61mm Triplet Refractor Telescope

thingiverse

I have a Sharpstar 61EDPH II Triplet refractor and that it was in the batch of scopes where the objective was incorrectly configured and there was chromatic aberration. Sharpstar reviewed my images and sent me a new objective lens group and that solved the CA problem. They did not ask for or send me return instructions for the old objective and I have had them on the shelf in a box for some time now. I also have a GSO focuser laying around that I believe I pulled from an Orion ST-80A doublet I used to have. I decided that I could put that objective to use visually or with filters if I did decide to image with it. I took some measurements and went out to tinkercad and designed a tube to house the objective group and attach it to a focuser. I ended up printing 3 pieces in the design. I incorporated a vixen dovetail into the focuser to lower objective group. I printed an upper objective group and a dust cap. I used black PETG filament. I haven’t spray painted the inside of the tube with flat black paint yet to lower the chance of any reflections on the plastic surface. I figure I will worry about that at some point if I choose to do so. I have been able to achieve focus with both 2” and 1.25” diagonals and am quite happy with the resulting ‘free’ triplet. UPDATE: I have redone two of the three pieces using OpenSCAD and have included the .scad files and the updated STL files for these. I will be working on the third piece and getting it out there as time permits. I also rounded the edges of the upper optics housing v2 in Fusion 360. UPDATE 2: I actually managed to get the lower housing redesigned in OpenSCAD. Note, I have not printed the updated files to make sure they were accurate but I used all of the measurements from the other STL files I generated so they should be good unless I made a typo. I did make the riser a little taller and the flanges to connect the upper and lower are in a different orientation than the original. The was to keep my brain from having to think how to rotate the flanges in OpenSCAD without changing the spacing.