Thanks Andy and Robin for your kind words. I enjoy tinkering as much as using which is just as well given the near perma-cloud here. One advantage of the fiber feed is I can play with new bits without disturbing the telescope and it’s pointing.
Sorry Tony, I don’t have any plans as such I basically read all I could find and then pinched the ideas. I then drew a layout on paper and transferred it to ceramic base, drilled holes, and fiddled about until it worked. The optical layout it is similar to the Shelyak Instruments eShel but on its side. I went for high thermal mass so it is in a large plywood box covered in 2″ back insulation. It has an air to air peltier cooler controlled by a Laird Tehnologies PID controller. Once stabilised it is better than +/- 0.02 degrees so the calibration remains stable during a nights observing.
Happy to answer any specific question or help anyone trying to do similar things.