Ok, its been a few weeks since my last update. I have been slowly getting through the commissioning. Some observations below.
- The secondary position was way out. I have had to move it a considerable distance toward the primary. I think so far I have moved it about 20mm and I am still not convinced that I have it in the correct position. The size of the secondary is enormous at 110mm across the minor axis and that can be quite deceiving in an observatory with dark walls. I am now using a white piece of cardboard to help with positioning.
- There was astigmatism present from the secondary glue. I have reglued that into position and this has alleviated the astigmatism.
- The primary without side support moves, just a tiny amount, which affects collimation. When the primary arrived it was taped and glued to the mirror cell. This was causing astigmatism and pinched optics. I have now once again taped and glued the primary with small dobs of glue and tape to prevent the primary from moving during slews. Their idea is sound, just the execution was a bit off. I suspect that the glue was applied during hot periods in England and this caused the silicone to off gas and cure very quickly and pinch the optics.
- The collimation is still in need of fine tuning. I plan on doing that tonight with a visit to the site if the weather holds. A fast scope like this needs star test collimation to get it 100% correct.
- The secondary assembly hold star shapes quite well. I don't see the changes in star shapes I was seeing in the GSO. That would no doubt be a combination of the secondary assembly and the focuser assembly.
- I'll be giving a full review of this scope once I have it working and imaging.
See images below for first light. As you can see there is still an element of miscollimation present and a bit of a way to go yet. Perhaps even some tilt present, but I won't know that until I have the collimation nailed down. Detail appears to be sound overall.