ZWO Electronic Automatic Focuser EAF Pro

Precise telescope focusing – completely wireless

The ZWO EAF Pro combines precise motorized focusing with convenient wireless control. Bluetooth 5.0 and a built-in lithium battery allow the electronic focuser to operate without additional power or data cables, creating a cleaner astrophotography setup with less cabling around the telescope.

Its powerful stepper motor and 1:128 reduction gearing provide accurate and repeatable focus control. With a positioning resolution of approximately 2.812 µm per step and a load capacity of up to 5 kg, the EAF Pro is also suitable for demanding camera, filter wheel and accessory configurations.

Integrated focus buttons provide quick manual adjustment directly on the device. A power switch and status indicator are also built in. When used with compatible imaging software, the EAF Pro can perform fully automated autofocus routines.

Key features

• Wireless operation via Bluetooth 5.0
• Built-in lithium battery
• Precise stepper motor with 1:128 reduction gearing
• Positioning resolution of approximately 2.812 µm per step
• Load capacity of up to 5 kg
• Integrated manual focus buttons
• Built-in power switch and status indicator
• USB-C for power and wired communication
• Compatible with the ASIAIR App and ASIStudio
• ASCOM and INDI support
• Port for an optional hand controller or temperature sensor
• Compact and durable metal housing

Technical specifications

• Product: ZWO Electronic Automatic Focuser EAF Pro
• Motor: Stepper motor
• Motor step angle: 7.5°
• Reduction ratio: 1:128
• Resolution: Approximately 2.812 µm per step
• Maximum payload: 5 kg
• Communication: USB Type-C and Bluetooth 5.0
• Power supply: USB Type-C, 5 V / 500 mA, or built-in lithium battery
• Dimensions: 41 × 52 × 73.4 mm
• Weight: 258 g
• Manual focus buttons: Yes
• Power switch: Yes
• Status indicator: Yes
• Software support: ASIAIR App, ASIStudio, ASCOM and INDI
• Port for an optional hand controller or temperature sensor: Yes

Battery life

Under ZWO laboratory test conditions, the EAF Pro operated for up to seven consecutive nights. Testing was performed at room temperature with two focusing operations per hour and eight hours of use per night. Actual battery life may vary depending on use and ambient temperature.

Important Compatibility Information

Fully wireless operation requires a Bluetooth-compatible ASIAIR system. Wireless control is supported by the RK version of the ASIAIR Plus and compatible ASIAIR camera models. The EAF Pro’s built-in battery supplies power to the focusing motor.

With the CM4 version of the ASIAIR Plus, the EAF Pro can be controlled through a wired USB connection. The motor can still be powered by the built-in battery, but the USB cable is required for data communication. Bluetooth control is not supported by this ASIAIR version.

The ASIAIR Plus hardware version can be identified by its device suffix:

• “ASIAIRPLUS”: RK version; Bluetooth connection supported
• “RPICM4”: CM4 version; USB connection required

The first-generation ASIAIR, ASIAIR Pro and ASIAIR Mini do not support a wireless connection to the EAF Pro. These models may also be subject to USB power-output limitations.

For Takahashi, Celestron C8 and C11 telescopes, ZWO recommends using a 4 mm flexible coupling because the new EAF generation is not fully compatible with the 5 mm coupling.