What comes in the box with the GEMINI EAF?

Upon opening the box I was greeted with a focuser itself, mounting tools, a remote control, a signal receiver and a temperature sensor. On my desk: the unit, an L-shaped bracket, three flexible couplings, screws and washers in a bag, a USB A-to-B cable, the IR receiver and the temperature probe on leads, and the white eight-button remote.

Does the GEMINI EAF work with NINA and the ASIAIR?

It is supported by NINA, with ASCOM and INDI drivers for SharpCap, KStars and other programs. The ASIAIR will not drive it: ZWO only allows its own electronic focuser.

How hard is the GEMINI EAF to fit?

That was the so called hard part, but it really didn't take very long. The coarse knob comes off its shaft, a coupling goes on, the unit goes onto the coupling and the bracket screws to the focuser body.

How much does the GEMINI EAF cost?

The prices I recorded: $82 at TeSeek (US), in stock; $56 at AliExpress (LittleLight Store), Global, listed.

What have I not tested on the GEMINI EAF?

I have not recorded an autofocus run, backlash or temperature-compensation readings with the GEMINI EAF.

GEMINI EAF review: the budget autofocuser that beat the ZWO EAF

Where does it rank on our leaderboard

Nine of the 46 accessories on my board, against price
Rank	Accessory	Stars for Your Buck	Recorded UK price
1	GEMINI EAF	100 out of 100	£42
2	Generic Dew Heater	93 out of 100	£9
10	MeLE MiniPC	84 out of 100	£490
18	Smartphone eyepiece mount	77 out of 100	£55
25	ZWO 7x2″ Filter Wheel	71 out of 100	£398
28	ASIAIR Mini	64 out of 100	£215
36	Celestron 2x Barlow	46 out of 100	£135
45	SKY ROVER 2x54 Binoculars	28 out of 100	£139
46	365 Solar Telescope Cover	5 out of 100	£73

Contents

01 Where does it rank on our leaderboard
02 Specifications and features
03 In use
04 Captured with it in the train
05 Fitting it in four steps
06 In my words
07 Watch it in my videos
08 Should you buy it?
09 Questions and more about this review

In 30 seconds

Stars for Your Buck 100/100

Reviewed 18 Dec 2024 Updated 29 Sep 2026

Rank: #1 of 46 accessories
Verdict: Damon's pick

Written by Damon Scotting 4 min read

Buy it if

Your telescope has a coarse focus knob on a shaft and you want autofocus without a big spend.
You want a remote control and a temperature probe in the box.
You run NINA, SharpCap or another ASCOM or INDI program.

Skip it if

You run your rig from an ASIAIR: it only drives ZWO's own focuser.
You need it this week: delivery from AliExpress can take about three weeks.

“A fabulous little focuser, with its own remote control and a temperature sensor in the box.”

Specifications and features

Against the accessories I have reviewed

Compare with

GEMINI EAF reviewed #1 of 46	ToupTek EAF #20 of 46	Altair EAF #26 of 46	ZWO EAF #33 of 46	ZWO EAF (legacy) #40 of 46
Recorded UK price	£42	£170	£139	£199	£199
Stars for Your Buck	100/100	75/100	70/100	51/100	44/100
Model	GEMINI Automatic Astro Focuser Pro	AAF	AAF-UNIV	EAFN, the standard Type-C EAF	EAF with a USB 2.0 Type-B socket, powered over USB
Motor	35 high-torque stepper	35 mm stepper	not recorded	Stepper, 7.5 degree step angle, 1:128 reduction	35 mm stepper, 7.5 degree step angle, 1:120 reduction
Steps	3,840 per rotation	not recorded	5,760 minimum angular increments per revolution (derived)	6,144 nominal full steps per output-shaft revolution (derived)	5760
Power and data	USB 2.0 Type-B, 5 V	USB Type-C, 5 V	USB Type-C, 5 V	USB Type-C, 5 V 500 mA	USB 2.0, powered by the USB cable
Accessory socket	TEMP and HBX jacks	TEMP/HBX jack for the temperature sensor or hand controller	TEMP/HBX jack for the temperature sensor or hand controller	Temperature sensor or hand controller	3.5 mm jack for a temperature sensor or hand controller
Remote control	Included, eight-button IR remote with receiver	Included, hand controller	Included, hand controller	Sold separately	Sold separately
Temperature sensor	Included	Included	Included	Sold separately	Sold separately
Software	ASCOM and INDI (NINA, SharpCap, KStars, MDL); not the ASIAIR	ASCOM and INDI, ToupTek AstroStation	Altair ASCOM driver (NINA, SharpCap and other ASCOM programs)	ASIAIR, ASIStudio, ASCOM and INDI	ASIAIR, ASIStudio, ASCOM and INDI
In the box	Focuser, L-shaped bracket, three flexible couplings, screws and washers, USB A-to-B cable, IR receiver, temperature probe, remote	Hand controller, temperature sensor, two mounting plates, flexible couplers, USB cable	Focuser, universal bracket with screws and washers, 4, 5, 6 and 7 mm couplers, temperature sensor, USB cable, hand controller	EAFN; bracket; four couplers; 2 m USB-C cable; five spacers; mounting screws; two hex keys; quick guide	EAF body, bracket, flexible coupling, spacers and screws, M4 and M5 wrenches, USB 2.0 cable

