Hi Astronut, No I don't think I would worry re filters, the mirror is pretty exposed anyway, I don't think it would make much difference.
18 pt mirror cell virtually complete. Note, this is a temporary cell that I will use while establishing if the mirror needs refiguring. The final cell will be a 27 pt glued one similar to Peter Bobroff's design (If Peter lets me "steal" the design that is
). The collimation adjustment is accessed from the front of the telescope. Using length of 16mm aluminium tube with a slot cut in the end the 2 top collimation bolts can be adjusted while looking through the eyepiece. The bottom collimation bolt requires a 17mm spanner to adjust.
Mirror box basic structure is there, still have to fabricate lower truss attach points. The MB internal dimensions give 50mm clearance all round the mirror with is a little bigger than the Obsession style MB. However it is lower in height at 250mm. To allow transport in the boot of a small/medium car (Holder Astra) the altitude bearings will be removable, I am anticipating about 500mm radius at this stage. Current weight of MB is 20kg incl mirror.
As a risk mitigator I am using a dummy mirror during the construction work, it is fabricated from plywood and lead and replicates the dimensions and weight of the actual mirror. I didn't bother to replicate the F4.5 curvature in the front face though
If it is clear tomorrow night I will probably replace the "dummy" mirror with the real one, attach the UTA to the MB using a length of aluminiun C channel and clamps and determine UTA/MB distance requirements.
Cheers,