A few pictures of my progress to date. The secondary assembly is now complete (apart from painting and siliconing the secondary mirror on), as are the tube saddles / straps.
- First two images show the empty tube mounted with the completed saddles / straps. Note that the white plastic coating on the straps is just protective covering for the stainless steel face side. It will be stripped off.
- The next image shows the inside tube view of the focuser platform. The tube has been reinforced at the attachment points for the focuser, with three holes drilled and tapped for the stainless inserts to be glued (One is shown fully screwed in and glued, another partially screwed in and the third not started.
- The next image shows the jig I made to bend each of the vane pairs for the secondary support.
- The next 2 images show the assembled secondary mounted in the jig that I used to line up and drill the holes in the tube for the offset vanes (the holes for the vanes are offset since each vane does not line up with the geometric centre of the tube). Note the lugs pinned to the end of each vane; they are designed to maintain absolute stiffness - there are three pins in each vane which prevents any tendency to "swivel" as in many commercial designs.
- The last two images show the whole secondary assembly mounted in the tube (the last image shows the geometric offset of the vanes). It feels extremely stiff even when the screws are just finger tight.
Can anyone recommend the best silicone to attach the secondary mirror to the carbon fibre plate? I'm thinking maybe "Roof and Gutter" (neutral cure and good adhesion to most surfaces)?