In use

Out of the box

Beside the Askar SQA85

The remote

TEMP, USB2.0 and HBX

Plugging in the probe

Run from a power bank

Captured with it in the train

One target

NGC 2237 Rosette Nebula, ASI2600MC Duo

Integration: 35 min (7 x 300 s)
Field: 3.24 x 2.17 degrees
Telescope: Askar SQA85
Camera: ZWO ASI2600MC Duo
Mount: ZWO AM5N
Target: NGC 2237 Rosette Nebula
Type: Emission nebula with an open cluster
Location: Bortle 6.8 (in my garden)

Fitting it in four steps

Four steps from my video

Off comes the coarse knob

Loosen the tightening screw inside the coarse adjustment knob until the knob just slides off.

A coupling onto the shaft

Select one of the three flexible couplings provided in the box, loosen its screws and tighten it onto the focuser shaft.

The focuser onto the coupling

Do the exact same thing to attach the focuser to the other end of the flexible coupling.

The bracket takes the torque

Fix it in with the mounting bracket so the focuser can apply the necessary torque, with the washers from the little bag.

In my words

“The remote control is very handy and the temperature sensor is super useful.”

From my video review

“And yeah, it runs and responds very smoothly. A worthy adversary to the ZWO EAF and the ToupTek AAF, but available for far less.”

From my video review

Watch it in my videos

CHEAP v.s EXPENSIVE Telescope Gear?! · published 18 December 2024 · 14:15 · Watch on YouTube · 66,551 views, 1,854 likes on 2 Oct 2026

Jump to

0:33 What an electronic autofocuser does
1:52 The ZWO EAF, and a cheaper alternative
2:14 In the box: remote, receiver and temperature sensor
2:47 Onto the Askar SQA85
3:07 The 60-second fitting walkthrough
4:17 The remote, the probe, the power-bank test and NINA
5:08 Cheap comes out on top with ease

Transcript of the video 912 words · 7 chapters · searchable

Press a time stamp to play from there.

0:33 What an electronic autofocuser does

0:34 First up, we need to focus. 0:34 This is a make or break aspect of our observations. 0:38 The tiniest adjustment in your focus can have the most dramatic effects on your images. 0:43 So do we leave it up to our naked eyes to squint and tell us what looks like the sharpest view? 0:47 Or do we utilise the assistance of autofocuses like these? 0:47 Electronic autofocuses have been around for years now. 0:54 The first editions simply employed clockwise and anti-clockwise adjustments at variable speeds. 0:59 But then they leveled up as they were able to function alongside the rest of our gear. 1:03 You can now correct the focus of your scope via your computer. 1:06 In fact, you can even gauge the temperature outside and modify the focus accordingly. 1:11 But perhaps the biggest step up is that you can now ask your electronic focuser to perfectly pinpoint your stars for you. 1:16 You no longer have to make your own subjective decision on what looks best. 1:20 The focuser will use its own mathematical formula to figure it out for you. 1:24 As nights go on, the temperature can vary, so too can a lot of things, including the perfect focus of your telescope. 1:31 With an EAF you can set it to automatically correct the focus as often as you like. 1:36 So they are undeniably super helpful pieces of kit, and given the simplicity behind the structural design and its purpose, they must be relatively cheap, right? 1:46 Come on this is Astrophotography we are talking about, companies will charge you an extra 100 pounds for a power bank simply because they know some of you can afford it.

