This is a holder for my 30mm diameter star finder which I needed to fit to my new telescope's slider.

It's inspired by https://www.printables.com/model/165854-astronomy-mounting-bracket-for-laser-pointer holder which was just too small for my needs.

This one is slightly bigger, inner diameter is 30mm.

I used hot-fitted screws M3 (same as Prusa uses for MK3S) 10mm long. 8mm would work as well.

I have reinforced the tube's part where screws are inserted to make thread more straight and a little longer.

Also the length of the tube is longer to allow higher precision when setting it up.

One of my screw's cap was hitting the telescope's knob, so I've included “shaved” version to keep the clearance.

• Printer: MK3S+
• Nozzle: 0.6 nozzle
• layer height: 0.24
• infill: 30%, triangle
• perimeters: 3
• filament: generic PETG

Enjoy

UPDATE: I've added STEP file, so you can easily modify it to your needs.