 252, reducing read noise while preserving a 12-bit dynamic range. The result is striking tonal separation across both bright and faint regions, ideal for stacked “lucky imaging” sequences.

Capable of capturing up to 107.6 frames per second in high-speed mode, the ASI662MM enables large image runs that freeze moments of atmospheric steadiness—turning fleeting clarity into sharp, high-definition planetary portraits.

Electronic Design and Data Handling

Fast imaging requires data integrity. ZWO equips the ASI662MM with a USB 3.0 SuperSpeed interface and a 256 MB DDR3 buffer, ensuring that every frame transfers cleanly without dropped packets or lag. Even when operating at maximum frame rate, this buffer stabilizes throughput, maintaining consistent exposure timing and preventing the faint image streaks that can result from bottlenecked data lines.

The camera’s internal electronics are engineered for silence—Zero Amp Glow hardware eliminates the bright edge flare seen in earlier CMOS designs. Because this is achieved at the hardware level, no software correction or additional calibration frames are required.

Typical read noise measures as low as 0.6 – 0.8 e⁻, depending on gain, placing the ASI662MM among the quietest planetary sensors in its class. Combined with its deep wells and high dynamic range, this makes for an image stream rich in usable data, minimizing post-processing time and maximizing final image quality.

Build Quality and Connectivity

The ASI662MM follows ZWO’s proven unibody aluminum design—machined, anodized, and thermally balanced for consistent performance. Its compact housing integrates a USB 3.0 Type-B port for data and power, along with a dedicated ST-4 guide port for direct mount control. This dual connectivity allows the camera to serve both as a primary planetary imager and as a precision autoguider in multi-camera setups.

A standard 1.25-inch nosepiece and M42 × 0.75 T-thread interface provide compatibility with virtually all telescope focusers, filter wheels, and barlow systems. The small 1/2.8-inch format keeps vignetting minimal and simplifies optical alignment across a wide range of instruments—from SCTs and Maksutovs to fast refractors optimized for planetary work.

Each camera ships with a USB 3.0 cable, an ST-4 guide cable, and a 1.25-inch T-thread adapter, so it’s ready to mount and image straight out of the box.

Performance Highlights

• Sensor: Sony IMX662 STARVIS 2 CMOS (1/2.8")

• Resolution: 1920 × 1080 (2.07 MP)

• Pixel Size: 2.9 µm

• Quantum Efficiency: ≈ 91 % peak

• Full-Well Capacity: ≈ 38 ke⁻

• Read Noise: 0.6 – 0.8 e⁻ (typical)

• Dynamic Range: 12-bit (HCG enabled)

• Frame Rate: Up to 107.6 fps

• Interface: USB 3.0 + ST-4 guide port

• Buffer Memory: 256 MB DDR3

• Amp Glow: None – hardware eliminated

• Back Illumination: Yes (SONY STARVIS 2)

• Weight: ~120 g (4.2 oz)

• Threading: M42 × 0.75 / 1.25-inch nosepiece

Practical Applications

The ASI662MM is built for speed and sensitivity—two traits central to lucky imaging. Its small pixels and high frame rate make it ideal for capturing the fleeting moments of perfect seeing needed for high-resolution planetary and lunar mosaics.

Yet its precision electronics also make it a superb autoguider. When paired with a larger imaging telescope, its high QE and low noise enable accurate corrections even on faint guide stars. The compact form factor, robust USB 3.0 link, and zero-glow circuitry ensure consistent tracking and stable calibration over long sessions.

Final Thoughts

ZWO’s ASI662MM Monochrome Camera distills years of sensor refinement into a single, affordable imaging tool. Its advanced STARVIS 2 architecture brings a leap in quantum efficiency, read-noise reduction, and full-well capacity over earlier generations, while the addition of onboard memory and zero-glow electronics make it dependable night after night.

For planetary imagers, it offers a finely tuned blend of speed, sensitivity, and tonal depth that captures the solar system in extraordinary detail. For deep-sky photographers, it doubles as a precise, reliable guider. However you choose to use it, the ASI662MM embodies the clarity, craftsmanship, and quiet confidence that define modern ZWO design.