1:52 The ZWO EAF, and a cheaper alternative

1:52 I've recently had the pleasure of using a ZWO EAF, which is arguably one of the top focuses available on the market. 1:57 Simple design, powerful function. 2:01 Which is why users will fork out almost $200 to get one. 2:05 But what if there was a cheaper alternative available? 2:05 Perhaps at a cost of 69 pounds. 2:09 This is our first affordable alternative the Gemini autofocuser.

2:14 In the box: remote, receiver and temperature sensor

2:14 For a pre-taxed cost of £69 I have received a wonderful piece of kit that comes with some very useful accessories of its own. 2:20 Upon opening the box I was greeted with a focuser itself, mounting tools, a remote control, a signal receiver and a temperature sensor. 2:28 These last two components are not included with the ZWO EAF but can be purchased for an additional fee of... 2:33 that's not great. 2:33 Yeah you could almost buy a second german eye focuser for that. 2:40 I am starting to get a bit more experience now with focusers in fact I've recently been using a ToupTek AAF, which costs just over half the price of the ZWO EAF.

2:47 Onto the Askar SQA85

2:48 In keeping with the matching colour schemes I'm going to attach my Gemini focuser to my newest scope the Askar SQA 85. 2:55 Its space grey colour scheme fits perfectly alongside the Gemini. 3:04 In case you were wondering how complex it is to install the focuser here's a 60 second walkthrough.

3:07 The 60-second fitting walkthrough

3:07 First thing you're going to do is find the tightening screw located inside the coarse adjustment screw of your telescope and loosen that up a little bit until the coarse adjustment just slides off. 3:19 Now we're looking to simply replace this with our autofocuser, so in order to do so we're going to select one of the 3 flexible couplings provided in the box. 3:23 Then we're going to be sure to loosen the screws properly before tightening them to secure it to our focuser. 3:30 And as you can see, we're already halfway through the process. 3:35 Next do the exact same thing in order to attach the focuser to the other end of flexible coupling. 3:38 Lastly, in order to ensure the electronic autofocuser can apply the necessary torque to your telescope focuser, we need to fix it in using the mounting bracket provided. 3:47 Don't forget to also use the washers that are included in this little bag. 3:58 And there we go! 4:06 That was the so called hard part, but it really didn't take very long. 4:09 It certainly looks the part, and doesn't at all stand out in comparison to the blue and white hybrid tube tech ascar setup or the red and black ZWO rig.

4:17 The remote, the probe, the power-bank test and NINA

4:17 So let's plug in the additional attachments. 4:20 The remote control is very handy and the temperature sensor is super useful. 4:23 It's nice to see both of these included in the listing, or at the very worst an additional $8 fee for the pair of them. 4:27 That's excellent value especially compared to, well, yeah. 4:32 It certainly looks the part, relatively similar dimensions and weight. 4:32 The big difference of course is the cost. 4:37 There is a huge disparity between astrophotographers saying they have a budget of $200 for a telescope and then you have some of us dropping $200 alone on this little box that enacts such a simple process. 4:45 I plugged the data cable into a power bank and tested to see how well it responded to the remote control. 4:54 And yeah, it runs and responds very smoothly. 4:54 A worthy adversary to the ZWO-EAF and the Tooptech AAF, but available for far less. 5:00 It is supported by NINA and you can download the driver from the product page that I've linked in the description below.

5:08 Cheap comes out on top with ease

5:08 So there we go, product number one of the cheap vs expensive tests, and cheap comes out on top with ease. 5:15 Next up we have a race between two of the fastest scopes in the galaxy.

Check out more videos on the GEMINI EAF

Askar SQA85 Review

20 Jan 2025

Should you buy it?

