Motorized Stars Tracker

Author: pchretien, published on 2011-09-12

Click this button to get the 3D model


This type of astrophotography mount is often called a barndoor mount, a scotch mount or a Haig mount. This mount allows you to take long exposure of the night sky by canceling out the apparent motion of the stars in the sky.

You can get more information on this type of device on Wikipedia:

The version displayed here is made using soft wood (pine) but the final assembly should be made of hard wood such as maple.

Note: The mechanism is working as expected but I am still having some vibrations transmitted to the camera. I have to eliminate these before to try taking any pictures. Improvements are on the way … stay tuned.


  • Print all parts. You may have to design a specific mount for your motor.
  • Cut one 9 1/4″” long 3/4″ x 3/4″ piece of hard wood.
  • Cut one 12″” long 3/4″ x 3/4″ piece of hard wood.
  • Bind a 1/4″ filted rod with a radius of about 11.45″ (291mm)
  • Assemble all parts as displayed on the pictures. The distance between the center of the bearings and the center of the rod must be 11.45″.

The electronic is built using an Arduino, an Alegro 5804 driver and a cheap stepper motor. I did this some time ago and, as of today, I would use different parts such as the Adafruit motor shield and the Nema 17 motor. You’ll find more informations about this on my blog at:

Following is a short video of the mount in action:

License: Creative Commons – Attribution – Share Alike

Tags: 5804, 608, Allegro, arduino, astronomy, Barndoor Mount, Bearing, Camera, featured, Fushigi, Gear, gears, multi-part, NEMA17, photography, Scotch Mount, Stars, star_tracking, stepper, telescope