Star Tracker

With this, you can take long exposure pictures of the night sky without resulting star trails. Instead of spending hundreds or 1000+ for a lens, you can get similar results with this.


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The design type is widely spread, I do not know who came up with it first.


  • Source code provided, Inventor CAD files provided (student licenced)
  • excel sheet to calculate the rotation speed table included. Needed if you use other dimension, threads, motor
  • the stepper driver is powered directly with 5V from the powerbank. The power input pins are not used.
  • My experience: Polar Finder Scope is not needed, at least for wide angle shots
  • One Button control:
  • Plug in USB cable
  • 1st Button Press: rotates to initial position and starts tracking
  • Button Press: go back to initial position and continue tracking

Materials and methods

I printed in PLA, since warping of ABS could affect accuracy. Nylon would be perfect i guess, if you can print it.
The "coupling flex" is printed in soft PLA.
- 2.5mm drill bit
- M3 thread cutter
- 9mm thick board
- hinges (low play)
- Powerbank used: eStuff 2200
- Bearings: 12 x 8 x 3.5mm
- Stepper Driver: Easydriver
- Endswitch
- Thread insert: Adapter 3/8" to 1/4"
- M5 threaded bar, M5 long nut (20mm)



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830035d77d3a311a3f3c773198e6914a?default=blank&size=40Kliment Ognianov added this to the Things to make collection ago
743564ba4e1c01350ec50932fc439839?default=blank&size=40Max Nielsen commented ago

Thank you verry much.

Mini img 20210718 183648wololooo commented ago

Added two pictures of the inside of the electronics box. (Arduini Micro, Stepper Driver (easydriver), pulldown resistors

743564ba4e1c01350ec50932fc439839?default=blank&size=40Max Nielsen commented ago


Verry nice and clean design, I'm in the process of building it :-)

Do you have a picture of the inside of the electronics box.

Mini img 20210718 183648wololooo published this design ago