100/100 Stars for Your Buck

Pros

A remote control and a temperature sensor come in the box.
It worked flawlessly; I had no issues with it at all.
It works with every program I have tried it with.
One USB cable carries power and data at 5 V: a power bank runs it.
It fits in minutes with a coupling and a bracket from the box.

Cons

The ASIAIR will not drive it: ZWO's controller runs only ZWO's own focuser.
No UK or US dealer stocks it: it comes from AliExpress or the maker's own store, and delivery can take about three weeks.
A USB 2.0 Type-B socket, where newer focusers have moved to Type-C.

It runs and responds very smoothly: a worthy adversary to the ZWO EAF and the ToupTek AAF, but available for far less.

Who the GEMINI EAF is for

Owner of a premium refractor

Buy

A budget focuser that works flawlessly on a premium refractor such as the Askar SQA85.

Planetary imager on a Schmidt-Cassegrain

Buy

The remote steps the focus a couple of steps at a time, which is how I find the sweet spot on Jupiter.

Owner of a helical-focuser telescope

Buy

It drives a helical focuser such as the SVBONY SV545's as well as a rack and pinion.

Imager on a tight budget

Buy

Autofocus, a remote and a temperature probe for far less than the ZWO EAF.

ASIAIR user

Skip

The ASIAIR drives only ZWO's own focuser: my recommendation is the ZWO EAF.

Needs it this week

Skip

Delivery from AliExpress can take about three weeks; a UK or US dealer's focuser arrives sooner.

Three alternatives I have reviewed

Questions and more about this review

Reviewed by

Damon Scotting

The Telescope Man Verified

BSc (Hons) Physics with Astrophysics and Cosmology, Loughborough University PGCE / QTS, University of Nottingham

About Damon About Damon Damon Scotting is The Telescope Man. He holds a BSc (Hons) in Physics with Astrophysics and Cosmology from Loughborough University and a PGCE with QTS from the University of Nottingham, and taught physics in secondary schools before becoming an astronomy creator. He is a contributing writer for BBC Sky at Night Magazine and the author of 42 Wonders of Our Night Sky, and his photograph of the galaxy M100 with the dwarf planet Ceres was Highly Commended in the Astronomy Photographer of the Year 2024 competition run by Royal Observatory Greenwich. He has appeared on the BBC's Blue Peter. More than 750,000 people follow his astronomy channels on YouTube, Instagram and TikTok, and he has reviewed more than 140 telescopes, mounts, cameras, filters and accessories hands-on for this site. More about Damon · How I test · Damon's book

I review all kinds of gear: most of it I buy, some is gifted and some is loaned, and all of it is reviewed the same way. How this site is funded

Five questions, answered

Questions about the GEMINI EAF

Reviewed 18 December 2024 ·Updated 29 September 2026

I review all kinds of gear. Most of it I buy, some is gifted and some is loaned, and all of it is reviewed the same way: no company sees or approves a review before it is published. Shop links marked Ad are affiliate links: I earn a commission when you buy through them, at no extra cost to you. How this site is funded

What comes in the box with the GEMINI EAF? Upon opening the box I was greeted with a focuser itself, mounting tools, a remote control, a signal receiver and a temperature sensor. On my desk: the unit, an L-shaped bracket, three flexible couplings, screws and washers in a bag, a USB A-to-B cable, the IR receiver and the temperature probe on leads, and the white eight-button remote. From my video review In use ↓
Does the GEMINI EAF work with NINA and the ASIAIR? It is supported by NINA, with ASCOM and INDI drivers for SharpCap, KStars and other programs. The ASIAIR will not drive it: ZWO only allows its own electronic focuser. The specifications and the comparison table ↓
How hard is the GEMINI EAF to fit? That was the so called hard part, but it really didn't take very long. The coarse knob comes off its shaft, a coupling goes on, the unit goes onto the coupling and the bracket screws to the focuser body. From my video review Fitting it in four steps ↓
How much does the GEMINI EAF cost? The prices I recorded: $82 at TeSeek (US), in stock; $56 at AliExpress (LittleLight Store), Global, listed. A record, not a live price The verdict, the readers and the sellers ↓
What have I not tested on the GEMINI EAF? I have not recorded an autofocus run, backlash or temperature-compensation readings with the GEMINI EAF.