ZWO ASI585MM – High-Sensitivity Monochrome Planetary Camera with Zero Amp Glow

The ZWO ASI585MM is a professional monochrome planetary camera built around the latest Sony STARVIS 2 IMX585 back-illuminated CMOS sensor. This 1/1.2” format sensor offers an 8.29 megapixel resolution (3840 x 2160) with a 2.9µm pixel size, delivering exceptional detail for high-resolution solar and lunar imaging.

As the monochrome successor to the ASI485MC, the ASI585MM features numerous advancements, including:

• Zero amp glow, even during long exposures

• Lower dark current noise

• A full well capacity three times larger than its predecessor—up to 40,000 electrons—allowing superior dynamic range and improved highlight retention.

Sensor Performance and Sensitivity

Thanks to STARVIS 2 technology, the ASI585MM achieves a quantum efficiency (QE) of up to 91%, offering superb sensitivity across both the visible and near-infrared spectrum. This makes it an ideal choice for solar hydrogen-alpha, calcium-K, and near-IR imaging, especially when using narrowband filters.

Its resolution is four times greater than the popular ASI462MC, allowing more detailed captures of solar prominences, lunar surface textures, and planetary features.

High Frame Rate and Connectivity

The USB 3.0 interface delivers up to 5Gbps bandwidth, supporting 46.9 frames per second at full 8.29MP resolution in 12-bit normal mode. For optimal performance, especially at high frame rates, ZWO recommends using solid-state drives and high-performance systems with fast write speeds.

HCG Mode and Dynamic Range

The ASI585MM includes HCG (High Conversion Gain) mode, which automatically activates at a gain setting of 252 or higher. This feature:

• Dramatically reduces read noise to as low as 0.8e⁻

• Maintains a dynamic range close to 12 stops, ensuring excellent tonal balance across both bright and faint regions of your target.

Engineered for Clean Imaging

Unlike earlier CMOS designs, the ASI585MM features hardware-level anti-amp glow circuitry, ensuring clean, artefact-free images—particularly important when stacking hundreds or thousands of frames in solar or lunar workflows.

Summary Specifications

• Sensor: Sony IMX585 Monochrome CMOS (1/1.2” format)

• Resolution: 3840 x 2160 (8.29 MP)

• Pixel Size: 2.9µm x 2.9µm

• Full Well Depth: 40,000e⁻

• Quantum Efficiency: Up to 91%

• Read Noise: As low as 0.8e⁻ (HCG mode)

• Frame Rate: Up to 46.9 FPS at full res (12-bit)

• Amp Glow: None (hardware-suppressed)

• Interface: USB 3.0

Whether you’re capturing the fine texture of solar granulation, the detail of lunar craters, or experimenting with narrowband filters in IR, the ZWO ASI585MM offers an exceptional upgrade path for astrophotographers seeking high dynamic range, outstanding sensitivity, and the benefits of monochrome imaging flexibility.

Mechanical Diagram