ZWO EAF - Electronic Automatic Focusmotor - NEW 5V version

product code: ZWO-EAF-5V
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ZWO EAF - Electronic Automatic Focusmotor - NEW 5V version

ZWO EAF - Electronic Automatic Focusmotor

Introducting the new ZWO EAF, the lateset innovation from the engineers at ZWO. This electronic focuser enables precise, dynamic focus control for planetary and deep-sky imaging.

Standard Version: EAF body, flexible coupling, motor bracket, USB2.0 cable.

Advanced Version: EAF body, flexible coupling, motor bracket, USB2.0 cable, hand controller, temperature sensor.


Size: 60mm x 50mm x 40mm

Power port: new version powered via a 5V USB port

Data port: USB2.0 port

Weight: 277g

Capacity: 5kg

Mechanical Diagram

Additonal brackets for various focusers are under development.


A customer confirmed that the ZWO EAF-S is compatible with our Sharpstar 61EDPH.

Also, here is a report from another customer, Robin Berry, who purchased our very first EAF. Given that there is no official manual from ZWO at the time of his purchase, these notes might serve as a great practical intro for future users:

"Fitting to the SW Esprit 120 ED was easy enough but requires the drilling and tapping of two M4 holes in the base of the focuser.  As supplied the bracket only has one position to take a bolt (the left hand of the three in attached pic) and that really is not man enough to hold the unit in service.  The job was easy enough with the focuser unit removed from the scope.  Hope this helps as info for anyone else who asks.

Once fitted it works beautifully with the ASIAIR.  Hoping the autofocus update won’t take too long...

A couple of other points you may wish to bear in mind judging by the questions being asked on Fb and in the absence of any guidance from ZWO:-

  1. There is no clutch in the EAF.  This means that once fitted the manual focus cannot be used.  Attempting to do so is likely to damage the internals of the EAF.  It also means that, until the EAF handset is released, the telescope cannot be focused without using the ASIAIR.  The handset will provide a means of adjusting the focus via the EAF without using ASIAIR.
  2. The default step sizes in ASIAIR are not sufficient to give visible movement of the focuser.  This has led to a few public cries of “duff equipment” on Fb.  For initial testing I set Large Step to 1000 and Small Step to 50 in ASIAIR Focuser Settings.
  3. There has been one shout of SW Powertank wouldn’t power the EAF, but that will need checking out.  Mine runs fine from a Celestron Lithium Pro power source which is already powering the mount, ASIAIR and two cameras (one cooled).
  4. T J Connolly has put a good user guide to EAF usage on the ASIAIR Fb page."

Courtesy of Robin Berry

Above image: Courtesy of Robin Berry

Another example of fitting an EAF on a Skywatcher Esprit 120, this time without drilling...:

Above image: Courtesy of Damien Finlayson.

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Brand ZWOptical
Condition New
Product Code ZWO-EAF-5V