In this part of the site some solutions adopted for the construction of the 40 cm will be shown in detail.
The model depicted in the photos is still in an advanced stage of development: I still needed a hard wood due to the tightness of the thread of the slats, but I was not sure which option to choose between the classic one, with two rings with central focuser (and therefore with a robust protection "cage") or the single ring one.
I opted for the second solution, believing that everything would be lighter. I was wrong. The single thin ring tends to deform under the thrust of the ribs, which are in tension, and the weight of the focuser and finder group causes the support of the first to flex slightly. It may be fine for the 40cm, but for the quality standard I am looking for, the 50cm currently under construction will have the classic 2-ring structure, with the benefit of shorter battens as well.