Far out that's cool Stefan
love the box pattern approach for welding the forks. I was involved with building something similar (in appearance) in the mid 80's but using RHS and gussets etc
to hold a massive Hale 200" style 18" F5 OTA, also made from RHS and gussets, but equatorially mounted using pillow block bearings.....ended up in the scrap yard just a couple of years ago
Mike