This is a helper construction for shooting night time images with a star tracker. It's an easier model than using a barn door tracker, but a bit more expensive as you need to buy additional hardware. I own a thing called NanoTracker.

You will have to edit the model to fit your location, edit it online https://www.tinkercad.com/things/iOduLsiFtEH

The basic idea is to mount the star tracker in the right angle towards north (you can use this base plane to put a compass there). the correct angle depends on your location. Google your latitude. This is the angle you have to adjust the tracker to.