Summary

I have Bresser Pollux 150/1400 with EQ-2, so I made a polar finder holder.

The EQ-2 mounting point diameter 45mm
Polar finder Sky-Watcher EQ3, diameter 19mm

Assembly parts :
4x Bolts M4x20
1x Bolt M6x20
1x Nut M6 self-locking
2x Plastic sheet 20mm x 60 mm between the bolts and polar finder ( to prevent scratching )
I've used a sheet from plastic wrapping of a glue tube.

Superglue

The threads in the holes need to be tapped with M4.

Print Settings

Printer Brand:

Prusa

                                            <p class="detail-setting printer"><strong>Printer: </strong>                     <div><p>i3 MK3</p></div></p>                                                                                <p class="detail-setting rafts"><strong>Rafts: </strong>                     <div><p>Doesn't Matter</p></div></p>                                                                                <p class="detail-setting supports"><strong>Supports: </strong>                     <div><p>No</p></div></p>                                                                                <p class="detail-setting resolution"><strong>Resolution: </strong>                     <div><p>0.2</p></div></p>                                                                                <p class="detail-setting infill"><strong>Infill: </strong>                     <div><p>15%</p></div></p>                                                    <strong>Filament:</strong> Gembird PETG                Gray                    <br>                        <p class="detail-setting notes"><strong>Notes: </strong>                    </p><div><p>Use supports, only if printed at once.<br>I printed the parts and glued them together.</p></div>

Post-Printing

                <p class="detail-image"><img src="https://cdn.thingiverse.com/assets/c8/2c/01/b6/a1/1ff3fe27-53da-412d-9710-09f2a0952089.jpg"></p>

Polar Finder holder - Bresser EQ-2