AF3s SpaceCat Dovetail kit - assembly instructions

210 dovetail

Step 1

Parts required:
  • 1x 3D printed mounting plate
  • 1x NEMA 14 L bracket
  • 4x 6mm M3 bolt

Put the L bracket onto the mounting plate as demonstrated on the photo below.

Secure the L bracket onto the mounting plate with 4x M3 bolts. Align the L bracket with the mounting plate before tightening the bolts.

Step 2

Parts required:
  • 1x 3D printed 16T MXL pulley
  • 1x AF3s unit

Put the pulley onto the shaft, so that one of the setting bolt is in line with the straight surface on the motor shaft.

Slide the pulley onto the shaft, so the end of the shaft is flush with the top surface of the pulley. Tighten the set bolts carefully.

Step 3

Parts required:
  • 1x 3D printed mounting plate with L bracket
  • 1x AF3s with pulley
  • 4x 6mm M3 bolts

Put the motor on the straight surface so the shaft is facing upwards. Slide the L bracket over the pulley so it rests on the motor enclosure like show on the photo.

Secure the L bracket with 4x M3 bolts. Before tightening the bolts, make sure the motor is in the middle position inside L bracket M3 slots.

Flip the motor over and locate the M3 tensioning set bolt.

Now flip the motor on the side and bolt it until it barely touches the motor enclosure.

Step 4

Parts required:
  • 1x Motor assembly
  • 1x 110 dovetail
  • 2x 16mm M6 bolts

Put the motor onto the straight surface, so the mounting plate is facing upwards, locate M6 holes marked on the photo.

Put the dovetail onto the mounting plate, so the bottom of the dovetail is pointing upwards. Align the mounting plate holes to the dovetail slotted holes.

Secure the motor with 2x M6 bolts, but do not tighten them yet.

Step 5

Parts required:
  • 1x RedCat/SpaceCat/WhiteCat
  • 1x 3D printed helical focuser MXL ring
  • 2x 10mm M3 bolt

Put the female part of 3D printed ring onto the helical focuser facing the front of the telescope. The side of the ring facing the back of the telescope must be in line with the beginning of the helical focuser rubber ring.

Put the male part of 3D printed ring onto the female part and insert 2x M3 bolts.

Tighten the bolts alternately just so the bolt grabs onto the thread in the female part of the ring. After both bolts are connected, tighten them down so the teeth on the joint are aligned.

Step 6

Parts required:
  • 1x Motor & dovetail assembly
  • 1x RedCat/SpaceCat/WhiteCat
  • 1x extension block (3D printed or ALU)
  • 2x 50mm M6 bolts

Put the extension block between the motor & dovetail assembly and the telescope, attach the dovetail with 2x M6 bolts. Do not tighten the bolts yet.

Slide motor & dovetail assembly so that the 3D printed pulley is in line with the 3D printed ring. Tighten down all 4 M6 bolts.

Step 7

Parts required:
  • 1x RedCat/SpaceCat/WhiteCat & Motor & dovetail assembly
  • 1x MXL timing belt

Put the dew shield off and into shooting position. Slide the timing belt onto the telescope from the front.

Once the belt is through, put it over and onto the 3D printed pulley. Leave the upper part of the belt in front of the 3D printed ring.

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 8


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.

Step 9 (optional)

Parts required:
  • 1x RedCat/SpaceCat/WhiteCat
  • 1x v1 ring guide scope shoe
  • 2x 8mm M4 low head profile bolts

Put the guide scope shoe onto the v1 ring and align it with the holes.

Tighten the bolts.

Attach the guide scope

Happy guiding! :)

Thats it! You can now test the autofocusing procedure. Check out our FAQ for details.

110 dovetail

Step 1

Parts required:
  • 1x 3D printed mounting plate
  • 1x NEMA 14 L bracket
  • 4x 6mm M3 bolt

Put the L bracket onto the mounting plate as demonstrated on the photo below.

Secure the L bracket onto the mounting plate with 4x M3 bolts. Align the L bracket with the mounting plate before tightening the bolts.

Step 2

Parts required:
  • 1x 3D printed 16T MXL pulley
  • 1x AF3s unit

Put the pulley onto the shaft, so that one of the setting bolt is in line with the straight surface on the motor shaft.

Slide the pulley onto the shaft, so the end of the shaft is flush with the top surface of the pulley. Tighten the set bolts carefully.

Step 3

Parts required:
  • 1x 3D printed mounting plate with L bracket
  • 1x AF3s with pulley
  • 4x 6mm M3 bolts

Put the motor on the straight surface so the shaft is facing upwards. Slide the L bracket over the pulley so it rests on the motor enclosure like show on the photo.

Secure the L bracket with 4x M3 bolts. Before tightening the bolts, make sure the motor is in the middle position inside L bracket M3 slots.

Flip the motor over and locate the M3 tensioning set bolt.

Now flip the motor on the side and bolt it until it barely touches the motor enclosure.

Step 4

Parts required:
  • 1x Motor assembly
  • 1x 110 dovetail
  • 2x 16mm M6 bolts

Put the motor onto the straight surface, so the mounting plate is facing upwards, locate M6 holes marked on the photo.

Put the dovetail onto the mounting plate, so the bottom of the dovetail is pointing upwards. Align the mounting plate holes to the dovetail slotted holes.

Secure the motor with 2x M6 bolts, but do not tighten them yet.

Step 5

Parts required:
  • 1x RedCat/SpaceCat/WhiteCat
  • 1x 3D printed helical focuser MXL ring
  • 2x 10mm M3 bolt

Put the female part of 3D printed ring onto the helical focuser facing the front of the telescope. The side of the ring facing the back of the telescope must be in line with the beginning of the helical focuser rubber ring.

Put the male part of 3D printed ring onto the female part and insert 2x M3 bolts.

Tighten the bolts alternately just so the bolt grabs onto the thread in the female part of the ring. After both bolts are connected, tighten them down so the teeth on the joint are aligned.

Step 6

Parts required:
  • 1x Motor & dovetail assembly
  • 1x RedCat/SpaceCat/WhiteCat
  • 1x extension block (3D printed or ALU)
  • 2x 50mm M6 bolts

Put the extension block between the motor & dovetail assembly and the telescope, attach the dovetail with 2x M6 bolts. Do not tighten the bolts yet.

Slide motor & dovetail assembly so that the 3D printed pulley is in line with the 3D printed ring. Tighten down all 4 M6 bolts.

Step 7

Parts required:
  • 1x RedCat/SpaceCat/WhiteCat & Motor & dovetail assembly
  • 1x MXL timing belt

Put the dew shield off and into shooting position. Slide the timing belt onto the telescope from the front.

Once the belt is through, put it over and onto the 3D printed pulley. Leave the upper part of the belt in front of the 3D printed ring.

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 8


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.

Step 9 (optional)

Parts required:
  • 1x RedCat/SpaceCat/WhiteCat
  • 1x v1 ring guide scope shoe
  • 2x 8mm M4 low head profile bolts

Put the guide scope shoe onto the v1 ring and align it with the holes.

Tighten the bolts.

Attach the guide scope

Happy guiding! :)

Thats it! You can now test the autofocusing procedure. Check out our FAQ for details.