ZWO Electronic Filter Wheel EFW Gen2 - 7 x 36mm

7-Position Capacity for 36mm Filters

The internal carousel holds up to seven 36mm unmounted filters, providing enough capacity to house a full LRGB set and a 3-filter narrowband SHO set simultaneously. This eliminates the need to swap filters between targets, allowing for fully automated, multi-palette imaging sessions. The 36mm filter size is the optimal choice for cameras with APS-C format sensors, providing full sensor illumination without the cost or vignetting risk of undersized filters, or the unnecessary expense of 2" filters.

Redesigned Housing for 0 Light Leaks

This second-generation EFW features a redesigned body focused on eliminating internal reflections and stray light. A new slot-style closure and a fully sealed motor compartment prevent light from entering the housing, while included light-blocking pads replace older filter masks for a more secure, light-tight seal around the filters. These improvements ensure that long exposures, especially with narrowband filters, are protected from gradients and artifacts caused by stray light.

USB-Powered Simplicity with 2 Included Cables

The filter wheel is powered and controlled entirely through its USB-C port, drawing minimal power and requiring no separate 12V supply. This simplifies cable routing and reduces potential failure points at the telescope. ZWO includes both a 0.5 M and a 2 M USB-C cable, giving you flexible options for connecting to an ASIAIR, a camera's USB hub, or a computer.

• Native ASIAIR Control: Integrates seamlessly with the ZWO ASIAIR ecosystem for control via your smartphone or tablet.
• ASCOM Compliant: A standard ASCOM driver ensures compatibility with N.I.N.A., SGP, and other popular acquisition software on Windows.
• Direct Connection: Bolt-through holes allow for a rigid, direct attachment to ZWO cameras, creating a solid imaging train with minimal flexure.

ZWO EFW Gen2 vs. First-Generation EFW

This 2025 model introduces several key upgrades over the original ZWO EFW design. While both provide reliable filter changes, the Gen2 model is engineered for more demanding imaging applications.

• Stray Light Control: The Gen2's primary advantage is its superior light-leak protection, thanks to the redesigned housing and sealed motor. This is a critical improvement for imagers working under light-polluted skies or capturing faint signals.
• Connectivity: The move from a legacy USB port to a modern USB-C port provides a more reliable and easier-to-use connection, especially in the dark.
• Mechanical Precision: An upgraded stepper motor and internal mechanism deliver precise, repeatable filter placement, ensuring flats calibrate correctly every time.