AF3s Askar 200mm dovetail kit - assembly instructions

Step 1

Parts required:
  • 1x AF3s (preassembled to the mounting plate)
  • 1x Askar 200mm dovetail
  • 2x 16mm M6 bolts

Align the AF3s motor with the dovetail in the similar manner as in the photo.

Tighten M6 bolt so they are approximate in the center of the dovetail slotted hole.

Step 2

Parts required:
  • 1x AF3s with dovetail
  • 1x Askar 200mm
  • 1x ALU raise block
  • 1x 60mm M5 bolt

Attach the raise block onto the dovetail.

Insert 60mm M5 bolt into the dovetail.

Tighten the bolt.

Step 3

Parts required:
  • 1x Askar 200mm with AF3s motor
  • 1x 3D printed MXL ring
  • 2x 10mm M3 bolts

Put the 3D printed MXL ring onto the lens coarse focusing ring, so its in line with the MXL pulley on the AF3s. Insert and tighten 2x 10mm M3 bolts.

Step 4

Parts required:
  • 1x Askar 200mm with AF3s motor and MXL ring
  • 1x MXL timing belt

Slide the belt from the front of the lens and put it onto the MXL pulley.

Now put the rest of the belt onto the 3D printed ring. Work by going through the length of the belt gradually. Some force should be required.

  • if you can put the belt on too easily, there is not enough tenison. Undo the M3 bolts holding the motor in the L bracket and move the motor LOWER. If you are having trouble accessing the M3 bolts, you can take the focuser off the dovetail by undoing the 2x M6 16mm bolts.
  • if you cant get the belt onto the ring, there is too much tension. Undo the M3 bolts holding the motor in the L bracket and move the motor HIGHER. If you are having trouble accessing the M3 bolts, you can take the focuser off the dovetail by undoing the 2x M6 16mm bolts.

Step 5


Test the motor with manual hand controller/AF3 control panel or 3rd party program via ASCOM.

  • if the pulley does not grab onto the teeth and rotates freely, the belt is too loose. Return to the step above.
  • if the motor is stalling and can't move the helical ring, the belt is too tight or the motor move current is too low. To change belt tightness, return to the step above. To increase the motor move current, see FAQ for details.

Try racking the telescope all the way in/out to test all positions. If you can, also turn the telescope facing upwards and try racking it out, as this is the position which requires the most force.

Thats it! Happy autofocusing!