ASCOM/INDI compatible autofocuser.

(2 customer reviews)


We are striving to provide the astrophotographers across the globe with affordable autofocusing solutions, which can greatly improve the automation aspect of the capture process.

Based on your feedback and our experience with AF1/AF2, we have developed an upgraded version of our autofocuser. It is based on newer technology, boasting a stealth drive feature for minimal noise and vibration. Apart from the smoother motion, it also provides more accurate movement with microstepping down to 1/256. Enclosure was also optimized for easier assembly, but of course retained backward compatibility with every existing adapter. AF3 is also ASCOM/INDI compatible, just like AF1 and AF2.


  • ASCOM supported
  • INDI supported
  • INDIGO supported
  • TheSkyX Pro X2 Focuser Plugin
  • custom step size
  • speed control
  • current control
  • hand controller (optional)
  • temperature probe (optional)
  • settle buffer option
  • compact design (<motor type>: <dimensions>):
    • AF3: 44.5mm x 48.5mm x 50.2mm
    • AF3s: 44.5mm x 48.5mm x 66.2mm
    • AF3s+: 44.5mm x 48.5mm x 88.2mm

In the box

  • AF3 autofocuser (44.5 x 48.5 x 50.2)
  • MXL 20 teeth pulley
  • micro USB cable
  • OPTIONAL: hand controller
  • OPTIONAL: temperature sensor


power adapter: 12V – 14V MAX (1A min) with 5.5mm x 2.1mm plug (not included in the box)


Microfocus belt drive

By connecting the motor pulley directly to the microfocusing knob, we are trying to make attaching the autofocuser as seamless as possible. This method is quite unintrusive, as it does not require focuser axis knob dissasembly, attaching directly to the axis shaft via coupler, etc. In our experience, belt slipping is a non-issue due to little force required. If the belt tension is appropriate, autofocusing works like a charm. This approach also has following pros:

  • compact mounting balance-wise in comparison to shaft mounting, which protrudes away from the telescope tube.
  • driving microfocusing knob does not require a lot of force. This means that autofocuser motor can be quite small and does not require gearbox.
  • if you racked the focuser in/out and keep on moving the motor by mistake, it is not strong enough to damage any parts of the focuser shaft (motor starts skipping steps). With coupler connected to the focuser axis directly this could not be the case. Usually stronger motor or even a gearbox is involved to drive the shaft directly. This could result in damage to the gearbox, coupler or in worse case focuser itself.

Configure microfocusing knob kit










2 reviews for AF3

  1. Mark Tweedie (verified owner)

    This was my first electronic focuser and has proved to be an excellent choice. For astrophotography, once I got the parameters set up correctly in Ekos it has performed flawlessly and quickly. It is completely silent in use. I also purchased the hand controller and temperature monitor. The hand controller is simple and effective to use and totally transforms the focusing when doing visual observation – completely vibration free and superbly precise! I had a small problem fitting the adapter for the Skywatcher 80ED DS Pro but Pavle was super responsive and helpful and the issue was resolved quickly. I originally planned to buy one focuser and switch it between scopes but it is not simple to do this in the dark so I will be buying another for the second scope. Often astro gear can be temperamental but I can honestly say that this is the soundest, most reliable piece of equipment I possess. Highly recommended.

  2. David Stadermann

    I ordered the AF3 for my Lacerta 8″ F4 Newtonian which has an excellent but uncommon focuser. Pavle was super responsive and designed a perfectly fitting custom adapter for my focuser to fit the AF3. It should be stressed that my focuser has no straight surfaces to fit conventional brackets plus not a lot possibilities to bolt down the adapter. However, Pavle quickly came up with a design and started printing.

    Once the package arrived, installation was easy and the AF3 was immediately recognised by KStars/EKOS in which DeepSkyDad is listed as a manufacturer. Note that in the current version of EKOS as by Feb.2022, one needs to change the Baud rate to 115000 which is also stated in the FAQs.

    This is also my first belt driven focuser as I previously used directly driven ones. I immediately acknowledged the benefits of belt driven vs direct driven like no disassembly of the focuser and no slack in coupling etc.
    Also, the AF3 can be conveniently powered by an additional 12V DC Y-cable I had anyway from my ASI1600 to power the heating and the camera itself. So no need for additional power lines on the scope. The AF3 runs very smooth in operation without any noticeable vibration or noises. I’d also recommend to get the temperature probe since this allows one to program an autofocus at specified temperature differences.

    So all in all a perfectly working solution which can be highly recommended even or better especcially for exotic equipment!

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