I rarely use my c11 HD at f10 . I usually use a focal reducer and run at about f5. I am new to the CEM60 . I just moved over from a CGEM DX. I was not one of the lucky ones that received a trouble free CGEM and I finally threw in the towel . I am not looking to do a lot of long exposure imaging although I may give it a shot someday. I mostly just do video astronomy with my Mallincam for now. I also have an iEQ45 Pro that I use with a C8 HD SCT and a Lunt 60 mm DS. Both of these mounts have not seen first light due to the weather. I think I may have caused a disturbance in the force with 2 new mounts. Sorry about the weather guys. In a couple of weeks I will be going to a star party called ECVAR (East Coast Video Astronomy Rendezvous) in Galax, Virginia for a week with my friends from nightskiesnetwork.com . We will be broadcasting from there. I hope to get any bugs worked out on these mounts at that time.