As many readers know, I’ve long appreciated and been interested in the secondary spider as an opto-mechanical structure. It probably goes back to my days at the AAT when it was my routine responsibility to swap out the Top End (UTA) of the 3.9m telescope, an operation performed with a 7T crane fitted integral within the dome. In control from the crane platform at the inside top of the dome high above the telescope I would lift and exchange the entire UTA from a choice of 4, providing the AAT with a wide range of focal length options and Prime Focus instruments. It was from there that I first noticed that the spider vanes were offset from the center, and curiosity piquied I had to ask why.
Thirty years later its just a hobby, but...I still enjoy playing with the engineering principles that make for an excellent secondary support system. And with some difficult decisions to make for my planned 2 x 16” bino, I decided to move from theory and run a series of performance test on a wide range of spiders, from wire to curved thru to some of the exotic shapes we arrived at in this thread here.
I want to see what gives, what moves, what flexes, and what holds. And take no prisoners.
Hence this monster in my garage...
Edited by Oberon, 23 January 2019 - 03:57 AM.