I'm in the process of rebuilding my 20" string scope for the third time now (Version 1 build thread here) since first light in August of 2006. Version 2 was not too complicated, involving getting the primary mirror re-figured to f3.4, and shortening the poles and strings.
My current objective is much more ambitious, given realization that in my waning years of observing I'd rather spend more time looking and less time finding things – and lug around a lighter telescope.
My plan could be called an extreme makeover as I intend to replace all wood components with aluminum. My original scope weighed in at 133# with the "50 cent" mirror being 44# itself. Version 2 was basically the same weight as I only hacked off a short section of the metal poles. I'm hoping to achieve some weight loss on each of the three main components I break the scope down to for transport (ground board, mirror box and secondary cage). I carry the mirror separately as I'd likely break my back lifting the mirror box with the mirror installed. This has been quite manageable so far. Another reason of using aluminum is to have a structure with more precise right angles and parallel dimensions, important I presume for the most accurate motorized tracking.
I'm sticking with the same string design but plan on adding motors, encoders and Sidereal Technology controller system to spend less time finding things and more time looking at things. This will be a stretch of my electronic and mechanical design skills (hence my sharing on this Forum for feedback and advice), but this is a well established system with users all over the world and not coincidentally the designer/manufacturer is a fellow club member.
Build plan/schedule is:
1. New mirror box
2. Pole and string holders integrated into mirror box
3. Design and fabricate side bearings
4. Rocker box and ground board
5. Secondary cage (not a priority at this time)
This is Version 1.0. which had a focal length of 100” requiring the ladder you see. Going up and down the ladder all night got old – and as I got older less fun. Re-figuring the mirror to f3.5 in V 2.0 meant I only occasionally had to use a step stool. In this rebuild I'm hoping to shave an inch or so off the lower components and get the scope even lower to the ground.