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Autofocus without a cable, plus buttons right on the focuser
Why we like the EAF Pro:
- One less cable: a built-in battery and Bluetooth 5.0 let it focus with no wires at all. ZWO's test ran it for 7 nights of 8 hours, refocusing twice an hour, on one charge.
- Focus by hand when you want to: IN and OUT buttons on the body let you focus visually or rough in focus at the scope, with no phone or hand controller needed.
- Same precision as the EAFN: the 1:128 gear reduction moves the focuser in tiny, repeatable steps, and it handles up to 5kg (11lb) of camera and filters.
- What we tell customers: if your rig already has a USB hub and you never touch the focuser by hand, the EAFN does the same job for less. Pick the Pro for wireless setups, portable rigs and visual use.
The ZWO EAF Pro Electronic Auto Focuser is a motor that attaches to your telescope's focuser and turns it for you. Paired with an ASIAIR, a ZWO smart camera or a computer, it runs autofocus routines that measure star sizes and find best focus, then refocuses through the night as the temperature changes. It's the premium version of ZWO's new-generation EAF, adding a built-in lithium battery, Bluetooth, focus buttons, a power switch and a status light, and it weighs 258g (9.1oz).
Key specs: stepper motor with 1:128 reduction · 5kg (11lb) focuser load · Bluetooth 5.0 and USB-C · built-in lithium battery (about 7 nights per charge in ZWO's test) · IN/OUT buttons · ASCOM and INDI · works with ASIAIR · 258g
What it does for your images
- Autofocus in a couple of minutes: the ASIAIR or N.I.N.A. steps through focus, measures star sizes and lands on best focus.
- Refocus as it cools: set it to refocus after a temperature change, after a set number of frames, or after each filter change on a mono camera.
- Repeatable positions: save the focus position for each filter or camera and return to it in seconds.
- Sharper planets: fine-tune focus on Jupiter or Saturn from your phone or laptop without shaking the telescope.
How to install it
Remove one of your focuser's coarse knobs, slide the matching flexible coupling onto the focuser shaft, then attach the EAF Pro and its bracket to the focuser with the supplied screws. Four couplings in different sizes and five spacers are included, so the standard bracket fits most Crayford and rack-and-pinion focusers. Celestron SCTs and Takahashi refractors need a model-specific bracket (see below).
Connect it to the ASIAIR app over Bluetooth, or plug it in with USB-C, which also charges the battery. Software support includes ZWO's ASIAIR app and ASIStudio, plus ASCOM and INDI programs such as N.I.N.A., SharpCap, FireCapture, Sequence Generator Pro, MaxIm DL, TheSkyX and FocusMax.
ASIAIR power tip: a USB-C to USB-C cable from the ASIAIR's USB-C port carries data only. To charge or power the focuser from the ASIAIR, use one of its regular USB ports.
What to add for the best results
- ASIAIR Plus 256GB: autofocus is one tap in the app, and it connects to the EAF Pro over Bluetooth.
- ZWO EAF temperature sensor: lets your software refocus automatically when the temperature drops.
- ZWO EAF hand control: a wired paddle if you'd rather not reach for the focuser.
- EAF bracket for C8 and C9.25, C11 and C14 or Takahashi (required for those telescopes): each includes the 4mm coupler the new EAF needs.
ZWO EAF Pro vs. EAFN
| EAF Pro | EAFN | |
|---|---|---|
| Connection | USB-C and Bluetooth 5.0 | USB-C |
| Power | USB-C or built-in battery | Over USB-C |
| Focus buttons on the body | Yes | No (optional hand control) |
| Power switch and status light | Yes | No |
| Weight | 258g | 215g |
| Load capacity | 5kg (11lb) | 5kg (11lb) |
| Best for | Wireless and portable rigs, visual observers | Imaging rigs with a USB hub or ASIAIR |
See all ZWO EAF focusers and brackets.
What's in the box
- ZWO EAF Pro focuser body
- Standard mounting bracket
- 2m USB cable
- 2mm and 3mm hex wrenches
- Four flexible couplings in different sizes
- Four M4x8 and two M5x10 hex screws, and five spacers
- Quick guide
The temperature sensor, hand control and telescope-specific brackets are sold separately.
ZWO EAF Pro FAQ
Will it fit my telescope?
It fits most refractors and Newtonians with a Crayford or rack-and-pinion focuser using the included bracket and couplings. Celestron SCTs and Takahashi refractors need the matching bracket. If you're not sure, send us your telescope model and we'll tell you what you need.
How long does the battery last?
In ZWO's lab test at room temperature, it ran 7 nights of 8 hours with 2 focus runs per hour on one charge. Expect less in cold weather, and you can always run it from USB-C instead.
Does it work with the ASIAIR?
Yes, over Bluetooth or USB. Autofocus is one tap in the ASIAIR app. It also connects to ZWO's smart cameras over Bluetooth.
EAF Pro or EAFN?
Choose the Pro if you want fewer cables, use the focuser for visual observing, or move your rig often. Choose the EAFN if everything already runs through a USB hub.
Can I reuse a bracket from an older EAF?
The new EAF uses a 4mm shaft coupler instead of the older 5mm one, because ZWO changed the internal motor. The brackets we stock include the 4mm coupler. If you have an older bracket, ask us before reusing it.
Can I use it for visual observing?
Yes. The IN and OUT buttons on the body let you focus without touching the knob, which keeps the view steady at high power.
Specifications
| Motor | |
|---|---|
| Type | Stepper motor, 7.5° step angle |
| Reduction ratio | 1:128 |
| Precision | Micron-level |
| Maximum focuser load | 5kg (11.02lb) |
| Connections and power | |
| Interface | USB-C and Bluetooth 5.0 |
| Power | Built-in lithium battery, or 5V 500mA over USB-C |
| Battery life | About 7 nights (ZWO lab test: 8 hours per night, 2 focus runs per hour, room temperature) |
| Controls | IN and OUT buttons, power switch, status light |
| Accessory ports | Temperature sensor and hand controller (TEMP/HBX) |
| Software | ASIAIR, ASIStudio, ASCOM and INDI |
| Physical | |
| Dimensions | 41 x 52 x 73.4mm |
| Weight | 258g (9.1oz) |
| Shaft coupler | 4mm (new generation) |
| Warranty | 2 years (ZWO) |
| Model / SKU | ZWO-EAFPRO |