I utilized an Ultima 2x shorty barlow with just the visual back, no diagonal.
I am attaching images of Rigel, Sirius, the trapezium (6 stars if you look closely) and Jupiter, all taken without touching the imaging stack. I really love the CPC, I had alignment right on, for almost all the objects I went after, the objects were in the imaging window! These images are single frame raw dumps out of the avi files.
I never realized how easy it was to do this. (We also did Sirius with a C-11 with an Orion Imager, and had very similar images when the gain was adjusted to keep Sirius from blooming too much. The imager blows out the SPC-900 on faint objects, but with Sirius, the best images were very similar.)