I've done some more work on the scope in the last few weeks.
I have made a lightweight focuser holder and fixed it to the upper cage. I could have used a simple rectangular piece of plywood mounted between the upper and lower ringe on the cage, but that would put the focuser an unnecessary 18mm further out and away from the secondary, resulting in a larger secondary required. So instead I used two pieces of 3mm thick aluminium angles.
I also received the focuser, a Moonlite CLR large format 2.5" Crayford with the shortest possible drawtube at just 1". This focuser is a thing of beauty!
I wanted to reuse my existing focuser, but given the larger and fatter light cone it just isn't big enough (12.5" f/5 instead of 10" f/5). The Moonlite will be awesome I'm sure, and the repeatability of the stepper motor will be very handy.
It is quite heavy though, but as I mentioned in the previous post I can probably save some weight on my finderscope which should offset this.
Finally, I've also made the secondary holder.
My previous holder was just a piece of bent aluminium but for this bigger secondary I wanted the strings to attach further down. This gives better geometry of the wire spider and greater stability. So the simple design I used before will not work here. Therefore I had constructed a slightly different holder this time, but entirely based on the same principle. The only real difference is that I have split the metal piece where the strings attach into two, because I might need to run power to a dew heater in the future. This way I can simply run it through the spider strings.
Currently I'm keeping dew off the secondary with a 120mm fan mounted on the side of the upper cage, but since I don't know it that will cut it for the larger mirror I decided to future proof the design in this regard
I've attached a couple of low resolution photos below.
Many more photos are available at my website here:
http://www.rolfolsenastrophotography...6311067_Qv7Pcw