I received my CFF 250mm CC F15 (quartz mirror) last September and have had it out around a dozen or so nights since.
Optically it appears to be of excellent quality, and shows very tight stars once the mirror is thermally stable and seeing is good.
Mechanically it is also excellent, and I would rate it equal to any of the top scope manufacturers in quality.
The scope arrived from overseas packed well, but was out of collimation a fair amount at the secondary. It was simple enough to dial in on a star using the precise adjustments since I did not have the Takahashi collimation scope at the time.
Once I acquired the Tak TCS I perfected collimation on the secondary and a slight adjustment of the primary.
I asked Catalin to adjust the primary spacing so a binoviewer can be used easily without needing the GPC. Switching from mono mode to bino mode only requires a 50mm extension to be removed between the diagonal and focuser.
My first views of Saturn were very sharp and had the etched appearance that I'm used to seeing with my AP160. The big difference being the exit pupil size and eyepiece necessary to achieve powers above 150x.
The negatives I find using this type of scope are:
1) Fans do need to be run often in warm weather to keep up with dropping temperatures.
2) Long focal length means the seeing needs to be good or better to enjoy the high powers this scope provides. Not something that happens on a regular basis in my region.
3) The 4 vane secondary support creates a diffraction spike on bright stars and Jupiter/Venus that is tolerable, but takes getting used to after many years of refractor and SCT use.
I spend most nights using my scopes visually, but also do some AP with an AP130GT or AP Stowaway. Star tests are done when first acquiring an optic, but I don't spend a lot of time studying it as tight binary stars or planets are more interesting to prove the optics ability.
When I set the scope up next time in my observatory, I will take some photos of defocused stars on both sides of focus and post them here for those who are interested in analyzing the optics. Just let me know what you would like to see.
Edited by ZX12, 01 December 2019 - 10:48 PM.