Autofocuser FAQ

While testing our units, we carefully write down every issue that arises and solution to it - from basic connectivity, firmware upgrade to more complex problems like focuser slip and play. In result, this section composed from development and testing experiance, gathered from countless nights through years of astrophotography in field. Should you have additional questions not listed here, please let us know!

What kind of power adapter can I use?

The most important is the voltage - use 12V. Using lower voltage will cause torque issues. Using higher voltage could damage the circuit. Current output of the power adapter should be 1A minimum, but can be more (it will not damage the autofocuser).

When I connect the autofocuser to computer, Windows does not recognize it. What can I do?

You probably need to install the CH340 driver for Arduino compatible boards to provide USB connectivity. You can download it here or from authors website.

How can I upgrade focuser firmware?

Please refer to the firmware upgrade instructions.

How can I use the autofocuser on Linux/Mac OS/BSD

You can use this autofocuser on non-Windows based system via INDI driver.

Focuser is recognized by Windows and virtual COM port is created. What now?

Next step is installation of ASCOM driver, so you can use the focuser with any of the automation programes, like SGPro. You can download the ASCOM driver here. You also need to install ASCOM platform.

I successfully installed new version of ASCOM driver, but old version is still being used. How can I fix it?

This happens sometimes, expecially if driver is in use and you run ASCOM driver setup in meantime. ASCOM closes program using it, but in some cases it still does not work. To install new version of driver, delete the following dll file: C:\Program Files (x86)\Common Files\ASCOM\Focuser\ASCOM.DeepSkyDad.Focuser.dll and run installer again.

I successfully installed new version of ASCOM driver, but now focuser will not connect. How can I fix it?

First check if you chose the correct COM port. If that does not work - ASCOM driver is developed for specific version of autofocuser firmware (specified in the readme file). We recommend you to always use latest firmware and latest ASCOM driver.

Can you explain the ASCOM driver settings?

General settings

  • COM port - virtual COM port, assigned to your focuser.
  • Reverse direction - reverses motor direction.
  • Trace on - ASCOM driver trace log. If you experiance autofocuser issues, turn this setting on and send us the log files. They are located in "C:\Users\username\ASCOM" (Windows).


  • Step size - supports step sizes from 1 to 1/8. Generally, we recommend 1/2 step size, but in some cases (no 1/10 knob for example) other step sizes are more appropriate.
  • Speed mode - speed of the motor, available options: Low, Medium, High. Defaults to High. Lower speeds can cause more vibration but better accuracy. We recommend that you use 1/4 or 1/8 step size for lower speeds to reduce the vibration.
  • Settle buffer - if your focuser has any play, this can affect the autofocuser performance. SGPro for example goes aways from current position and than starts traversing back. When it changes focus direction (traverse back), focuser play can cause FOV to jiggle just a bit, which causes enlongated stars on the next exposure. Settle buffer option returns IsMoving as TRUE for specified time after focuser reaches target position, letting it to settle a bit. This only works well from SGPro version 3.0.0 beta and later.
  • Max. position - maximum position of focuser (in steps).
  • Max. movement - maximum position change in a single movement (in steps).

On next connect

  • Reset settings - if you experiance weird focuser behavior or for example hit 0 or max focuser position, you can reset the settings to the defaults with next connect.
  • Set position - change absolute position of focuser to the entered position on next connect.

Coils control

  • Coils mode
    • Always on (recommended): coils are powered at all times
    • Idle - off: coils are turned off when focuser is not moving
    • Idle - coils timeout: coils are turned off after a specified amount of time from the last move

    IMPORTANT: there are some scenarios when coils can be turned off after a period of time (e.g. manual focusing via software). But generally, we recommend you to use Coils mode "Always on" for autofocusing procedures, as turning the coils off results in lost position of the motor. Additionally, if coils are turned on at all times, motor holds the focuser position and prevents slipping.

  • Idle - coils timeout (ms) - timeout period for Coils mode "Idle - coils timeout (ms). After this period from last movement, coils turn off.
  • Current - move - current used for moving the motor. More current results in bigger torque. 75% is recommended.
  • Current - hold - current used for holding the position when motor is not moving (Coils mode "Always on"). More current results in bigger torque. 75% is recommended.


  • Reboot AF1 - soft reboot of the unit.
  • Firmware version - message box with current firmware of the connected unit.

I have changed the ASCOM settings but they have no effect, what can I do?

That happens if you change the settings while connected to the focuser. In order for ASCOM settings to have effect, you have to first disconnect from the autofocuser, change the settings and connect again.

How can I use the focuser in combination with the rest of my equipment (camera, guiding, mount...)?

Mounting of focuser is up to the customer, as stated in IMPORTANT section of autofocuser page. We recommend you mounting via timing belt, because it is less invasive to the focuser than shaft to shaft coupling. We also separately sell 3D printed mounting adapters (with L bracket and timing belt) for some focusers. You can check more in autofocuser mounting adapter section.

Can I control the focuser manually?

There is no manual controller for the focuser since it is meant for astrophotography. However, you can control it from any software that supports ASCOM standard, for example SGPro.

Stepper motor is very noisy while holding position. What can I do?

AF1 tends to release a bit annoying coils whinning noise while holding position. You can reduce the noise by setting holding current to 25%. But this reduces the holding torque, so do this at your own peril.

Timing belt is too loose/tight. What can I do?

L bracket has slotted holes. Try undoing the 4 bolts that connect the motor to the L bracket and moving it up/down.

When focuser is turning, it causes vibration. What can I do about it?

Some amount of vibration is normal with stepper motors, included in our focusers. If you are using full step or half step mode, try to change it to 1/4 or 1/8 in ASCOM driver properties and increasing number of steps per change in SGP.

SGPro autofocus graph spike on right is causing smart focus to move away from in-focus position instead of towards. How can I fix this?

This can happen if you have any play in the focuser drawtube. Please check Settle buffer in ASCOM settings section.