This thing securely holds, positions, and aligns the primary mirror of a Newtonian telescope.This cell is designed around a 114 mm spherical primary mirror, since it's cheap enough to experiment with (around $40 for primary & secondary at this place: www.meridiantelescopes.com). Plus, a much larger mirror cell won't fit on the beds of most printers.Scaling up will certainly require some design changes, since larger mirrors are much heavier. Larger mirror cells will likely require a bigger printer bed or a modular design (check out the multi-cell arrangements below). Even at it's current size it might warp.Print out the plastic parts and assemble. I listed 1 m of 8mm threaded rod in the parts list because you probably can't buy it any shorter than that, but you'll actually need under 300 mm, in three pieces. You can get by with long M8 bolts (~65mm)if you only use a 150mm diameter tube(6").I've included a sketchup file with all the parts assembled, so you can refer to that it instructions. If you get stuck with anything, ask in the comments.Note: The new thingiverse doesn't let me edit the parts list below, but Lanthan advises you use m6x35 bolts instead of 30mm.