Barn Door Star Tracker
To take clear long exposure images of the night sky with exposure times past 30 seconds or so, some sort of tracking must be employed, since the Earth’s rotation will cause stars to blur/rotate across the frame.
Extremely expensive camera mounts exist that do this very well, but there’s a cheaper and simpler way to accomplish something similar. It’s called a “barn door” star tracker. Essentially, it’s a hinge that slowly opens, exactly countering the rotation of the earth.
I searched through quite a few online tutorials of pre-existing barn door trackers, but since I had access to a 3D printer at school and some basic shop tools, I thought it would be fun to create my own.
Using a few custom 3D-printed parts, some wood, a hinge, a cheap stepper motor, and an Arduino, I was able to build a functioning star tracker:
