ZWO EAF Pro – The Ultimate Upgrade in Automated Focusing for Astrophotography

The ZWO EAF Pro (Electronic Automatic Focuser Pro) takes astrophotography to the next level with a range of user-friendly upgrades. Now equipped with dedicated In/Out focus buttons, the EAF Pro allows you to manually adjust focus without the need for an external hand controller. This makes it ideal for those who occasionally view through the telescope visually or change components in the imaging train.

Built-In Battery for Cord-Free Operation

One of the standout new features is the integrated lithium battery, allowing the EAF Pro to operate without an external USB power source. This makes the focuser perfect for portable setups or grab-and-go astrophotography. A full charge lasts up to a week under normal use, adding unmatched convenience in the field.

Wireless Focusing via ASIAIR and Bluetooth

The EAF Pro now includes Bluetooth 5.0 wireless control, reducing cable clutter and the risk of snags during imaging sessions. Compatible with the ASIAIR app, ASIStudio, and ASCOM platforms, it delivers seamless wireless control for efficient and streamlined operation.

Strong Load Capacity for Modern Gear

With a maximum payload of 5kg (11lbs), the ZWO EAF Pro supports heavy astrophotography accessories, including rotators, filter wheels, and deep sky cameras.
You can focus confidently without worry of mechanical flex or focuser sag.

Industry-Leading Software Compatibility

The EAF Pro works with a wide range of astronomy software, including:

• ZWO ASIAIR

• ASIStudio

• ASCOM and INDI drivers

• NINA

• SharpCap

• FireCapture

• TheSky

• FocusMax
  …and many more. Whether you’re imaging planets or deep-sky targets, you’ll enjoy a smooth experience across platforms.

Micron-Level Focus Precision

At the heart of the EAF Pro is a high-precision stepper motor with a 1:128 reduction ratio, delivering reliable torque and sub-micron focus accuracy. This ensures razor-sharp star images and consistent performance, even during long imaging sessions or temperature swings.

How Autofocus Works with the EAF Pro

Focusing with the ZWO EAF Pro is simple and highly accurate. Start by manually achieving rough focus. Then, run an autofocus routine using ASIAIR or your preferred software. The focuser analyses star size across movements, generates a V-curve, and locks in the lowest point for optimal sharpness. It can also re-focus automatically after meridian flips, filter changes, or based on ambient temperature changes.

How to Install the ZWO EAF (Electronic Automatic Focuser)

Follow these simple steps to install your ZWO EAF Pro or Standard model onto your telescope for precise electronic focusing:

Step-by-Step Installation Guide

Step 1: Remove Existing Focus Knob
Detach the coarse focus knob from your telescope’s focuser to make room for the ZWO EAF installation.

Step 2: Fit the Focuser Coupling
Install the provided focuser coupling onto the focuser shaft. Use the supplied 2mm hex wrench to tighten the locking screw securely.

Step 3: Connect the EAF Motor Shaft
Align the flat section of the EAF motor shaft with the coupling’s locking screws. Tighten both screws firmly using the 2mm hex wrench.

Step 4: Mount the EAF to the Telescope
Attach the EAF unit to the bracket, then align and secure the bracket to the mounting holes on your telescope focuser using the included M4 screws. Ensure the bracket sits flush against the surface with no gaps and remains parallel to the focuser body for stability.

Step 5: Final Hardware Check
Verify that all screws and connections are tight. This completes the physical installation of the ZWO EAF.

Step 6 (For Curved Focusers Only):
If you’re using a curved focuser (as shown in the image below), simply use the original locking screw and three washers to secure the bracket. The built-in groove on the underside of the bracket allows a single screw to provide enough support.

Important Note: Shaft Compatibility for Takahashi and Celestron SCT Telescopes

ZWO has updated the EAF Pro and EAF-N models with a 4mm output shaft and coupling, replacing the older 5mm version. This change may affect compatibility for users with specialty brackets.

Compatibility Update

ZWO will soon include a 4mm coupling with these brackets to ensure proper fit:

• ZWO EAF Brackets for Takahashi (EAF-BRK-TK)

• EAF Bracket for Celestron C8/C9.25 SCT (EAF-C8-C925)

• EAF Bracket for Celestron C11/C14 SCT (EAF-C11-C14)

At present, these brackets still include the older 5mm coupling. However, ZWO has confirmed that the older coupling can work with the 4mm shaft under most conditions, though it may not be ideal for users requiring high precision.

Once we receive the updated brackets with 4mm couplings, we’ll update this page and product listings accordingly.

Good news: ZWO will continue to include both the 4mm and 5mm couplings, so you’re covered whether you’re using the newer or older EAF versions.

Mechanical Diagram