ZWO ASI585MM Mono

Sony IMX585 Sensor: 91% Peak QE from a 1/1.2" Monochrome Chip

At the core of the ASI585MM is a Sony STARVIS 2 sensor designed for extreme low-light sensitivity. The monochrome design removes the Bayer matrix, allowing every one of the 8.29 million pixels to capture the full luminance signal, resulting in a significant increase in detail and signal-to-noise ratio over a color equivalent. This raw sensitivity, quantified by its 91% peak QE, allows you to capture fainter details with shorter exposures, a key advantage when imaging planets or using narrowband filters for EAA.

46.9 FPS at 8.29 MP: Sustained Transfer with a 256MB DDR3 Buffer

Planetary imaging relies on "lucky imaging"—capturing thousands of frames to freeze moments of steady atmospheric seeing. The ASI585MM captures full 3840 x 2160 frames at 46.9 FPS, a rate that would overwhelm a direct USB connection. To solve this, a 256MB DDR3 memory buffer ensures stable, drop-free data transmission to your computer, preserving the integrity of your capture session. This high-speed capability, combined with the camera's Zero Amp Glow design, produces clean, stackable video files essential for resolving fine details on Jupiter's cloud bands or in the Cassini Division of Saturn's rings.

ASI585MM vs. ASI585MC: Monochrome Sensitivity vs. One-Shot Color

The primary difference between the ASI585MM (Monochrome) and its sibling, the ASI585MC (Color), lies in how they capture light. The color version offers the convenience of capturing a full-color image in a single shot, which is ideal for quick setups. However, the ASI585MM provides superior raw data for the discerning imager.

• Higher Resolution & Sensitivity: Without a color filter array, the ASI585MM uses every pixel for luminance, delivering a sharper, more detailed image and capturing more signal in the same amount of time.
• Narrowband Imaging: The monochrome sensor is the only way to effectively use specialized narrowband filters (H-alpha, OIII, SII) for imaging emission nebulae, a capability the color camera lacks.
• Trade-off: Achieving a color image with the ASI585MM requires a filter wheel and LRGB filters, adding complexity and cost to the imaging train. For maximum detail, the monochrome version is the clear choice; for simplicity, the color version is more direct.

6.5mm / 17.5mm Back Focus and Physical Connections

The ASI585MM provides flexible connection options for any optical train. A standard USB 3.0 port provides the 5Gbps bandwidth needed for high-frame-rate captures, while an ST-4 port allows direct connection to a mount for autoguiding. The camera body features native back focus distances of 6.5mm and 17.5mm, accommodating different accessory configurations. The 17.5mm spacing is standard for use with filter wheels and off-axis guiders, while the 6.5mm option is ideal for setups with strict spacing requirements, such as when used with specific focal reducers or camera lenses.