Hey Jeff,
Thanks for the back focus attachment. That really helped me out.
I went through some of my images (both with and without the reducer) and what I found was; without the reducer my stars are round at the edges while with the reducer it looks like my back focus is too far out.
The part that gets me is I'm running the celestron reducer F6.3 with the celestron T-Adaptor designed for the celestron SCT C8. What is more interesting is that my issue has been around for many moons and Celestron hasnt done anything about it ie. bring out a shorter T-Adaptor.
https://www.cloudynights.com/topic/5...cer-corrector/