This mounts a standard 14mm diameter (customizable) green laser to a camera hotshoe, telescope, barndoor mount or other device. The mount has a bump into which you can rotate the laser button to keep it turned on. However, keeping it turned on is dangerous for eyes and passing airplanes, and may run into legal problems depending on your jurisdiction, so BE VERY CAREFUL.
I also strongly recommend attaching an infrared-block filter to the end of your green laser for some added safety.
The barn door star tracker in the photo is one based on the instructions here.
The OpenSCAD file uses and bundles my tubemesh library.