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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Attribution

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

Description

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)