|
Update: I have completed all the carbon fibre tube bonding for the back of the scope the front section is to wait until I do a star test (I want it and the focuser to be able to slide on the assembled tube rails). Once I am happy with the camera focus I will mark the front on the tubes and bond it in place. The photo shows the tube is still in its raw state - ie the epoxy cleanup has not been done yet. I want to complete all the epoxy work before I get into the messy and tedious cleanup phase. Trust me it will look much better when that is finished (anyone familiar with my refractor build would have seem the end result).
I have considered a couple of solutions for the secondary mount, a curved vane design and the normal four vane. I looked at DIY builds of both and I thought the curved vane probably does not provide the support that the four vane does and it (the curved vane) would have to be thicker. Typically people use stainless steel rulers bent to the shape of the curve, in the four vane there are plenty of hacksaw blade vane solutions around. I will be building the four vane using hacksaw blades (deburred of course). The secondary vanes will be attached to the front ring with four timber posts, a bit hard to visualise without a drawing I know.
I have completed the fabrication of the mirror cell and tested it on the tube today, (alignment photo attached). It uses a Push - Pull bolt set with springs on the Pull bolts, pretty much exactly the way the Stellafane one is made. All the hardware for the cell is from Bunnings. I have two springs sets, a light one and a heavy one, the photo shows the light ones (the heavy ones are the same springs I used on my old 12" dob). The side support L brackets are not installed yet, I need to do the final finish of the cell before I attach the side supports.
Next step will be to put on the tube extensions at the front (for the focuser and secondary section to slide on), and the complete cleanup of the epoxy on the tube assembly.
I bought a GSO 2" Linear Focuser to use, as they are strong, and relatively cheap, I also have received the fan for the rear plate.
More soon. I am aiming to have this done, or at least useable, by the next new moon so I can take it out to Bretti for field trials. I may not have the shroud ready by then but Bretti is dark enough that I may not need it.
|